3R-Refinement principles: elevating rodent well-being and research quality

This review article delves into the details of the 3R-Refinement principles as a vital framework for ethically sound rodent research laboratory. It highlights the core objective of the refinement protocol, namely, to enhance the well-being of laboratory animals while simultaneously improving the scientific validity of research outcomes. Through an exploration of key components of the refinement principles, the article outlines how these ethics should be implemented at various stages of animal experiments. It emphasizes the significance of enriched housing environments that reduce stress and encourage natural behaviors, non-restraint methods in handling and training, refined dosing and sampling techniques that prioritize animal comfort, the critical role of optimal pain management and the importance of regular animal welfare assessment in maintaining the rodents well-being. Additionally, the advantages of collaboration with animal care and ethics committees are also mentioned. The other half of the article explains the extensive benefits of the 3R-Refinement protocol such as heightened animal welfare, enhanced research quality, reduced variability, and positive feedback from researchers and animal care staff. Furthermore, it addresses avenues for promoting the adoption of the protocol, such as disseminating best practices, conducting training programs, and engaging with regulatory bodies. Overall, this article highlights the significance of 3R-Refinement protocol in aligning scientific advancement with ethical considerations along with shaping a more compassionate and responsible future for animal research.

Efficacy and Safety of Water-Free Lipid Formulation System Containing Calcipotriol Against Psoriasis Vulgaris

Calcipotriol, a vitamin D analogue is widely used in the treatment of psoriasis. However, poor adherence to topical therapy has led to an ineffective use of the medication and built a barrier to the treatment's success. A water-free lipid-based formulation system has been developed to improve dosage and cosmetic properties along with patient compliance. This study was conducted to evaluate the efficacy and cutaneous safety of water-free lipid-based formulations containing calcipotriol (50 μg/g) as compared to their corresponding vehicles and marketed calcipotriol formulations in a psoriasis plaque test. In total, 24 subjects with chronic psoriasis vulgaris were enrolled in this single-center, randomized, vehicle, and comparator-controlled clinical trial and treated once daily over a 12-day period (10 applications). The anti-psoriatic effect was evaluated by sonographic measurement of psoriatic infiltrate and investigators' clinical efficacy assessments. The mean reduction in psoriatic infiltrate from baseline to day 12 (end of trial) with lipid-based calcipotriol formulations (-34% and -37%) was statistically significant (P<0.0001) when compared to their corresponding vehicles (6% and -4%) but not when compared with marketed calcipotriol solution and cream (-34% and -49% respectively). Mean total clinical assessment scores of these lipid-based calcipotriol formulations (1.7 each) were between those of the two comparators - greater than marketed calcipotriol solution (1.3) but lower than cream (2.0). Overall, nine mild non-serious treatment-emergent adverse effects related to all calcipotriol formulations were reported in four subjects, but all recovered at the follow-up visit. Therefore, novel lipid-based formulations of calcipotriol were clearly more efficacious than their corresponding vehicles and considered as safe therapy against psoriasis vulgaris. J Drugs Dermatol. 2023;22(2):197-202. doi:10.36849/JDD.7151Citation: Holmbäck J, Carlsson A, Rinwa P. Efficacy and safety of water-free lipid formulation system containing calcipotriol against psoriasis vulgaris. J Drugs Dermatol. 2023;22(2):197-202. doi:10.36849/JDD.7151 &nbsp.

Preclinical development of sodium fusidate antibiotic cutaneous spray based on water-free lipid formulation system

Topical antibiotics are a key component in the management of mild to moderate skin and soft tissue infections. There are, however, concerns about the emerging bacterial resistance against topical antibacterial agents such as fusidic acid, due to the prolonged treatment period of its marketed dosage forms. Improving the efficacy of topical formulations could potentially shorten the treatment period and avoid the resistance growth. To provide a more effective drug delivery, a water-free lipid-based formulation system (AKVANO®) which can be applied by spraying, has been developed. In the current paper, different formulations containing sodium fusidate were evaluated for their in vitro skin permeability using artificial skin mimicking membranes and antibacterial properties using ex vivo and in vivo skin wound infection models. The novel formulations containing sodium fusidate showed a much higher skin permeation (up to 60% of nominal amount) than the commercially available Fucidin® cream (3%). These formulations also gave a significantly stronger antibacterial effect than Fucidin cream showing a clear dose-response relationship for the sodium fusidate content. A spray product based on the described formulation technology would therefore require a shorter treatment time and thereby lower the risk for the development of bacterial resistance. Spray administration of these formulations provides an even layer on the skin surface from which the solvent quickly evaporates and thereby facilitates a non-touch application where no rubbing is required.

AKVANO®: A Novel Lipid Formulation System for Topical Drug Delivery-In Vitro Studies

A novel formulation technology called AKVANO® has been developed with the aim to provide a tuneable and versatile drug delivery system for topical administration. The vehicle is based on a water-free lipid formulation where selected lipids, mainly phospholipids rich in phosphatidylcholine, are dissolved in a volatile solvent, such as ethanol. With the aim of describing the basic properties of the system, the following physicochemical methods were used: viscometry, dynamic light scattering, NMR diffusometry, and atomic force microscopy. AKVANO formulations are non-viscous, with virtually no or very minute aggregates formed, and when applied to the skin, e.g., by spraying, a thin film consisting of lipid bilayer structures is formed. Standardized in vitro microbiological and irritation tests show that AKVANO formulations meet criteria for antibacterial, antifungal, and antiviral activities and, at the same time, are being investigated as a non-irritant to the skin and eye. The ethanol content in AKVANO facilitates incorporation of many active pharmaceutical ingredients (>80 successfully tested) and the phospholipids seem to act as a solubilizer in the formulation. In vitro skin permeation experiments using Strat-M® membranes have shown that AKVANO formulations can be designed to alter the penetration of active ingredients by changing the lipid composition.

Demise of nociceptive Schwann cells causes nerve retraction and pain hyperalgesia

ABSTRACT

Recent findings indicate that nociceptive nerves are not "free", but similar to touch and pressure sensitive nerves, terminate in an end-organ in mice. This sensory structure consists of the nociceptive nerves and specialized nociceptive Schwann cells forming a mesh-like organ in subepidermis with pain transduction initiated at both these cellular constituents. The intimate relation of nociceptive nerves with nociceptive Schwann cells in mice raises the question whether defects in nociceptive Schwann cells can by itself contribute to pain hyperalgesia, nerve retraction, and peripheral neuropathy. We therefore examined the existence of nociceptive Schwann cells in human skin and their possible contribution to neuropathy and pain hyperalgesia in mouse models. Similar to mouse, human skin contains SOX10+/S100B+/AQP1+ Schwann cells in the subepidermal border that have extensive processes, which are intimately associated with nociceptive nerves projecting into epidermis. The ablation of nociceptive Schwann cells in mice resulted in nerve retraction and mechanical, cold, and heat hyperalgesia. Conversely, ablating the nociceptive nerves led to a retraction of epidermal Schwann cell processes, changes in nociceptive Schwann cell soma morphology, heat analgesia, and mechanical hyperalgesia. Our results provide evidence for a nociceptive sensory end-organ in the human skin and using animal models highlight the interdependence of the nerve and the nociceptive Schwann cell. Finally, we show that demise of nociceptive Schwann cells is sufficient to cause neuropathic-like pain in the mouse.

PAD2-Mediated Citrullination Contributes to Efficient Oligodendrocyte Differentiation and Myelination

Citrullination, the deimination of peptidylarginine residues into peptidylcitrulline, has been implicated in the etiology of several diseases. In multiple sclerosis, citrullination is thought to be a major driver of pathology through hypercitrullination and destabilization of myelin. As such, inhibition of citrullination has been suggested as a therapeutic strategy for MS. Here, in contrast, we show that citrullination by peptidylarginine deiminase 2 (PAD2) contributes to normal oligodendrocyte differentiation, myelination, and motor function. We identify several targets for PAD2, including myelin and chromatin-related proteins, implicating PAD2 in epigenomic regulation. Accordingly, we observe that PAD2 inhibition and its knockdown affect chromatin accessibility and prevent the upregulation of oligodendrocyte differentiation genes. Moreover, mice lacking PAD2 display motor dysfunction and a decreased number of myelinated axons in the corpus callosum. We conclude that citrullination contributes to proper oligodendrocyte lineage progression and myelination.

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PAD2 is increased upon OL differentiation

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OL differentiation is facilitated by PAD2-mediated chromatin remodeling in myelin genes

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PAD2 contributes to efficient myelination and motor and cognitive functions

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Nuclear and myelin proteins interact and are citrullinated by PAD2

Buspirone along with melatonin attenuates oxidative damage and anxiety-like behavior in a mouse model of immobilization stress

AIM

Stress is recognized to precipitate anxiety and related psychological problems characterized by a wide range of biochemical and behavioral changes. The present study was carried out to investigate the protective effects of melatonin and buspirone, and their combination, against six hours immobilization stress-induced, anxiety-like behavioral and oxidative damage in mice.

METHOD

Male Laca mice were pre-treated with melatonin (2.5, 5 mg·kg(-1)), buspirone (5, 10 mg·kg(-1)), and their combination for consecutive five days. On the 6(th) day, animals were immobilized for six hours, and thereafter various behavioral tests were performed followed by biochemical tests.

RESULTS

Immobilization stress significantly impaired body weight, locomotor activity, and caused anxiety-like behavior, along with increased oxidative damage. Pretreatment with melatonin and buspirone significantly improved the loss in body weight and locomotor activity, attenuated anxiety-like behavior (in both the mirror chamber and plus maze performance tasks), further restored the levels of brain total proteins, and caused antioxidant-like effects, as evidenced by reduced lipid peroxidation, nitrite concentration, and restoration of reduced glutathione and catalase activity, as compared to control animals. In addition, combination of melatonin (2.5, 5 mg·kg(-1)) with buspirone (5 mg·kg(-1)) significantly potentiated their protective effects, as compared to their effects individually.

CONCLUSION

The present study suggests that melatonin potentiates the beneficial effect of buspirone against immobilization stress-induced, anxiety-like behavioral and oxidative damage in mice possibly by involving a serotonergic mechanism.

Modulation of nitrergic signalling pathway by American ginseng attenuates chronic unpredictable stress-induced cognitive impairment, neuroinflammation, and biochemical alterations

Prolonged stress causes extensive loss of neurons leading to deficits in cognitive performance. Increasing evidence indicates that accumulation of intercellular messenger, nitric oxide (NO), plays a crucial role in the pathogenesis of memory disorders. American ginseng (AG) is known to show protection in different animal models of neurological diseases; however, its exact mechanism of action is not clearly understood. Therefore, the current study was designed to investigate the interaction of AG against chronic unpredictable stress (CUS)-associated behavioral and biochemical alterations and the probable role of nitrergic pathway in this effect. Male Laca mice were exposed to a series of stressors along with drug/vehicle treatment daily for 28 days. CUS paradigm caused significant impairment in both acquisition and retention memory as measured in Morris water maze and elevated plus maze task. This was coupled with alterations in oxidative stress markers, mitochondrial enzyme complex activities, pro-inflammatory cytokine (TNF-α), and acetylcholinesterase levels in the hippocampus as compared with naïve group. Besides, there was a marked increase in serum corticosterone levels. AG (100, 200 mg/kg; p.o.) treatment significantly improved cognitive impairment; reduced TNF-α, acetylcholinesterase, and corticosterone levels; and attenuated oxidative-nitrergic stress. Furthermore, pre-treatment of L-arginine (100 mg/kg; i.p.), a nitric oxide donor, with subeffective dose of AG (100 mg/kg; p.o.) reversed its protective effects. However, L-NAME (10 mg/kg, i.p.), a non-specific NO synthase inhibitor, potentiated the effects of AG. Our findings suggest that modulation of nitrergic signalling cascade is involved in the protective effects of AG against CUS-induced cognitive dysfunction, oxidative stress, and neuroinflammation.

Evaluation of sesamol and buspirone in stress induced anxiety in mice

Objectives:

The present study was designed to elucidate the effects of sesamol, buspirone and their combination in immobilization stress induced behavioral and biochemical alterations in mice.

Materials and Methods:

Male Laca mice (divided into 10 groups with 6 animals each) were pre-treated with sesamol (5 and 10 mg/kg; p.o.), buspirone (5 and 10 mg/kg; p.o.) and combination of sesamol (5 and 10 mg/kg; p.o.) with buspirone (5 mg/kg; p.o.) for consecutive five days. On the 6^th day, animals were immobilized for 6 h and various behavioral tests such as body weight, locomotor activity, mirror chamber test and elevated plus maze were carried out. Biochemical estimations such as lipid peroxidation and nitrite concentration, glutathione and catalase levels were done. Data was analyzed using One way ANOVA followed by Tukey's test (P < 0.05) was considered statistical significant.

Results:

Immobilization stress significantly (P < 0.05) impaired body weight, locomotor activity, induced anxiety like behavioral and oxidative damage as compared to naοve animal. Pretreatment with sesamol (5 and 10 mg/kg; p.o.) and buspirone (5 and 10 mg/ kg; p.o.) significantly (P < 0.05) improved body weight, locomotor activity, and anxiety like behavior in mirror chamber as well as plus maze performance tasks and anti-oxidant like effect as evidenced by reduced lipid peroxidation, nitrite concentration and restoration of reduced glutathione and catalase activity as compared to control animals. Further, co- administration of sesamol (5 and 10 mg/kg) with buspirone (5 mg/kg) significantly (P < .05) potentiated the anti anxiety effects as compared to their effects alone.

Conclusions:

The present study suggests that combination of sesamol and buspirone potentiated the antianxiety effects against anxiety induced by immobilization stress and oxidative damage in mice.

Quercetin along with piperine prevents cognitive dysfunction, oxidative stress and neuro-inflammation associated with mouse model of chronic unpredictable stress

Stress occurs in everyday life and persistence of it causes memory loss. Bioflavonoids like quercetin are reported to have poor bioavailability and limited therapeutic potential against stress induced neurological disorders. Therefore, the present study is an attempt to elucidate the therapeutic potency of combination of quercetin with piperine; a bioavailability enhancer against chronic unpredictable stress (CUS)-induced behavioral and biochemical alterations. Laca mice were subjected to a series of stressful events for a period of 28 days. Quercetin (20, 40 and 80 mg/kg, p.o.), piperine (20 mg/kg, p.o.) and their combinations were administered daily 30 min before CUS procedure. Piracetam (100 mg/kg, i.p.) served as a standard control. CUS caused impaired spatial navigation in Morris water maze test and poor retention in elevated plus maze task. Further, there was significant increase in brain oxidative stress markers and neuro-inflammation (TNF-α). This was coupled with marked rise in acetylcholinesterase and serum corticosterone levels. Co-administration of piperine with quercetin significantly elevated their potential to restore these behavioral, biochemical and molecular changes associated with mouse model of CUS. These results suggest that piperine enhances the neuroprotective effects of quercetin against CUS-induced oxidative stress, neuro-inflammation and memory deficits.

Suppression of neuroinflammatory and apoptotic signaling cascade by curcumin alone and in combination with piperine in rat model of olfactory bulbectomy induced depression

Objectives

Bilateral destruction of the olfactory bulbs is known to cause behavioral changes analogous to symptoms of depression. Curcumin, a traditional Indian spice is currently being investigated in different psychiatric problems including depression. Dietary phytochemicals are currently used as an adjuvant therapy to accelerate their therapeutic efficacy. Therefore, the present study is an attempt to elucidate the neuroprotective mechanism of curcumin and its co-administration with piperine against olfactory bulbectomy induced depression in rats.

Methods

Rats undergone olfactory bulbs ablations were analyzed after post-surgical rehabilitation period of 2 weeks. Animals were then treated with different doses of curcumin (100, 200 and 400 mg/kg; p.o.), piperine (20 mg/kg; p.o.) and their combination daily for another 2 weeks. Imipramine (10 mg/kg; i.p.) served as a standard control. Various behavioral tests like forced swim test (FST), open field behaviour and sucrose preference test (SPT) were performed, followed by estimation of biochemical, mitochondrial, molecular and histopathological parameters in rat brain.

Results

Ablation of olfactory bulbs caused depression-like symptoms as evidenced by increased immobility time in FST, hyperactivity in open field arena, and anhedonic like response in SPT along with alterations in mitochondrial enzyme complexes, increased serum corticosterone levels and oxidative damage. These deficits were integrated with increased inflammatory cytokines (TNF-α) and apoptotic factor (caspase-3) levels along with a marked reduction in neurogenesis factor (BDNF) in the brain of olfactory bulbectomized (OBX) rats. Curcumin treatment significantly and dose-dependently restored all these behavioral, biochemical, mitochondrial, molecular and histopathological alterations associated with OBX induced depression. Further, co-administration of piperine with curcumin significantly potentiated their neuroprotective effects as compared to their effects alone.

Conclusions

The present study highlights that curcumin along with piperine exhibits neuroprotection against olfactory bulbectomy induced depression possibly by modulating oxidative-nitrosative stress induced neuroinflammation and apoptosis.

Stress: Neurobiology, consequences and management

Stress, both physical and psychological, is attracting increasing attention among neuroresearchers. In the last 20 decades, there has been a surge of interest in the research of stress-induced manifestations and this approach has resulted in the development of more appropriate animal models for stress-associated pathologies and its therapeutic management. These stress models are an easy and convenient method for inducing both psychological and physical stress. To understand the behavioral changes underlying major depression, molecular and cellular studies are required. Dysregulation of the stress system may lead to disturbances in growth and development, and may this may further lead to the development of various other psychiatric disorders. This article reviews the different types of stress and their neurobiology, including the different neurotransmitters affected. There are various complications associated with stress and their management through various pharmacological and non-pharmacological techniques. The use of herbs in the treatment of stress-related problems is practiced in both Indian and Western societies, and it has a vast market in terms of anti-stress medications and treatments. Non-pharmacological techniques such as meditation and yoga are nowadays becoming very popular as a stress-relieving therapy because of their greater effectiveness and no associated side effects. Therefore, this review highlights the changes under stress and stressor and their impact on different animal models in understanding the mechanisms of stress along with their effective and safe management.

Pharmacological investigation of memory restorative effect of riluzole in mice

Objective:

Streptozotocin (STZ) and sodium nitrite (NaNO₂) treatment have been positively correlated with higher incidence of memory loss and experimental dementia. The present study was designed to investigate the potential of the Riluzole, an inhibitor of glutamatergic neurotransmission and activator of TWIK-Related K⁺ channels with incidences of memory deficits associated with dementia in mice.

Materials and Methods:

Dementia was induced in Swiss albino mice by intracerebroventricular STZ (ICV) and by subcutaneous NaNO₂ in separate groups of animals. Morris water maze was employed to assess learning and memory of the animals. Biochemical analysis of brain homogenate was performed so as to assess brain acetyl cholinesterase (AChE) activity. Brain thiobarbituric acid reactive species (TBARS) levels and reduced glutathione (GSH) levels were measured to assess total oxidative stress.

Results:

Treatment of ICV STZ and NaNO₂ produced a significant decrease in water maze performance of mice hence reflecting loss of learning and memory. Furthermore, higher levels of brain AChE activity and oxidative stress were observed in these animals. Administration of riluzole (5 and 10 mg/kg intraperitoneally) successfully attenuated memory deficits as well as ICV STZ- and NaNO₂ -induced changes in the levels of brain AChE, TBARS, and GSH.

Conclusion:

The memory restorative effects of riluzole in dementia may involve its multiple functions including anti-oxidative and anticholinesterase properties.