Animal models in urological disease and sexual dysfunction

Progress and challenges in intravesical drug delivery

INTRODUCTION

Intravesical drug delivery (IDD) has gained recognition as a viable approach for treating bladder-related diseases over the years. However, it comes with its set of challenges, including voiding difficulties and limitations in mucosal and epithelial penetration. These challenges lead to drug dilution and clearance, resulting in poor efficacy. Various strategies for drug delivery have been devised to overcome these issues, all aimed at optimizing drug delivery. Nevertheless, there has been minimal translation to clinical settings.

AREAS COVERED

This review provides a detailed description of IDD, including its history, advantages, and challenges. It also explores the physical barriers encountered in IDD, such as voiding, mucosal penetration, and epithelial penetration, and discusses current strategies for overcoming these challenges. Additionally, it offers a comprehensive roadmap for advancing IDD into clinical trials.

EXPERT OPINION

Physical bladder barriers and limitations of conventional treatments result in unsatisfactory efficacy against bladder diseases. Nevertheless, substantial recent efforts in this field have led to significant progress in overcoming these challenges and have raised important attributes for an optimal IDD system. However, there is still a lack of well-defined steps in the workflow to optimize the IDD system for clinical settings, and further research is required to establish more comprehensive in vitro and in vivo models to expedite clinical translation.

Mechanism of traditional Chinese medicine in treating overactive bladder

Overactive bladder syndrome (OAB) has made increasing progress in mechanism and treatment research. Traditional Chinese medicine (TCM) is a common complementary therapy for OAB, and it has been found to be effective. However, the intervention mechanism of TCM in the treatment of OAB is still unclear. The aim of this review is to consolidate the current knowledge about the mechanism of TCM: acupuncture, moxibustion, herbs in treating OAB, and the animal models of OAB commonly used in TCM. Finally, we put forward the dilemma of TCM treatment of OAB and discussed the insufficiency and future direction of TCM treatment of OAB.

Lower Urinary Tract Diseases in Guinea Pigs: A 14-Year Retrospective Study (2004-2018)

The clinical records of all guinea pigs diagnosed with a lower urinary tract disease in a single veterinary hospital, over a period of 14 years (2004−2018), were retrospectively searched in order to characterize this population and investigate the potential association between the epidemiological and clinical variables. A total of 117 clinical cases were identified, corresponding to 57 animals. Urolithiasis was the most common diagnosis (n = 52; 44.4%), followed by cystitis and/or a urinary tract infection (UTI). Several statistically significant associations (p < 0.05) were found between different variables, showing that female guinea pigs were more likely than the male ones to have a previous family history of urinary disease, to present dysuria and stranguria at admission, and to suffer recurrence. Moreover, males were more prone to urolithiasis and females to cystitis/UTI, and animals diagnosed with cystitis/UTI frequently had more clinical urinary signs and abdominal pain on palpation compared to those diagnosed with urolithiasis. Finally, the use of potassium citrate and the urethrotomy approach were associated with a better therapeutic response. Further studies are needed in larger populations of guinea pigs to confirm the present findings, especially as some of them were described for the first time.

Prolonged inhibition of bladder function is evoked by low-amplitude electrical stimulation of the saphenous nerve in urethane-anesthetized rats

To better understand the effects of saphenous nerve (SN) stimulation on bladder function, we investigated the duration of electrical stimulation as a key variable in eliciting urodynamic changes. SN stimulation is a novel approach to electrically modulating bladder function. In previous animal studies, bladder-inhibitory responses were evoked by low-amplitude (25 μA) stimulus pulses applied in short-duration (10 min) trials and at frequencies between 10 and 20 Hz. Experiments were performed in urethane-anesthetized rats that were separated into three groups: intravesical saline infusion + SN stimulation (group A), intravesical 0.1% acetic acid infusion + SN stimulation (group B), and intravesical saline infusion + no SN stimulation (group C). Changes in bladder function- basal bladder pressure (P base ), contraction amplitude (ΔP), and inter-contraction interval (T ICI )-were measured in response to stimulation trials applied for different durations (10, 20, and 40 min). Trials were also repeated at frequencies of 10 and 20 Hz. In group A, longer-duration (40 min) stimulation trials applied at 10 Hz evoked overflow incontinence (OI) episodes that were characterized by significant changes in P base (122.7 ± 9.1%, p = 0.026), ΔP (-60.8 ± 12.8%, p = 0.044), and T ICI (-43.2 ± 13.0%, p = 0.031). Stimulation-evoked OI was observed in 5 of 8 animals and lasted for 56.5 ± 10.7 min. In contrast, no significant changes in bladder function were observed in either group B or group C. Our findings show that longer-duration trials consisting of electrical pulses applied at 10 Hz are important stimulation parameters that elicit inhibitory bladder responses in anesthetized rodents.

A Rat Experimental Model for Investigation of the Effect of Diabetes on Submandibular Salivary Glands Treated with Epidermal Growth Factor

Background: Despite the plethora of research around the negative effects of diabetes on different body organs, this topic still attracts a lot of attention in order to find potential remedies that could counteract or reverse the damaging effect of diabetes. Aim: In this study, we developed a reliable experimental rat model that can be used for investigation of the ability of epidermal growth factor (EFG) in restoring the normal architecture of oral tissues after being damaged by diabetes. Methods: Eighty adult male albino rats (average weight ±220 gm) were used in the current study. Twenty rats served as control and received no treatment. Diabetes was induced in forty rats using a single injection of 65mg/kg of Streptozotocin (STZ). Out of the forty diabetic rats, twenty rats received a single daily intraperitoneal injection of EGF (10 µg/Kg) for 8 weeks. Furthermore, twenty healthy rats received the same dose of EGF and served as positive controls. The submandibular salivary glands of all rats were examined for Immunohistochemical detection of myosin in the glandular structure. Results: The EGF treated group showed comparable myosin expression to the control group. The diabetic group revealed deterioration of all components of the submandibular salivary glands. Finally, the diabetic + EGF group has demonstrated restoration of the myosin expression levels in the submandibular salivary glands to a level that is not significantly different from healthy (non-diabetic) rats in the control group (p>0.05) and significantly higher than the diabetic group (p<0.0001). Conclusion: The findings of the present study confirm previous studies and validates the use of our animal model as predictable experimental tool to investigate the effects of diabetes and EGF on different oral tissues. It also highlights the importance of further research investigating EGF as a promising treatment modality for restoration of the condition and functions of tissues damaged by diabetes not only in the oral cavity but also around the whole body.  

Review of Animal Models to Study Urinary Bladder Function

Simple Summary

The treatment of urinary bladder dysfunction requires the knowledge of bladder function, which involves physiology, pathology, and even psychology. Several animal models are available to study a variety of bladder disorders. These models include animals from rodents, such as mice and rats, to nonhuman primates, such as rabbits, felines, canines, pigs, and mini pigs. This review adapted animal models to study bladder function according to facility, priority, and disease.

Abstract

The urinary bladder (UB) serves as a storage and elimination organ for urine. UB dysfunction can cause multiple symptoms of failure to store urine or empty the bladder, e.g., incontinence, frequent urination, and urinary retention. Treatment of these symptoms requires knowledge on bladder function, which involves physiology, pathology, and even psychology. There is no ideal animal model for the study of UB function to understand and treat associated disorders, as the complexity in humans differs from that of other species. However, several animal models are available to study a variety of other bladder disorders. Such models include animals from rodents to nonhuman primates, such as mice, rats, rabbits, felines, canines, pigs, and mini pigs. For incontinence, vaginal distention might mimic birth trauma and can be measured based on leak point pressure. Using peripheral and central models, inflammation, bladder outlet obstruction, and genetic models facilitated the study of overactive bladder. However, the larger the animal model, the more difficult the study is, due to the associated animal ethics issues, laboratory facility, and budget. This review aims at facilitating adapted animal models to study bladder function according to facility, priority, and disease.

D-(+)-Galactose-induced aging: A novel experimental model of erectile dysfunction

Erectile dysfunction (ED) is defined as the inability to achieve and/or maintain penile erection sufficient for satisfactory sexual relations, and aging is one of the main risk factors involved. The D-(+)-Galactose aging model is a consolidated methodology for studies of cardiovascular aging; however, its potential for use with ED remain unexplored. The present study proposed to characterize a new experimental model for ED, using the D-(+)-Galactose aging model. For the experiments, the animals were randomly divided into three groups receiving: vehicle (CTL), D-galactose 150 mg/kg (DGAL), and D-(+)-galactose 150 mg/Kg + sildenafil 1.5 mg/Kg (DGAL+SD1.5) being administered daily for a period of eight weeks. All of the experimental protocols were previously approved by the Ethics Committee on the Use of Animals at the Federal University of Paraíba n° 9706070319. During the treatment, we analyzed physical, molecular, and physiological aspects related to the aging process and implicated in the development of ED. Our findings demonstrate for the first time that D-(+)-Galactose-induced aging represents a suitable experimental model for ED assessment. This was evidenced by an observed hyper-contractility in corpora cavernosa, significant endothelial dysfunction, increased ROS levels, an increase in cavernous tissue senescence, and the loss of essential penile erectile components.

Age-related differences in responses to hydrogen sulfide in the bladder of spontaneously hypertensive rats

OBJECTIVES

To investigate whether a response to hydrogen sulfide donors (GYY4137 and sodium hydrosulfide) and the endogenous hydrogen sulfide system (hydrogen sulfide level and expression of cysteine aminotransferase, cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase) in the spontaneously hypertensive rat bladder differ with age, we compared the responses of hydrogen sulfide donors to micturition and bladder relaxation, and the endogenous hydrogen sulfide system in the bladder of 18-week versus 12-week-old spontaneously hypertensive rats.

METHODS

GYY4137 was intravesically administered and cystometry was performed in anesthetized rats. The responses of sodium hydrosulfide were evaluated in carbachol-mediated precontracted bladder strips. Bladder hydrogen sulfide levels and expression levels of each enzyme were investigated using the methylene blue method and Western blotting, respectively.

RESULTS

GYY4137 treatment significantly prolonged intercontraction intervals only in 12-week-old rats. Sodium hydrosulfide-induced bladder relaxation was significantly attenuated in the strips of 18-week-old rats compared with that in 12-week-old rats. In the bladder dome, significant increases in hydrogen sulfide levels and in the expression of cystathionine β-synthase, 3-mercaptopyruvate sulfurtransferase, and cysteine aminotransferase were observed in 18-week-old rats compared with 12-week-old rats. However, cystathionine γ-lyase bands were not detected in bladder tissues of either group.

CONCLUSIONS

Bladder relaxation induced by hydrogen sulfide may be attenuated in spontaneously hypertensive rats in an age-dependent manner.

Cystometric Measurements in Rats with an Experimentally Induced Traumatic Brain Injury and Voiding Dysfunction: A Time-Course Study

Traumatic brain injuries (TBIs) are a serious public health issue worldwide with increased mortality as well as severe disabilities and injuries caused by falls and road accidents. Unfortunately, there is no approved therapy for TBIs, and bladder dysfunction is a striking symptom. Accordingly, we attempted to analyze bladder dysfunction and voiding efficiency in rats with a TBI at different time-course intervals. Time-dependent analyses were scheduled from the next day until four weeks after a TBI. Experimental animals were grouped and analyzed under the above conditions. Cystometric measurements were used for this analysis and were further elaborated as external urethral sphincter electromyographic (EUS-EMG) activity and cystometrogram (CMG) measurements. Moreover, magnetic resonance imaging (MRI) studies were conducted to investigate secondary injury progression in TBI rats, and results were compared to normal control (NC) rats. Results of EUS-EMG revealed that the burst period, active period, and silent period in TBI rats were drastically reduced compared to NC rats, but they increased later and reached a stagnant phase. Likewise, in CMG measurements, bladder function, the voided volume, and voiding efficiency decreased immediately after the TBI, and other parameters like the volume threshold, inter-contraction interval, and residual volume drastically increased. Later, those levels changed, and all observed results were compared to NC rats. MRI results revealed the prevalence of cerebral edema and the progression of secondary injury. All of the above-stated results of the experiments were extensively substantiated. Thus, these innovative findings of our study model will surely pave the way for new therapeutic interventions for TBI treatment and prominently highlight their applications in the field of neuroscience in the future.

Towards clinical application of tissue engineering for erectile penile regeneration

Penile wounds after traumatic and surgical amputation require reconstruction in the form of autologous tissue transfers. However, currently used techniques are associated with high infection rates, implant erosion and donor site morbidity. The use of tissue-engineered neocorpora provides an alternative treatment option. Contemporary tissue-engineering strategies enable the seeding of a biomaterial scaffold and subsequent implantation to construct a neocorpus. Tissue engineering of penile tissue should focus on two main strategies: first, correcting the volume deficit for structural integrity in order to enable urinary voiding in the standing position and second, achieving erectile function for sexual activity. The functional outcomes of the neocorpus can be addressed by optimizing the use of stem cells and scaffolds, or alternatively, the use of gene therapy. Current research in penile tissue engineering is largely restricted to rodent and rabbit models, but the use of larger animal models should be considered as a better representation of the anatomical and physiological function in humans. The development of a cell-seeded scaffold to achieve and maintain erection continues to be a considerable challenge in humans. However, advances in penile tissue engineering show great promise and, in combination with gene therapy and surgical techniques, have the potential to substantially improve patient outcomes.

Oxytocin Neurons Enable Melanocortin Regulation of Male Sexual Function in Mice

The melanocortin pathway has been implicated in both metabolism and sexual function. When the melanocortin 4 receptor (MC4R) is knocked out globally, male mice display obesity, low sexual desire, and copulatory difficulties; however, it is unclear whether these phenotypes are interdependent. To elucidate the neuronal circuitry involved in sexual dysfunction in MC4R knockouts, we re-expressed the MC4R in these mice exclusively on Sim1 neurons (tbMC4RSim1 mice) or on a subset of Sim1 neurons, namely oxytocin neurons (tbMC4Roxt mice). The groups were matched at young ages to control for the effects of obesity. Interestingly, young MC4R null mice had no deficits in sexual motivation or erectile function. However, MC4R null mice were found to have an increased latency to reach ejaculation compared to control mice, which was restored in both tbMC4RSim1 and tbMC4Roxt mice. These results indicate that melanocortin signaling via the MC4R on oxytocin neurons is important for normal ejaculation independent of the male's metabolic health.

A review of novel trends in management of canine spinal cord injury

Severe spinal cord injury (SCI) causing significant morbidity and mortality remains one of the most challenging problems in both human and veterinary medicine. Due to the restricted regeneration potential of the central nervous system (CNS) in mammals, the neurological deficit caused by spinal cord (SC) injury is permanent, and no therapeutic measures are able to completely restore neurological functions either in primates or in non-primate animals with traumatic tetraparesis/tetraplegia or paraparesis/paraplegia. The constant progress in the understanding of pathophysiologic events developing after spinal cord trauma constitute an unremitting inspiration for neuroscientists and health care professionals to test novel medicaments and treatment strategies to cope with this situation. Recent experimental studies and preclinical trials have delivered promising results. The aim of this review is a presentation of generally accepted methods of management of dogs with SCI as well as a report on new therapeutic modalities, and comment on their potential for clinical translation. The research strategy involved a search of PubMed, Medline, and ISI Web of Science from January 2010 to December 2018 using the terms “spinal cord injuryˮ and “management of spinal traumaˮ in the English language literature. References from selected papers were also scanned and evaluated for relevance.

Electrophysiology of Syncytial Smooth Muscle

As in other excitable tissues, two classes of electrical signals are of fundamental importance to the functioning of smooth muscles: junction potentials, which arise from neurotransmission and represent the initiation of excitation (or in some instances inhibition) of the tissue, and spikes or action potentials, which represent the accomplishment of excitation and lead on to contractile activity. Unlike the case in skeletal muscle and in neurons, junction potentials and spikes in smooth muscle have been poorly understood in relation to the electrical properties of the tissue and in terms of their spatiotemporal spread within it. This owes principally to the experimental difficulties involved in making precise electrical recordings from smooth muscles and also to two inherent features of this class of muscle, ie, the syncytial organization of its cells and the distributed innervation they receive, which renders their biophysical analysis problematic. In this review, we outline the development of hypotheses and knowledge on junction potentials and spikes in syncytial smooth muscle, showing how our concepts have frequently undergone radical changes and how recent developments hold promise in unraveling some of the many puzzles that remain. We focus especially on computational models and signal analysis approaches. We take as illustrative examples the smooth muscles of two organs with distinct functional characteristics, the vas deferens and urinary bladder, while also touching on features of electrical functioning in the smooth muscles of other organs.

Cauda equina syndrome in dogs - a review

A lesion of sacrococcygeal spinal nerve roots forming a structure that resembles a horse's tail results in the development of clinical entity identified as the cauda equina syndrome (CES). The disease can evolve slowly and symptomatology can be incomplete, but the fully developed CES is characterized by pain and altered sensation in the pelvic extremities, tail, perianogenital region, paresis or plegia of hind limbs, incontinence and impotence. Major causes of CES in dogs are degenerative changes of the lumbosacral vertebral column, haematoma, inflammation, neoplasm or trauma. The diagnosis is based on history, clinical presentation, neurological symptomatology, spinal röntgenography, computed tomography, and magnetic resonance imaging. In animals experiencing initial episodes of CES, conservative therapy can be attempted. But the only rational treatment of patients with severe neurological deficit is surgical decompression of the neural structures. The outcome depends on the underlying aetiology and the degree of sensory, motor and autonomic dysfunction. Canine and porcine experimental models mimicking the CES showed the involvement of intrinsic spinal cord structures. This points out the need for an early diagnosis followed by aggressive management before irreversible neuronal lesions develop. The search strategy involved the PubMed, Medline, Embase and ISI Web of Science from January 2000 to August 2017 using the terms 'cauda equina syndrome' and 'lumbosacral stenosis' in the English language literature; also references from selected papers were scanned and relevant articles included.

Improved voiding function by deep brain stimulation in traumatic brain-injured animals with bladder dysfunctions

OBJECTIVE

Traumatic brain injury (TBI) is a global scenario with high mortality and disability, which does not have an effectual and approved therapy till now. Bladder dysfunction is a major symptom after TBI, and this study deals with the alleviation of bladder function in TBI rats, with the aid of deep brain stimulations (DBS).

METHODS

TBI was induced by weight drop model (WDM) and standardized with the experimental subjects with variable heights for weight dropping. The rats survived after TBI were considered for bladder dysfunction observations. DBS with variable stimulation parameters like cystometric analysis and MRI studies were also performed.

RESULTS

After experimental studies, TBI 2-m-height crash was determined as suitable parameter due to minimal mortality rate and significant reduction in the voiding efficiency from 67 to 28%, whereas DBS significantly reversed the value of voiding efficiency to 65-84%. MRI studies revealed the severity of TBI impact and DBS localization.

CONCLUSION

The results showed profound therapeutic effect of PnO-DBS on voiding functions and bladder control on TBI rats.

Spinal Cord Injuries in Dogs Part II: Standards of Care, Prognosis and New Perspectives

Severe spinal cord injuries (SCI), causing physical handicaps and accompanied by many serious complications, remains one of the most challenging problems in both, human and veterinary health care practices. The central nervous system in mammals does not regenerate, so the neurological deficits in a dog following SCI persists for the rest of its life and the affected animals display an image of permanent suffering. Diagnostics are based on: neurological examination, plain x-rays of vertebral column, x-rays of the vertebral column following intrathecal administration of a water-soluble contrast medium (myelography), x-rays of the vertebral column following epidural administration of a contrast medium (epidurography), computed tomography (CT) and/or magnetic resonance imaging (MRI). Currently, only limited therapeutic measures are available for the dogs with SCIs. They include: the administration of methylprednisolone sodium succinate (MPSS) during the acute stage; early spinal cord decompression; stabilisation of vertebral fractures or luxations; prevention and treatment of complications, and expert rehabilitation. Together with the progress in the understanding of pathophysiologic events occurring after SCI, different therapeutic strategies have been instituted, including the local delivery of MPSS, the utilisation of novel pharmacological agents, hypothermia, and stem/precursor cell transplantation have all been tested in the experimental models and preclinical trials with promising results. The aim of this review is the presentation of the generally accepted methods of diagnostics and management of dogs with SCIs, as well as to discuss new therapeutic modalities. The research strategy involved a PubMed, Medline (Ovid), Embase (Ovid) and ISI Web of Science literature search from January 2001 to December 2017 using the term “spinal cord injury”, in the English language literature; also references from selected papers were scanned and relevant articles included.

High salt loading induces urinary storage dysfunction via upregulation of epithelial sodium channel alpha in the bladder epithelium in Dahl salt-sensitive rats

We aimed to investigate whether high salt intake affects bladder function via epithelial sodium channel (ENaC) by using Dahl salt-resistant (DR) and salt-sensitive (DS) rats. Bladder weight of DR + high-salt diet (HS, 8% NaCl) and DS + HS groups were significantly higher than those of DR + normal-salt diet (NS, 0.3% NaCl) and DS + NS groups after one week treatment. We thereafter used only DR + HS and DS + HS group. Systolic and diastolic blood pressures were significantly higher in DS + HS group than in DR + HS group after the treatment period. Cystometrogram showed the intercontraction intervals (ICI) were significantly shorter in DS + HS group than in DR + HS group during infusion of saline. Subsequent infusion of amiloride significantly prolonged ICI in DS + HS group, while no intra-group difference in ICI was observed in DR + HS group. No intra- or inter-group differences in maximum intravesical pressure were observed. Protein expression levels of ENaCα in the bladder were significantly higher in DS + HS group than in DR + HS group. ENaCα protein was localized at bladder epithelium in both groups. In conclusion, high salt intake is considered to cause urinary storage dysfunction via upregulation of ENaC in the bladder epithelium with salt-sensitive hypertension, suggesting that ENaC might be a candidate for therapeutic target for urinary storage dysfunction.

Novel selective, potent naphthyl TRPM8 antagonists identified through a combined ligand- and structure-based virtual screening approach

Transient receptor potential melastatin 8 (TRPM8), a nonselective cation channel, is the predominant mammalian cold temperature thermosensor and it is activated by cold temperatures and cooling compounds, such as menthol and icilin. Because of its role in cold allodynia, cold hyperalgesia and painful syndromes TRPM8 antagonists are currently being pursued as potential therapeutic agents for the treatment of pain hypersensitivity. Recently TRPM8 has been found in subsets of bladder sensory nerve fibres, providing an opportunity to understand and treat chronic hypersensitivity. However, most of the known TRPM8 inhibitors lack selectivity, and only three selective compounds have reached clinical trials to date. Here, we applied two virtual screening strategies to find new, clinics suitable, TRPM8 inhibitors. This strategy enabled us to identify naphthyl derivatives as a novel class of potent and selective TRPM8 inhibitors. Further characterization of the pharmacologic properties of the most potent compound identified, compound 1, confirmed that it is a selective, competitive antagonist inhibitor of TRPM8. Compound 1 also proved itself active in a overreactive bladder model in vivo. Thus, the novel naphthyl derivative compound identified here could be optimized for clinical treatment of pain hypersensitivity in bladder disorders but also in different other pathologies.

Effects of nitric oxide inhibitors in mice with bladder outlet obstruction

PURPOSE

To investigate the lower urinary tract changes in mice treated with L-NAME, a non-selective competitive inhibitor of nitric oxide synthase (NOS), or aminoguanidine, a competitive inhibitor of inducible nitric oxide synthase (iNOS), after 5 weeks of partial bladder outlet obstruction (BOO), in order to evaluate the role of constitutive and non-constitutive NOS in the pathogenesis of this experimental condition.

MATERIALS AND METHODS

C57BL6 male mice were partially obstructed and randomly allocated into 6 groups: Sham, Sham + L-NAME, Sham + aminoguanidine, BOO, BOO + L-NAME and BOO + aminoguanidine. After 5 weeks, bladder weight was obtained and cystometry and tissue bath contractile studies were performed.

RESULTS

BOO animals showed increase of non-voiding contractions (NVC) and bladder capacity, and also less contractile response to Carbachol and Electric Field Stimulation. Inhibition of NOS isoforms improved bladder capacity and compliance in BOO animals. L-NAME caused more NVC, prevented bladder weight gain and leaded to augmented contractile responses at muscarinic and electric stimulation. Aminoguanidine diminished NVC, but did not avoid bladder weight gain in BOO animals and did not improve contractile responses.

CONCLUSION

It can be hypothesized that chronic inhibition of three NOS isoforms in BOO animals leaded to worsening of bladder function, while selective inhibition of iNOS did not improve responses, what suggests that, in BOO animals, alterations are related to constitutive NOS.

Do rats have orgasms?

BACKGROUND

Although humans experience orgasms with a degree of statistical regularity, they remain among the most enigmatic of sexual responses; difficult to define and even more difficult to study empirically. The question of whether animals experience orgasms is hampered by similar lack of definition and the additional necessity of making inferences from behavioral responses.

METHOD

Here we define three behavioral criteria, based on dimensions of the subjective experience of human orgasms described by Mah and Binik, to infer orgasm-like responses (OLRs) in other species: 1) physiological criteria that include pelvic floor and anal muscle contractions that stimulate seminal emission and/or ejaculation in the male, or that stimulate uterine and cervical contractions in the female; 2) short-term behavioral changes that reflect immediate awareness of a pleasurable hedonic reward state during copulation; and 3) long-term behavioral changes that depend on the reward state induced by the OLR, including sexual satiety, the strengthening of patterns of sexual arousal and desire in subsequent copulations, and the generation of conditioned place and partner preferences for contextual and partner-related cues associated with the reward state. We then examine whether physiological and behavioral data from observations of male and female rats during copulation, and in sexually-conditioned place- and partner-preference paradigms, are consistent with these criteria.

RESULTS

Both male and female rats display behavioral patterns consistent with OLRs.

CONCLUSIONS

The ability to infer OLRs in rats offers new possibilities to study the phenomenon in neurobiological and molecular detail, and to provide both comparative and translational perspectives that would be useful for both basic and clinical research.

Expert Panel Recommendations on Lower Urinary Tract Health of Women Across Their Life Span

Urologic and kidney problems are common in women across their life span and affect their daily life, including physical activity, sexual relations, social life, and future health. Urological health in women is still understudied and the underlying mechanisms of female urological dysfunctions are not fully understood. The Society for Women's Health Research (SWHR^®) recognized the need to have a roundtable discussion where researchers and clinicians would define the current state of knowledge, gaps, and recommendations for future research directions to transform women's urological health. This report summarizes the discussions, which focused on epidemiology, clinical presentation, basic science, prevention strategies, and efficacy of current therapies. Experts around the table agreed on a set of research, education, and policy recommendations that have the potential to dramatically increase awareness and improve women's urological health at all stages of life.

Fourteen-day administration of corticosterone may induce detrusor overactivity symptoms

Introduction and hypothesis

Epidemiological studies demonstrated that patients suffering from overactive bladder often present with different mental problems, amongst which depression is the most frequently observed. The main goal of our study was to check if the repeated administration of corticosterone (CORT) is able to evoke the depressive-like behaviour and detrusor overactivity (DO) symptoms in rats. Moreover, we investigated whether the acute administration of common antidepressants (imipramine, 30 mg/kg, and fluoxetine, 15 mg/kg), antimuscarinic (oxybutynin chloride, 0.5 mg/kg) or CRF₁ (SN 003, 1 mg/kg) antagonists has an impact on the cystometric parameters, behaviour in the Porsolt test, and overall locomotor activity of animals exposed to CORT.

Methods

The experiments were carried out on female Wistar rats. All applied surgical and histopathology procedures, cystometric investigations, locomotor activity and forced swim measurements have been fully described in the published literature.

Results

Fourteen-day administration of CORT may induce both depressive and DO symptoms in rats, which are reversed by the inhibition of CRF₁ receptors.

Conclusions

It seems that the CRF₁ receptor could be an interesting target for overactive bladder pharmacotherapy, particularly in patients with co-existing depression.

An animal model of detrusor overactivity induced by depression

INTRODUCTION

Depression is frequently found in patients suffering from overactive bladder. The aim of the study was to verify whether the 13-cis-retinoic acid, a synthetic retinoid used in the treatment of acne, which was proven to induce depressive changes in both humans and animals, can cause detrusor overactivity symptoms in conscious rats.

METHODS

In order to assess the 13-cis-retinoic acid impact on the behavioural parameters, after 6weeks of intraperitoneal administration of retinoid in a dose of 1mg/kg/day, a forced swim test and cystometry were performed, and the locomotor activity of animals was assessed. The control group received a mixture of DMSO and physiological saline at a 1:1 ratio.

RESULTS

13-cis-retinoic acid caused cystometric parameter changes analogous to those observed in people with a urodynamic diagnosis of detrusor overactivity. The retinoid caused also an extension of the immobility time in the forced swim test which is consistent with increased depression-related behaviour, with no impact on the locomotor activity of rats. The intravenous administration of solifenacin succinate in a single dose of 0.03mg/kg turned out to reverse changes in the cystometric parameters modified by 13-cis-retinoic acid treatment. The histopathological analysis of bladders did not show any lesions in the upper layer of the umbrella cells, urothelium or muscles. The retinoid concentration level achieved in the animals tested turned out to be identical to that occurring in humans.

DISCUSSION

13-cis-retinoic acid can induce detrusor overactivity symptoms that are reversed by solifenacin succinate.

Assessment of penile erection methods in rhesus macaques to model pharmacokinetics of antiretroviral drugs and penile infection with simian immunodeficiency virus

BACKGROUND

An established macaque model to assess HIV interventions against penile transmission is currently not available. Physiological changes during penile erections may affect susceptibility to infection and drug pharmacokinetics (PK). Here, we identify methods to establish erections in macaques to evaluate penile transmission, PK, and efficacy under physiologic conditions.

METHODS

Penile rigidity and length were evaluated in eight rhesus macaques following rectal electrostimulation (RES), vibratory stimulation (VS), or pharmacological treatment with Sildenafil Citrate (Viagra) or Alprostadil.

RESULTS

Rectal electrostimulation treatment increased penile rigidity (>82%) and length (2.5 ± 0.58 cm), albeit the response was transient. In contrast, VS alone or coupled with Viagra or Alprostadil failed to elicit an erection response.

CONCLUSION

Rectal electrostimulation treatment elicits transient but consistent penile erections in macaques. High rigidity following RES treatment demonstrates increased blood flow and may provide a functional model for penile PK evaluations and possibly simian immunodeficiency virus (SIV) transmission under erect conditions.

Therapeutic Potential of Human Chorionic Gonadotropin Against Overactive Bladder

Overactive bladder (OAB) is a common form of urinary incontinence, resulting from spontaneous and random contractions of the urinary bladder. The affected individuals have an uncontrollable urge to urinate and experience incontinence and nocturia, which can greatly reduce the quality of daily life. There are several drugs for the treatment, and all of them have serious side effects. The following findings suggested that human chorionic gonadotropin (hCG) has a therapeutic potential that is worth investigating for the treatment of OAB. The finding are (1) human detrusor muscle contains hCG receptors, (2) detrusor muscle becomes quiescent during pregnancy, (3) hCG can inhibit detrusor muscle contractions induced by cholinergic stimulation in rats, and (4) hCG can mimic the anticholinergic drug on detrusor muscle contractions.

A new model of detrusor overactivity in conscious rats induced by retinyl acetate instillation

INTRODUCTION

A credible animal overactive bladder model used in basic research is an indispensable harbinger of safe and ethical clinical trials on human subjects. Our objective was to develop a new animal model of a hyperactive bladder that will be void of inflammatory urothelium lesions and display significant sensitivity to muscarinic receptor antagonists.

METHODS

To examine the influence of 0.75% retinyl acetate solution on cystometric parameters, it was infused into the bladder for 5min. Cystometric studies with physiological saline were performed in conscious unrestrained rats 3days later. To examine the influence of retinyl acetate, acetic acid or cyclophosphamide on morphology of urinary bladders, the bladders were subjected to histopathological examination.

RESULTS

We demonstrated that in rats subject to previous 5-minute bladder instillations with retinyl acetate, an increase of basal pressure, threshold pressure, micturition voiding pressure, bladder contraction duration, relaxation time, detrusor overactivity index, nonvoiding contraction frequency and amplitude occurs. On the other hand, a decrease in voided volume, post-void residual, volume threshold, voiding efficiency, intercontraction interval, bladder compliance and volume threshold to elicit nonvoiding contractions was observed. Administration of oxybutynin chloride (0.5mg/kg, i.v.) reversed changes of cystometric parameters evoked by retinyl acetate. Contrary to acetic acid and cyclophosphamide, bladders subjected to retinyl acetate infusion had no signs of bladder inflammation.

DISCUSSION

The results obtained indicate that transient infusion of 0.75% retinyl acetate can induce detrusor overactivity, which is often observed in patients with overactive bladder syndrome (OAB). In addition, it was demonstrated that stimulating afferent C-fibres using retinyl acetate did not induce evident histopathological inflammatory lesions in the urinary bladder wall. It appears that in the future this model can prove useful in gaining more knowledge on the pathophysiology of OAB, and contribute to the preparation of new, more effective options of OAB pharmacotherapy.

Stress urinary incontinence animal models as a tool to study cell-based regenerative therapies targeting the urethral sphincter

Urinary incontinence (UI) is a major health problem causing a significant social and economic impact affecting more than 200million people (women and men) worldwide. Over the past few years researchers have been investigating cell therapy as a promising approach for the treatment of stress urinary incontinence (SUI) since such an approach may improve the function of a weakened sphincter. Currently, a diverse collection of SUI animal models is available. We describe the features of the different models of SUI/urethral dysfunction and the pros and cons of these animal models in regard to cell therapy applications. We also discuss different cell therapy approaches and cell types tested in preclinical animal models. Finally, we propose new research approaches and perspectives to ensure the use of cellular therapy becomes a real treatment option for SUI.

Urethral orifice hyaluronic acid injections: a novel animal model of bladder outlet obstruction

Background

We produced a novel model of bladder outlet obstruction (BOO) by periurethral injection of hyaluronic acid and compared the cystometric features, postoperative complications, and histopathological changes of that model with that of traditional open surgery.

Methods

Forty female Sprague-Dawley rats were divided into three groups. Fifteen rats were subcutaneously injected with 0.2 ml hyaluronic acid at 5, 7, and 12 o’clock around the urethral orifice. Another fifteen rats underwent traditional open partial proximal urethral obstruction surgery, and 10 normal rats used as controls. After 4 weeks, filling cystometry, postoperative complications, and histopathological features were evaluated in each group. Three rats were also observed for 12 weeks after hyaluronic acid injection to evaluate the long-term effect.

Results

Hyaluronic acid periurethral injection caused increased maximum cystometric capacity, maximum bladder pressure, micturition interval, and post-void residual urine volume compared with control (p < 0.01). The injection group had significantly shorter operative time, less incidence of incision infection and bladder stone formation compared with the surgery group (p < 0.01). Hematoxylin and eosin (HE) staining showed suburothelial and interstitial hyperemia edema and smooth muscle hypertrophy in both injection and surgery bladders; these were not observed in the control group. Bladder weight and thickness of smooth muscle in the injection and surgery groups were significantly greater than those in the control group (p < 0.01). Urethral epithelial hyperplasia and lamina propria inflammation were observed in the surgery group but not in the injection or control groups. Rats periurethrally injected hyaluronic acid were stable the compound was not fully absorbed in any rat after 12 weeks.

Conclusions

Hyaluronic acid periurethral injection generates a simple, effective, and persistent animal model of BOO with lower complications, compared with traditional surgery.

Telemetric monitoring of bladder function in female Göttingen minipigs

OBJECTIVES

To generate real-time radio-telemetric urodynamic reference data of maximum detrusor pressure (Pdet max ), maximum flow rate (Qmax) and estimated grade of infravesical obstruction, as well as duration of detrusor contraction (DOC), in female Göttingen minipigs and to describe translational aspects of the use of Göttingen minipigs for urological research.

MATERIALS AND METHODS

A telemetric transmitter was implanted into five female Göttingen minipigs, and 24 h measurements in metabolic cages were taken. Through operator-based analysis, synchronized real-time radio-telemetric cystometric data with flowmetric data and video sequences were used to determine voiding detrusor contractions (VCs) and non-voiding detrusor contractions (NVCs). Furthermore, data from telemetric natural-filling cystometry from free-moving and restricted maintenance conditions were compared for potential differences.

RESULTS

The median (range) Pdet max of VCs was 120.6 (21.0-370.0) cmH2 O and, therefore, significantly different from that of NVCs (64.60 [20.4-280.6 cmH2 O] cm H2 O). Intraindividual comparison of minipig data revealed great differences in voiding contractions. The effects of limited movement on VCs were analysed and showed significantly higher Pdet max and lower DOC than in free-moving conditions.

CONCLUSION

The presented data can be used for the development of telecystometric implanted minipig models, to investigate changes of detrusor function such as under- or overactivity, and might serve as model for bladder changes occurring with iatrogenic bladder outlet obstruction (BOO) or different therapeutic options for overactive bladder. Radio-telemetric real-time natural filling and voiding cystometries are feasible, reproducible in non-anaesthetized minipigs with free or limited movement and can give new insights into circadian behaviour and physiological and pathological bladder function.

Micturition in Göttingen minipigs: first reference in vivo data for urological research and review of literature

One possible symptom of overactive bladder (OAB) is urinary incontinence, which is generally considered to be an age-associated disease and which is rapidly increasing with demographic changes. Rodent models are commonly used for the investigation of lower urinary tract functions, although the use of these species has limitations in several translational aspects. In biomedical research and preclinical toxicology, Göttingen minipigs are used increasingly. But in urological research, only few data are available for Göttingen minipigs. To the best of our knowledge, this study is one of the first to provide reference data of micturition in female Göttingen minipigs. Micturition frequency and volumes were monitored and analyzed in five female Göttingen minipigs. Voided volume was 520 ± 383 mL (mean ± standard deviation of mean [SD]) and micturition frequency 6.17 ± 3.68 (mean ± SD). We also performed a review of the literature to compare our data with data from different species (humans, pigs, rats and mice). Our findings revealed that micturition volume and frequency of Göttingen minipigs are more comparable with that of humans, leading to the conclusion that Göttingen minipigs may be the better choice for translational research in different research fields, such as urology, neurology and nephrology, etc. The provision of in vivo reference values meets with the 3R concept of 'reduction, refinement and replacement' of laboratory animals, because they allow comprehensive statistical power calculations (reduction), planning of telemetric approaches (refinement), and generation of computer-based modulation for the development of intravesical drug delivery systems (replacement).

Animal models of erectile dysfunction

Animal models have contributed to a great extent to understanding and advancement in the field of sexual medicine. Many current medical and surgical therapies in sexual medicine have been tried based on these animal models. Extensive literature search revealed that the compiled information is limited. In this review, we describe various experimental models of erectile dysfunction (ED) encompassing their procedures, variables of assessment, advantages and disadvantages. The search strategy consisted of review of PubMed based articles. We included original research work and certain review articles available in PubMed database. The search terms used were “ED and experimental models,” “ED and nervous stimulation,” “ED and cavernous nerve stimulation,” “ED and central stimulation,” “ED and diabetes mellitus,” “ED and ageing,” “ED and hypercholesteremia,” “ED and Peyronie's disease,” “radiation induced ED,” “telemetric recording,” “ED and mating test” and “ED and non-contact erection test.”

Pathophysiology and animal modeling of underactive bladder

While the symptomology of underactive bladder (UAB) may imply a primary dysfunction of the detrusor muscle, insights into pathophysiology indicate that both myogenic and neurogenic mechanisms need to be considered. Due to lack of proper animal models, the current understanding of the UAB pathophysiology is limited, and much of what is known about the clinical etiology of the condition has been derived from epidemiological data. We hereby review current state of the art in the understanding of the pathophysiology of and animal models used to study the UAB.

[TECAR therapy for Peyronie’s disease: a phase-one prospective study. Great evidence in patients with erectile dysfunction]

Our phase-one prospective study wants to evaluate the safety and tolerability of TECAR therapy in the treatment of Peyronie’s disease. From June 2011 to September 2012 we enrolled 70 patients. Each patient had been previously subjected to andrological examination, to a questionnaire for the evaluation of IPP and ED, and the SF-36 (V1) for the evaluation of the general state of health. The evaluation of pain was made using the VAS scale of pain. Every patient was subjected to TECAR treatment of the fibrotic plaque (both in resistive mode and in capacitive mode) for a total of three sessions carried out on consecutive days. We recorded a good compliance by patients; none of them reported side effects. Pain was decreased by the technique in 80% of the cases.The whole sample completed the study. Surprisingly enough those patients who complained also of erectile dysfunction, reported an improvement in sexual potency.

ADX71441, a novel, potent and selective positive allosteric modulator of the GABA(B) receptor, shows efficacy in rodent models of overactive bladder

BACKGROUND AND PURPOSE

The GABAB receptor agonist baclofen reduces urethral resistance and detrusor overactivity in patients with spasticity. However, baclofen's side effects limit its use for the treatment of overactive bladder (OAB). Here, we tested a novel GABAB positive allosteric modulator (PAM) ADX71441 in models of OAB in mice and guinea pigs.

EXPERIMENTAL APPROACH

Mice were left untreated or given (p.o.) vehicle (1% CMC), ADX71441 (1, 3, 10 mg kg(-1) ) or oxybutynin (100 mg kg(-1) ; Experiment 1) or vehicle (1% CMC), baclofen (1, 3, 6 mg kg(-1) ) or oxybutynin (Experiment 2). Treated mice were then overhydrated with water, challenged with furosemide, before being placed into micturition chambers and monitored for urinary parameters. In anaesthetized guinea pigs, intravesical infusion of acetic acid was used to induce OAB and the effects of ADX71441 (1, 3 mg kg(-1) ) or baclofen (1 mg kg(-1) ), administered i.v., on cystometric parameters were monitored.

KEY RESULTS

In mice, 10 mg kg(-1) ADX71441 increased urinary latencies, reduced the number of urinary events and the total and average urinary volumes. In guinea pigs, ADX71441 (1 and 3 mg kg(-1) ) increased the intercontraction interval (ICI) and bladder capacity (BC), and reduced micturition frequency (MF) compared to vehicle. At 3 mg kg(-1) ADX71441 completely inhibited the micturition reflex and induced overflow incontinence in five out of 10 animals. Baclofen slightly increased ICI and BC and reduced MF.

CONCLUSION AND IMPLICATIONS

Our findings demonstrate, for the first time, that a GABAB PAM has potential as a novel approach for the treatment of OAB.

Age-related changes in the concentration of elastic fibers in different regions of the rabbit penis

PURPOSE

To investigate whether elastic fiber content in the corpus cavernosum (CC), corpus spongiosum (CS) and tunica albuginea (TA) of the rabbit penis undergoes modifications with age.

METHODS

Rabbits were sacrificed, in groups of ten animals each, at 30, 120, 240, and 730 days of age. Histological sections were obtained from the penile middle shaft and were stained with Weigert's resorsin fuchsin. The content of elastic fibers was determined using stereological methods, and was expressed as volume fraction.

RESULTS

At 730 days of age, elastic fiber content was increased by 54% (p<0.004), 78% (p<0.004), and 87% (p<0.004) in the TA, CC, and CS, respectively, compared with animals aged 30 days. After 30 days of age, the concentration gradually and significantly increased until 240 days of age. In 730-day old animals, the concentration, compared with the previous age group, was unchanged in the CC and decreased by 20% (p<0.004) in the TA.

CONCLUSIONS

Elastic fiber contents in the rabbit penis correlate with properties of penile tissues. Although after one month of age there is a gradual increase in these concentrations, in two-year old animals this trend is interrupted, which suggests that this could be an early alteration due to senescence.

An animal study to compare the degree of the suppressive effects on the afferent pathways of micturition between tamsulosin and sildenafil

Background

Tamsulosin, an α1-adrenoceptor antagonist, and sildenafil, a phosphodiesterase (PDE) inhibitor, are reported to improve lower urinary tract symptoms including overactive bladder (OAB). This study is aimed at investing the effects of tamsulosin and sildenafil and comparing the degree of the suppressive effects on the afferent pathways of micturition between them using an animal model of OAB, the spontaneously hypertensive rat (SHR).

Results

The cystometric parameters, the basal pressure and duration of bladder contraction, were significantly increased in the SHR group as compared with the Wistar-Kyoto (WKY) group. The intercontraction interval also significantly decreased in the SHR group. In the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group, however, the basal pressure and duration were significantly reduced and the intercontraction interval was significantly prolonged. Moreover, the degree of the expression of c-Fos and NGF was significantly higher in the SHR group as compared with the WKY group. But it was significantly reduced in the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group. Furthermore, tamsulosin had a higher degree of effect as compared with sildenafil.

Conclusions

In conclusion, α1-adrenergic receptor antagonists and PDE-5 inhibitors may have an effect in improving the voiding functions through an inhibition of the neuronal activity in the afferent pathways of micturition.

Descrição morfológica e morfométrica da glândula vesicular de cobaias durante o desenvolvimento pós-natal

Glândulas vesiculares são essenciais para a reprodução, pois suas secreções afetam a função espermática. Cobaias (Cavia porcellus) são um excelente modelo experimental para estudo destas glândulas, contudo não existem dados morfológicos e morfométricos durante seu desenvolvimento. Neste estudo a morfologia (projeções das pregas (PP) e altura das células epiteliais (AE) da túnica mucosa) e a morfometria (massa (MG), volume (VG), comprimento (CG), largura das porções cranial (LCR), média (LM) e caudal (LCA)) das glândulas vesiculares foram determinadas em cobaios (N= 25) com uma (S1), três (S3), cinco (S5), oito (S8) e onze (S11) semanas de idade (N=5/grupo de idade). Em adição massa (MC), comprimento (CC) e altura (AC) corporais e o índice organo-somático (IOS) foram também determinados e o coeficiente de correlação (r) estabelecido entre as variáveis. As glândulas restringiam-se a cavidade pélvica e tinham seu interior repleto de uma massa semi-sólida e, após a S8, ocuparam também a cavidade abdominal e tiveram o conteúdo aumentado significativamente. A túnica mucosa era pregueada e forrada de um epitélio simples colunar. MC, CC e AC aumentaram continuamente com a idade. MG, VG, CG e LCA não se alteraram da S1 a S5 e aumentaram na S8; enquanto que MF, VG e LCA também aumentaram na S11. IOS e PP aumentaram na S8 e S11 e AE na S5, S8 e S11. Houve (r) significativo entre a idade, Bc e MFg,; IOS e MG na S8 e S11; idade e PP; idade e AE e entre PP e AE. Em conclusão, as glândulas vesiculares de cobaios seguiram o padrão morfológico observado em ratos e hamsters, mas diferiram em alguns aspectos de outros histricomorfos, podendo ser utilizadas como modelo experimental e seu desenvolvimento morfológico e morfométrico podem ser divididos em três fases: da S1 a S5, quando são discretos; da S6 a S8 de idade, quando são acentuados de maneira geral e após a S8, quando há incremento intenso da capacidade secretória.

5-Hydroxytryptamine-induced bladder hyperactivity via the 5-HT2A receptor in partial bladder outlet obstruction in rats

We investigated the effects of partial bladder outlet obstruction (BOO) on the function and gene expression of 5-hydroxytryptamine (5-HT) receptor subtypes in rat bladder. Isometric contractions of the isolated bladders from sham-operated control and BOO rats were examined. The contractile responses to 5-HT were significantly increased in BOO rat bladder strips, while the responses to KCl, carbachol, or phenylephrine were not different from the control. The 5-HT-induced hypercontraction in BOO rat bladder strips was inhibited by ketanserin, a 5-HT(2A) receptor antagonist. The contractile responses to 5-HT in bladder strips were not affected by urothelium removal from the intact bladder. The gene expression of 5-HT receptor subtypes in the bladders was analyzed by RT-PCR. The mRNA expression of the 5-HT(2A), 5-HT(2B), 5-HT(2C), 5-HT(4), and 5-HT(7) receptors was detected in both the control and BOO rat bladders. Quantitative RT-PCR analysis showed there was a significant increase of 5-HT(2A) receptor mRNA in the BOO rat bladder compared with the control bladder. On the other hand, the gene expression of the 5-HT(4) receptor was not changed in the BOO rat bladder. These results suggest that the increased contractile responses to 5-HT in BOO rat bladder may be partly caused by 5-HT(2A) receptor upregulation in the detrusor smooth muscles.

Effects of coenzyme Q10 on bladder dysfunction induced by chronic bladder ischemia in a rat model

PURPOSE

We investigated the protective effects of coenzyme Q10 on bladder dysfunction in a rat model of atherosclerosis induced chronic bladder ischemia.

MATERIALS AND METHODS

A total of 24 male Sprague-Dawley® rats at age 16 weeks were divided into 4 groups of 6 each, including group 1--untreated, sham operated rats, group 2--coenzyme Q10 treated, sham operated rats, group 3--untreated rats with chronic bladder ischemia and group 4--coenzyme Q10 treated rats with chronic bladder ischemia. Groups 3 and 4 received an endothelial injury to the iliac arteries and were fed a 2% cholesterol diet for 8 weeks. Groups 2 and 4 were treated with coenzyme Q10 and the others were treated with vehicle for 4 weeks. Eight weeks postoperatively we performed continuous in vivo cystometry, an in vitro detrusor muscle strip study and a malondialdehyde assay. Histological examination of the bladder walls and iliac arteries was also done.

RESULTS

In vivo cystometry revealed that coenzyme Q10 administration after the induction of chronic bladder ischemia prolonged micturition frequency and the intercontraction interval, and increased bladder capacity compared to those in untreated rats with chronic bladder ischemia. In the detrusor muscle strip study coenzyme Q10 administration after the induction of chronic bladder ischemia increased contractile responses compared to those in untreated rats with chronic bladder ischemia. Rats with chronic bladder ischemia also showed higher malondialdehyde in bladder tissue and serum than the other groups. Chronic bladder ischemia induced submucosal fibrosis of the bladder walls and a degenerative change in the blood vessel tunical media, as shown on histological examination.

CONCLUSIONS

Our study suggests that coenzyme Q10 acts as an antioxidant to protect bladder function in this chronic bladder ischemia model.

External urethral sphincter motor unit recruitment patterns during micturition in the spinally intact and transected adult rat

In the rat, external urethral sphincter (EUS) activation during micturition consists of three sequential phases: 1) an increase in tonic EUS activity during passive filling and active contraction of the bladder (guarding reflex), 2) synchronized phasic activity (EUS bursting) associated with voiding, and 3) sustained tonic EUS activity that persists after bladder contraction. These phases are perturbed following spinal cord injury. The purpose of the present study was to characterize individual EUS motor unit (MU) patterns during micturition in the spinally intact and transected adult rat. EUS MU activity was recorded from either the L5 or L6 ventral root (intact) or EUS muscle (transected) during continuous flow cystometry in urethane-anesthetized adult female Sprague-Dawley rats. With the use of bladder pressure threshold and timing of activation, four distinct patterns of EUS MU activity were identified in the intact rat: low threshold sustained, medium/high threshold sustained, medium/high threshold not sustained, and burst only. In general, these MUs displayed little frequency modulation during active contraction, generated high-frequency bursts of action potentials during EUS bursting, and varied in terms of the duration of sustained tonic activity. In contrast, three general patterns of EUS MU activity were identified in the transected rat: low threshold, medium threshold, and high threshold. These MUs exhibited considerable frequency modulation during active contraction of the bladder, no bursting behavior and little to no sustained firing. The prominent frequency modulation of EUS MUs is likely due to the enhanced guarding reflex seen in EUS whole muscle electromyogram recordings in transected rats (D'Amico SC, Schuster IP, Collins WF 3rd. Exp Neurol 228: 59–68, 2011). In addition, EUS MU recruitment in transected rats more closely followed predictions by the size principle than in intact rats. This may reflect the influence of local synaptic circuits or intrinsic properties of EUS motoneurons that are active in intact rats but attenuated or absent in transected rats.

Resiniferatoxin and tetrodotoxin induced NPY and TH immunoreactivity changes within the paracervical ganglion neurons supplying the urinary bladder

Both resiniferatoxin (RTX) and tetrodotoxin (TTX) have been reported to be effective in several urinary bladder dysfunction clinical trials. The aim of this study was to establish the effect of intravesical administration of RTX and TTX on neuropeptides Y (NPY) and tyrosine hydroxylase (TH) relationship in the paracervical ganglion (PCG) neurons supplying the urinary bladder in the pig. TH is an enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to dihydroxyphenylalanine (DOPA) and is used as a marker of catecholaminergic neurons. NPY augments the vasoconstrictor effects of noradrenergic neurons, and is involved in pathophysiological processes as a neuromodulator. To identify the PCG neurons supplying urinary bladder Fast Blue (FB) was injected into the bladder wall prior to intravesical RTX or TTX administration. Consequent application of immunocytochemical methods revealed that in control group 64.08 % of FB-positive PCG neurons contain NPY and 4.25 % TH. Intravesical infusion of RTX resulted upregulation of the NPY-IR neurons to 82.97 % and TH-IR to 43.78 %. Also administration of TTX induced further increase number of TH-IR neurons to 77.49 % but induced decrease number of NPY-IR neurons to 57.45 %. Both neurotoxins affect chemical coding of the PCG neural somata supplying urinary bladder, but the effects of their action are different. This results shed light on possible involvement of RTX and TTX on curing tissue, and potentially could help us to broaden our neurourological armamentarium.