Omega-3 fatty acids are able to modulate the painful symptoms associated to cyclophosphamide-induced-hemorrhagic cystitis in mice

Cucumeropsis mannii seed oil shields against cyclophosphamide-induced hepatorenal toxicity by modulating redox imbalance and iNOS/IL-β1 signalling in rats

This study aimed to determine whether C. mannii seed oil (CMSO) could shield rats from cyclophosphamide-induced hepatorenal toxicity. The focus was on its antioxidant and anti-inflammatory properties. We randomly assigned thirty-six (36) male Wistar rats into six groups of six rats each. Groups A and B served as normal and negative controls, respectively. Group C, the standard control, was administered 300 mg/kg body weight (bw) of Omega 3 oil for 27 days, followed by 100 mg/kg bw of cyclophosphamide on day 28. Group D, E, and F received 5, 2.5, and 1.5 ml/kg b.w. of CMSO for 27 days, then 100 ml/kg b.w. of cyclophosphamide on day 28. We measured the body weights of the experimental rats every week. Rats of all groups were sacrificed on day 30 and collected blood for biochemical analysis using standard methods. The phytochemical constituents were determined by the spectrophotometric method. The phytochemical study of CMSO indicated the relative composition of constituents(mg/100g) as phenols (30 %), tannins (20 %), flavonoids (18 %), terpenoids (15 %), glycosides (10 %), alkaloids (5 %), and HCN (2 %) in Cucumeropsis mannii seed oil. When cyclophosphamide was given to Wistar albino rats, it greatly decreased the activities of catalase (CAT) and superoxide dismutase (SOD), but it increased the activities of iNOS and the levels of MDA and IL-1β. Cyclophosphamide increased ALT (52.3 U/L), AST (48.7 U/L), ALP (46.5 U/L), total bilirubin (1.4 mg/dL), conjugated bilirubin (0.8 mg/dL), creatinine (0.8 mg/dL), urea (45.6 mg/dL), and BUN (15.7 mg/dL), with a reduction in the albumin (4.8 g/dL) level. Cyclophosphamide administration also caused hepatocellular necrosis, inflammatory leukocyte infiltration, tubular necrosis, and proteinaceous deposits in Bowman's space in the kidney. However, combining CMSO and Omega 3 oils significantly restored the altered histology architecture, antioxidant, inflammatory markers, and liver and kidney function parameters to levels comparable to the normal group, thereby reducing the harmful effects of cyclophosphamide. This effect did not depend on the dose. These results suggest that CMSO, being an antioxidant and an anti-inflammatory, could potentially aid in preventing and treating hepatorenal toxicity resulting from cyclophosphamide.

The serotonin(5-HT)2A receptor is involved in the hypersensitivity of bladder afferent neurons in cyclophosphamide-induced cystitis

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic bladder inflammation characterized by the main symptoms of urinary frequency, urgency, and pelvic pain. The hypersensitivity of bladder afferent neurons is considered a significant pathophysiologic mechanism in IC/PBS. Serotonin (5-HT, 5-hydroxytryptamine) receptors are known to be involved in the regulation of the micturition reflex and hyperalgesia, but the effect of 5-HT receptors on cystitis remains unknown. In this study, a rat model of interstitial cystitis induced by intraperitoneal injection of cyclophosphamide (CYP) was used to investigate the role of 5-HT receptors on cystitis. The histology and urodynamics exhibited chronic cystitis and overactive bladder in CYP-treated rats. Notably, among 5-HT1A, 5-HT2A and 5-HT7 receptors, the expression of 5-HT2A receptor was significantly increased in bladder afferent neurons in CYP-treated rats. Intrathecal administration of the 5-HT2A receptor antagonist M100907 could alleviate bladder overactivity and hyperalgesia in CYP-induced cystitis rats. Neuronal calcium imaging of bladder afferent neurons revealed increased calcium influx induced by the 5-HT2A receptor agonist or capsaicin in cystitis rats, which could be inhibited by M100907. Moreover, RNA sequencing indicated that differentially expressed genes were enriched in inflammation-related pathways and cellular calcium homeostasis. These findings suggest that the 5-HT2A receptor is involved in the hypersensitivity of bladder afferent neurons in CYP-induced cystitis, and M100907 could alleviate bladder overactivity and hyperalgesia in CYP-induced cystitis by inhibiting neuronal hypersensitivity in the afferent pathways. The 5-HT2A receptor may be a potential therapeutic target for the treatment of IC/BPS.

Omega-3 Effects on Ligature-Induced Periodontitis in Rats with Fructose-Induced Metabolic Syndrome

Both periodontal disease (PD) and metabolic syndrome (MS) represent disorders of concern worldwide. Current evidence indicates that PD and MS might negatively influence each other, increasing the risk for cardiovascular diseases (CVD), via mutual inflammatory pathways. A failure of the inflammation resolution mechanisms is crucial for these comorbidities. Fish oil-derived omega-3 has been linked with resolution-driven responses in different pathological conditions during the last years. This study evaluated the impacts of omega-3 supplementation in a rat model combining ligature-induced PD and 10% fructose intake-elicited MS. Our main findings show that 10% fructose ingestion led to an elevation of Lee index and white adipose tissue (WAT) weight, along with hepatic alterations, accompanied by an increase of leptin, and a decrement of adiponectin serum amounts, regardless of PD induction. Noteworthy, the co-induction of PD and MS resulted in higher levels of glycemia and triglycerides, being this latter effect lessened by omega-3 supplementation. In this case, the beneficial effects of omega-3 might be associated with its ability to recover the decline of serum adiponectin levels in rats with PD plus MS. As expected, PD induction led to alveolar bone loss, independent of MS induction. However, the supplementation with omega-3 restored alveolar bone in PD control animals, but not in the rats with PD combined with MS. Our study extends the knowledge about PD and MS as comorbidities, showing novel effects of omega-3 supplementation in this context.

Icariin attenuates cyclophosphamide-induced cystitis via down-regulation of NF-кB and up-regulation of Nrf-2/HO-1 signaling pathways in mice model

Cystitis is a chronic bladder pain associated with frequency and nocturia. In the present study, Icariin a prenylated flavonoid extracted from Epimedium koreanum, was investigated against cyclophosphamide (CYP)-induced cystitis pain in mice model. Preliminarily in an acute model, single dose of CYP (150 mg/kg; i.p) was administered followed by Icariin (5, 25 and 50 mg/kg, i.p.). The visceral sensitivity and nociceptive behaviors were significantly ameliorated by pretreatment with Icariin (25, 50 mg/kg) that were assessed by spontaneous pain scoring, von Frey test and clinical scoring. Further, in chronic model Icariin (25 mg/kg, i.p.) was administered for 10 consecutive days prior to CYP (75 mg/kg; i.p) challenged every 3rd day for the duration of 10 days. Icariin not only had a protective effect on edema including bladder wet weight and hemorrhage but also had a potential to reduce vascular permeability, mast cells infiltration and tissue fibrosis. Evidently, Icariin prevented the neutrophilia/lymphopenia caused by CYP, and markedly improved the antioxidant enzymes level including superoxide dismutase, glutathione sulfo-transferase, catalase, glutathione level and reduced Malondialdehyde level, myeloperoxidase activity and nitric oxide, and also decreased the production of tumor necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) in bladder. Icariin markedly enhanced the Nrf-2, heme oxygenase (HO-1) and IкB-α expression, while attenuated the expression level of Keap1, TLR-4, NF-кB, i-NOS, COX-2 and TRPV1 as compared to negative group. This research illustrated the anti-inflammatory properties of Icariin and effectively improved CYP-induced cystitis pain.

Preventive Supplementation of Omega-3 Reduces Pain and Pro-inflammatory Cytokines in a Mouse Model of Complex Regional Pain Syndrome Type I

Complex regional pain syndrome type I (CRPS-I) is a condition that responds poorly to treatments. The role of omega-3 fatty acids in the treatment of inflammatory disorders is well described in the literature; however, few studies have evaluated its therapeutic benefits in different types of pain. We evaluated the potential antihyperalgesic and anti-inflammatory effects of preventive omega-3 supplementation in an animal model of CRPS-I. In experiment 1, Swiss female mice were supplemented for 30 days with omega-3 before the induction of the CRPS-I model and 14 days after. Mechanical hyperalgesia was evaluated at baseline and from the 4th to the 14th day after CPRS-I induction along with open field locomotor activity after 30 days of supplementation. In experiment 2, Swiss female mice were supplemented for 30 days with omega-3 and then subjected to the CRPS-I model. Twenty-four hours later the animals were euthanized, and tissue samples of the spinal cord and right posterior paw muscle were taken to measure pro-inflammatory cytokine TNF and IL-1β concentrations. Omega-3 supplementation produced antihyperalgesic and anti-inflammatory effects, as well as reducing pro-inflammatory cytokine concentrations, without altering the animals’ locomotion. No open field locomotor changes were found. The 30-day supplementation at the tested dose was effective in the CRPS-I model.

Immunoregulatory Effect of Preventive Supplementation of Omega-3 Fatty Acid in a Complex Regional Pain Syndrome Type I Model in Mice

Objective

Complex regional pain syndrome (CRPS) is usually triggered by trauma or a surgical procedure, and it typically becomes an established one after an intense inflammatory process with chronic pain and edema as the main symptoms. Available treatments for CRPS have low efficacy. This study aimed to evaluate the clinical and immunoregulatory effects of omega-3 polyunsaturated fatty acid (PUFA) supplementation on paw edema and anti- and pro-inflammatory cytokines and macrophage phenotypes in the chronic post-ischemia pain (CPIP) preclinical model of CRPS-Type I.

Methods

Female Swiss mice were supplemented with omega-3, corn oil, or saline and then submitted to the CPIP model of ischemia/reperfusion (I/R) injury. Supplementation was carried out for 30 days prior to and up to 2 or 15 days after the induction of CPIP, according to experimental protocols. The supplementation protocol included 1,500 mg/kg of omega-3 or corn oil through an intragastric route (gavage). Paw edema, interleukin- (IL-) 4, IL-10, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor (TNF) were then measured in the paw skin and muscle by enzyme-linked immunosorbent assay (ELISA), and macrophage phenotypes (M1 and M2) assessed in the paw muscle by Western blotting.

Results

The CPIP model induced an increase in paw thickness up to 72 h post-I/R. Mice supplemented with omega-3 compared to the saline group displayed reduced edema but neither altered skin IL-4 or skin and muscle TGF-β1, TNF, and MCP-1 concentrations, nor did they exhibit significantly altered muscle macrophage phenotype on the 2nd-day post-CPIP. However, omega-3 supplementation reversed the I/R-related reduction in IL-4 in the paw muscle compared to groups supplemented with saline and corn oil. Furthermore, omega-3 promoted the reduction of IL-10 levels in the paw skin, compared to animals with lesions supplemented with saline, until the 2nd-day post-CPIP. On the 15th day post-CPIP, IL-10 was significantly increased in the muscle of animals supplemented with omega-3 compared to the saline group.

Conclusion

The results suggest that omega-3 PUFA supplementation has anti-inflammatory effects in the CPIP model of CRPS-Type I, significantly reducing paw edema and regulating concentrations of anti-inflammatory cytokines, including IL-4 and IL-10.

Understanding the appetite modulation pathways: The role of the FFA1 and FFA4 receptors

Pharmaconutrition is an area of current interest, especially concerning the advances in the pharmacology of nutrient-sensing receptors, as have been accomplished in the last 20 years. The family of free fatty acid (FFA) receptors is composed of four members, sequentially named as FFA1 to FFA4, which are activated by the short to long-chain fatty acids. The affinity of the FFA1 and FFA4 receptors for the omega-3 polyunsaturated fatty acids prompted pre-clinical and clinical investigations regarding their involvement in metabolic diseases. The main studies have been focused on the receptors' expression analyses, the featuring of knockout mice, and the assessment of selective synthetic ligands. These clearly have indicated a relevant role for FFA1 and FFA4 in the peripheral and central circuits for the regulation of energetic metabolism. This review article aimed to discuss the relevance of the FFA1 and FFA4 receptors in appetite-related complications, mainly related to obesity, cancer cachexia, and anorexia in the elderly, emphasizing whether their pharmacological modulation might be useful for the management of these disorders.

Suppression of adenosine A2a receptors alleviates bladder overactivity and hyperalgesia in cyclophosphamide-induced cystitis by inhibiting TRPV1

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a type of chronic bladder inflammation characterized by increased voiding frequency, urgency and pelvic pain. The sensitization of bladder afferents is widely regarded as one of the pathophysiological changes in the development of IC/BPS. There is evidence that adenosine A_2a receptors are involved in regulating the sensitization of sensory afferents. However, the effect of adenosine A_2a receptors on cystitis remains unknown. In the present study, a rat model of chronic cystitis was established by intraperitoneal injection with cyclophosphamide (CYP). Cystometry and behavioral tests were performed to investigate bladder micturition function and nociceptive pain. The rats with chronic cystitis showed symptoms of bladder overactivity, characterized by an increase in bladder voiding frequency and voiding pressure. CYP treatment significantly increased the expression of the A_2a receptor in bladder afferent fibers and dorsal root ganglion (DRG) neurons. The A_2a receptor antagonist ZM241385 prevented bladder overactivity and hyperalgesia elicited by CYP-induced cystitis. In addition, the A_2a receptor and TRPV1 were coexpressed on DRG neurons. The TRPV1 antagonist capsazepine blocked bladder overactivity induced by the A_2a receptor agonist CGS21680. In contrast, ZM241385 significantly inhibited the capsaicin-induced increase in intracellular calcium concentration in DRG neurons. These results suggest that suppression of adenosine A_2a receptors in bladder afferents alleviates bladder overactivity and hyperalgesia elicited by CYP-induced cystitis in rats by inhibiting TRPV1, indicating that the adenosine A_2a receptor in bladder afferents is a potential therapeutic target for the treatment of IC/BPS.

Targeting FFA1 and FFA4 receptors in cancer-induced cachexia

Free fatty acid (FFA) receptors FFA1 and FFA4 are omega-3 molecular targets in metabolic diseases; however, their function in cancer cachexia remains unraveled. We assessed the role of FFA1 and FFA4 receptors in the mouse model of cachexia induced by Lewis lung carcinoma (LLC) cell implantation. Naturally occurring ligands such as α-linolenic acid (ALA) and docosahexaenoic acid (DHA), the synthetic FFA1/FFA4 agonists GW9508 and TUG891, or the selective FFA1 GW1100 or FFA4 AH7614 antagonists were tested. FFA1 and FFA4 expression and other cachexia-related parameters were evaluated. GW9508 and TUG891 decreased tumor weight in LLC-bearing mice. Regarding cachexia-related end points, ALA, DHA, and the preferential FFA1 agonist GW9508 rescued body weight loss. Skeletal muscle mass was reestablished by ALA treatment, but this was not reflected in the fiber cross-sectional areas (CSA) measurement. Otherwise, TUG891, GW1100, or AH7614 reduced the muscle fiber CSA. Treatments with ALA, GW9508, GW1100, or AH7614 restored white adipose tissue (WAT) depletion. As for inflammatory outcomes, ALA improved anemia, whereas GW9508 reduced splenomegaly. Concerning behavioral impairments, ALA and GW9508 rescued locomotor activity, whereas ALA improved motor coordination. Additionally, DHA improved grip strength. Notably, GW9508 restored abnormal brain glucose metabolism in different brain regions. The GW9508 treatment increased leptin levels, without altering uncoupling protein-1 downregulation in visceral fat. LLC-cachectic mice displayed FFA1 upregulation in subcutaneous fat, but not in visceral fat or gastrocnemius muscle, whereas FFA4 was unaltered. Overall, the present study shed new light on FFA1 and FFA4 receptors' role in metabolic disorders, indicating FFA1 receptor agonism as a promising strategy in mitigating cancer cachexia.

Nociceptin/orphanin FQ receptor modulates painful and fatigue symptoms in a mouse model of fibromyalgia

Generalized pain and fatigue are both hallmarks of fibromyalgia, a syndrome with an indefinite etiology. The treatment options for fibromyalgia are currently limited, probably because of its intricate pathophysiology. Thus, further basic and clinical research on this condition is currently needed. This study investigated the effects of nociceptin/orphanin FQ (N/OFQ) receptor (NOPr) ligands and the modulation of the NOP system in the preclinical mouse model of reserpine-induced fibromyalgia. The effects of administration of the natural agonist N/OFQ and the selective NOPr antagonists (UFP-101 and SB-612111) were evaluated in fibromyalgia-related symptoms in reserpine-treated mice. The expression of prepronociceptin/orphanin FQ and NOPr was assessed in central and peripheral sites at different time points after reserpine administration. Nociceptin/orphanin FQ displayed dual effects in the behavioral changes in the reserpine-elicited fibromyalgia model. The peptide NOPr antagonist UFP-101 produced analgesic and antifatigue effects, by preventing alterations in brain activity and skeletal muscle metabolism, secondary to fibromyalgia induction. The nonpeptide NOPr antagonist SB-612111 mirrored the favorable effects of UFP-101 in painful and fatigue alterations induced by reserpine. A time-related up- or downregulation of prepronociceptin/orphanin FQ and NOPr was observed in supraspinal, spinal, and peripheral sites of reserpine-treated mice. Our data shed new lights on the mechanisms underlying the fibromyalgia pathogenesis, supporting a role for N/OFQ-NOP receptor system in this syndrome.

Protective Effects of Omega-3 Fatty Acids in Cancer-Related Complications

Omega-3 polyunsaturated fatty acids (PUFAs) are considered immunonutrients and are commonly used in the nutritional therapy of cancer patients due to their ample biological effects. Omega-3 PUFAs play essential roles in cell signaling and in the cell structure and fluidity of membranes. They participate in the resolution of inflammation and have anti-inflammatory and antinociceptive effects. Additionally, they can act as agonists of G protein-coupled receptors, namely, GPR40/FFA1 and GPR120/FFA4. Cancer patients undergo complications, such as anorexia-cachexia syndrome, pain, depression, and paraneoplastic syndromes. Interestingly, the 2017 European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines for cancer patients only discuss the use of omega-3 PUFAs for cancer-cachexia treatment, leaving aside other cancer-related complications that could potentially be managed by omega-3 PUFA supplementation. This critical review aimed to discuss the effects and the possible underlying mechanisms of omega-3 PUFA supplementation in cancer-related complications. Data compilation in this critical review indicates that further investigation is still required to assess the factual benefits of omega-3 PUFA supplementation in cancer-associated illnesses. Nevertheless, preclinical evidence reveals that omega-3 PUFAs and their metabolites might modulate pivotal pathways underlying complications secondary to cancer, indicating that this is a promising field of knowledge to be explored.

Activation of GPR40 produces mechanical antiallodynia via the spinal glial interleukin-10/β-endorphin pathway

Background

The G protein-coupled receptor 40 (GPR40), broadly expressed in various tissues such as the spinal cord, exerts multiple physiological functions including pain regulation. This study aimed to elucidate the mechanisms underlying GPR40 activation-induced antinociception in neuropathic pain, particularly related to the spinal glial expression of IL-10 and subsequent β-endorphin.

Methods

Spinal nerve ligation-induced neuropathic pain model was used in this study. β-Endorphin and IL-10 levels were measured in the spinal cord and cultured primary microglia, astrocytes, and neurons. Double immunofluorescence staining of β-endorphin with glial and neuronal cellular biomarkers was also detected in the spinal cord and cultured primary microglia, astrocytes, and neurons.

Results

GPR40 was expressed on microglia, astrocytes, and neurons in the spinal cords and upregulated by spinal nerve ligation. Intrathecal injection of the GPR40 agonist GW9508 dose-dependently attenuated mechanical allodynia and thermal hyperalgesia in neuropathic rats, with E_max values of 80% and 100% MPE and ED₅₀ values of 6.7 and 5.4 μg, respectively. Its mechanical antiallodynia was blocked by the selective GPR40 antagonist GW1100 but not GPR120 antagonist AH7614. Intrathecal GW9508 significantly enhanced IL-10 and β-endorphin immunostaining in spinal microglia and astrocytes but not in neurons. GW9508 also markedly stimulated gene and protein expression of IL-10 and β-endorphin in cultured primary spinal microglia and astrocytes but not in neurons, originated from 1-day-old neonatal rats. The IL-10 antibody inhibited GW9508-stimulated gene expression of the β-endorphin precursor proopiomelanocortin (POMC) but not IL-10, whereas the β-endorphin antibody did not affect GW9508-stimulated IL-10 or POMC gene expression. GW9508 increased phosphorylation of mitogen-activated protein kinases (MAPKs) including p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), and its stimulatory effects on IL-10 and POMC expression were blocked by each MAPK isoform inhibitor. Spinal GW9508-induced mechanical antiallodynia was completely blocked by intrathecal minocycline, IL-10 neutralizing antibody, β-endorphin antiserum, and μ-opioid receptor-preferred antagonist naloxone.

Conclusions

Our results illustrate that GPR40 activation produces antinociception via the spinal glial IL-10/β-endorphin antinociceptive pathway.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1457-9) contains supplementary material, which is available to authorized users.

The role of kinin B1 and B2 receptors in the mouse model of oxazolone-induced atopic dermatitis

This study evaluated the role of kinin B₁ and B₂ receptors in the pre-clinical mouse model of oxazolone-induced atopic dermatitis. The B₁ R715 or B₂ HOE140 receptor antagonists were dosed at different schemes of treatment. After assessment of clinical lesion scores and pruritus, lesional skin samples were collected for histopathological analysis. The plasma extravasation and the expression of the metalloproteinase ADAMTS5 were also assessed. The immunopositivity for kinin receptors was evaluated in the skin, dorsal root ganglion (DRG), thoracic spinal cord and brain cortex sections. Marked upregulation of B₁ and B₂ receptors was observed in the skin of oxazolone-treated mice. The induction of atopic dermatitis led to a downregulation of both receptors in the DRG, without any alteration in the spinal cord and brain cortex. The repeated administration of HOE140 (50 nmol/kg; i.p.) partially inhibited the oxazolone-related pruritus, associated with a reduction of ADAMTS5 immunolabelling in the skin. Alternatively, R715 (438 nmol/kg; i.p.) produced a mild inhibition of plasma extravasation in oxazolone-challenged mice. Noteworthy, the repeated i.d. injection of R715 (30 nmol/site) or HOE140 (3 nmol/site) significantly reduced the histiocyte numbers, according to the histopathological analysis. Either B₁ or B₂ kinin antagonists, irrespective of the protocol of treatment, did not alter any other evaluated clinical or histological parameters. Data brings novel evidence about the role of kinin receptors in allergy-related conditions, such as atopic dermatitis. Further studies to test different protocols of treatment with kinin antagonists on in-depth cellular alterations underlying oxazolone-induced atopic dermatitis remain to be performed.

IPSE, a urogenital parasite-derived immunomodulatory protein, ameliorates ifosfamide-induced hemorrhagic cystitis through downregulation of pro-inflammatory pathways

Ifosfamide and other oxazaphosphorines can result in hemorrhagic cystitis, a constellation of complications caused by acrolein metabolites. We previously showed that a single dose of IPSE (Interleukin-4-inducing principle from Schistosoma eggs), a schistosome-derived host modulatory protein, can ameliorate ifosfamide-related cystitis; however, the mechanisms underlying this urotoxicity and its prevention are not fully understood. To provide insights into IPSE’s protective mechanism, we undertook transcriptional profiling of bladders from ifosfamide-treated mice, with or without pretreatment with IPSE or IPSE-NLS (a mutant of IPSE lacking nuclear localization sequence). Ifosfamide treatment upregulated a range of proinflammatory genes. The IL-1β-TNFα-IL-6 proinflammatory cascade via NFκB and STAT3 pathways was identified as the key driver of inflammation. The NRF2-mediated oxidative stress response pathway, which regulates heme homoeostasis and expression of antioxidant enzymes, was highly activated. Anti-inflammatory cascades, namely Wnt, Hedgehog and PPAR pathways, were downregulated. IPSE drove significant downregulation of major proinflammatory pathways including the IL-1β-TNFα-IL-6 pathways, interferon signaling, and reduction in oxidative stress. IPSE-NLS reduced inflammation but not oxidative stress. Taken together, we have identified signatures of acute-phase inflammation and oxidative stress in ifosfamide-injured bladder, which are reversed by pretreatment with IPSE. This work revealed several pathways that could be therapeutically targeted to prevent ifosfamide-induced hemorrhagic cystitis.

Activation of trigeminal ganglion satellite glial cells in CFA-induced tooth pulp pain in rats

This study further investigated the mechanisms underlying the rat model of tooth pulp inflammatory pain elicited by complete Freund's adjuvant (CFA), in comparison to other pulpitis models. Pulps of the left maxillary first molars were accessed. In the CFA group, the pulps were exposed, and CFA application was followed by dental sealing. In the open group, the pulps were left exposed to the oral cavity. For the closed group, the pulps were exposed, and the teeth were immediately sealed. Naïve rats were used as negative controls. Several parameters were evaluated at 1, 2, 3 and 8 days. There was no statistical significant difference among the groups when body weight variation, food or water consumption were compared. Analysis of serum cytokines (IL-1β, TNF or IL-6) or differential blood cell counts did not reveal any evidence of systemic inflammation. The CFA group displayed a significant reduction in the locomotor activity (at 1 and 3 days), associated with an increased activation of satellite glial cells in the ipsilateral trigeminal ganglion (TG; for up to 8 days). Amygdala astrocyte activation was unaffected in any experimental groups. We provide novel evidence indicating that CFA-induced pulp inflammation impaired the locomotor activity, with persistent activation of ipsilateral TG satellite cells surrounding sensory neurons, without any evidence of systemic inflammation or amygdala astrogliosis.

Food pyramid for subjects with chronic pain: foods and dietary constituents as anti-inflammatory and antioxidant agents

Emerging literature suggests that diet constituents may play a modulatory role in chronic pain (CP) through management of inflammation/oxidative stress, resulting in attenuation of pain. We performed a narrative review to evaluate the existing evidence regarding the optimum diet for the management of CP, and we built a food pyramid on this topic. The present review also describes the activities of various natural compounds contained in foods (i.e. phenolic compounds in extra-virgin olive oil (EVO)) listed on our pyramid, which have comparable effects to drug management therapy. This review included 172 eligible studies. The pyramid shows that carbohydrates with low glycaemic index should be consumed every day (three portions), together with fruits and vegetables (five portions), yogurt (125 ml), red wine (125 ml) and EVO; weekly: legumes and fish (four portions); white meat, eggs and fresh cheese (two portions); red or processed meats (once per week); sweets can be consumed occasionally. The food amounts are estimates based on nutritional and practical considerations. At the top of the pyramid there is a pennant: it means that CP subjects may need a specific customised supplementation (vitamin B12, vitamin D, n-3 fatty acids, fibre). The food pyramid proposal will serve to guide dietary intake with to the intent of alleviating pain in CP patients. Moreover, a targeted diet can also help to solve problems related to the drugs used to combat CP, i.e. constipation. However, this paper would be an early hypothetical proposal due to the limitations of the studies.

Beneficial Effects of the Calcium Channel Blocker CTK 01512-2 in a Mouse Model of Multiple Sclerosis

Voltage-gated calcium channels (VGCCs) play a critical role in neuroinflammatory diseases, such as multiple sclerosis (MS). CTK 01512-2 is a recombinant version of the peptide Phα1β derived from the spider Phoneutria nigriventer, which inhibits N-type VGCC/TRPA1-mediated calcium influx. We investigated the effects of this molecule in the mouse model of experimental autoimmune encephalomyelitis (EAE). The effects of CTK 01512-2 were compared to those displayed by ziconotide-a selective N-type VGCC blocker clinically used for chronic pain-and fingolimod-a drug employed for MS treatment. The intrathecal (i.t.) treatment with CTK 01512-2 displayed beneficial effects, by preventing nociception, body weight loss, splenomegaly, MS-like clinical and neurological scores, impaired motor coordination, and memory deficits, with an efficacy comparable to that observed for ziconotide and fingolimod. This molecule displayed a favorable profile on EAE-induced neuroinflammatory changes, including inflammatory infiltrate, demyelination, pro-inflammatory cytokine production, glial activation, and glucose metabolism in the brain and spinal cord. The recovery of spatial memory, besides a reduction of serum leptin levels, allied to central and peripheral elevation of the anti-inflammatory cytokine IL-10, was solely modulated by CTK 01512-2, dosed intrathecally. The intravenous (i.v.) administration of CTK 01512-2 also reduced the EAE-elicited MS-like symptoms, similarly to that seen in animals that received fingolimod orally. Ziconotide lacked any significant effect when dosed by i.v. route. Our results indicate that CTK 01512-2 greatly improved the neuroinflammatory responses in a mouse model of MS, with a higher efficacy when compared to ziconotide, pointing out this molecule as a promising adjuvant for MS management.

Dietary Chlorella vulgaris Ameliorates Altered Immunomodulatory Functions in Cyclophosphamide-Induced Immunosuppressive Mice

Based on the well-known toxicity of cyclophosphamide (CYP) on the immune system, this research investigated the modulating effects of the long-term dietary Chlorella vulgaris (CV) supplementation on the immunosuppression induced by CYP in mice, in order to provide a novel dietary design to mitigate the side effects of CYP therapy. Control, CYP-treated, CYP + CV (6%), CYP + CV (12%) and CYP + CV (24%) were used for 6 weeks, CV supplement in diet recovered the significantly reduced immunological function in CYP treated mice. As CV may have a modulating function through the inducible expression of cytokines, we assayed the expressions of interleukin-2 (IL-2), interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Our results suggested that CYP significantly reduced the lymphocytes proliferation and phagocytic activities of macrophages, and stimulated the production of IL-2, IL-12, TNF-α and IFN-γ and that this impairment has been successfully adjusted by CV supplementation. Treatment with the algae also enhanced the natural killer (NK) cells cytotoxicity, and ameliorate histological changes of the spleen in CYP-treated mice. Therefore, as we found in this study, a diet supplemented with whole CV has beneficial effects on CVP-induced immunosuppression, through its immunomodulatory potential.

Cyclophosphamide-induced HCN1 channel upregulation in interstitial Cajal-like cells leads to bladder hyperactivity in mice

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are confirmed to be expressed in bladder interstitial Cajal-like cells (ICC-LCs), but little is known about their possible role in cystitis-associated bladder dysfunction. The present study aimed to determine the functional role of HCN channels in regulating bladder function under inflammatory conditions. Sixty female wild-type C57BL/6J mice and sixty female HCN1-knockout mice were randomly assigned to experimental and control groups, respectively. Cyclophosphamide (CYP)-induced cystitis models were successfully established in these mice. CYP treatment significantly enhanced HCN channel protein expression and I_h density and significantly altered bladder HCN1 channel regulatory proteins. Carbachol (CCH) and forskolin (FSK) exerted significant effects on bladder ICC-LC [Ca²⁺]_i in CYP-treated wild-type (WT) mice, and HCN1 channel ablation significantly decreased the effects of CCH and FSK on bladder ICC-LC [Ca²⁺]_i in both naive and CYP-treated mice. CYP treatment significantly potentiated the spontaneous contractions and CCH (0.001–10 μM)-induced phasic contractions of detrusor strips, and HCN1 channel deletion significantly abated such effects. Finally, we demonstrated that the development of CYP-induced bladder overactivity was reversed in HCN1−/− mice. Taken together, our results suggest that CYP-induced enhancements of HCN1 channel expression and function in bladder ICC-LCs are essential for cystitis-associated bladder hyperactivity development, indicating that the HCN1 channel may be a novel therapeutic target for managing bladder hyperactivity.

Spinal astrocytic activation contributes to mechanical allodynia in a rat model of cyclophosphamide-induced cystitis

BACKGROUND

Previous studies have demonstrated that glial cells play an important role in the generation and maintenance of neuropathic pain. Activated glial cells produce numerous mediators such as proinflammatory cytokines that facilitate neuronal activity and synaptic plasticity. Similarly, bladder pain syndrome/interstitial cystitis shares many characteristics of neuropathic pain. However, related report on the involvement of spinal glia in bladder pain syndrome/interstitial cystitis-associated pathological pain and the underlying mechanisms are still lacking. The present study investigated spinal glial activation and underlying molecular mechanisms in a rat model of bladder pain syndrome/interstitial cystitis.

RESULTS

A rat model of bladder pain syndrome/interstitial cystitis was established via systemic injection with cyclophosphamide. Mechanical allodynia was tested with von Frey monofilaments and up-down method. Moreover, Western blots and double immunofluorescence were used to detect the expression and location of glial fibrillary acidic protein, OX42/Iba1, P-P38, NeuN, interleukin (IL)-1β, phosphorylation of N-methyl-D-aspartate receptor 1 (P-NR1), and IL-1 receptor I (IL-1RI) in the L6-S1 spinal cord. We found that glial fibrillary acidic protein rather than OX42/Iba1 or P-P38 was significantly increased in the spinal cord of cyclophosphamide-induced cystitis. L-alpha-aminoadipate but not minocycline markedly attenuated the allodynia. Furthermore, we found that spinal IL-1β was dramatically increased in cyclophosphamide-induced cystitis, and activated astrocytes were the only source of IL-1β release, which contributed to allodynia in cystitis rats. Besides, spinal P-NR1 was statistically increased in cyclophosphamide-induced cystitis and only localized in IL-1RI positive neurons in spinal dorsal horn. Additionally, NR antagonist significantly attenuated the cystitis-induced pain. Interestingly, the time course of the P-NR1 expression paralleled to that of IL-1β or glial fibrillary acidic protein.

CONCLUSIONS

Our results demonstrated that astrocytic activation but not microglial activation contributed to the allodynia in cyclophosphamide-induced cystitis and IL-1β released from astrocytes might bind to its endogenous receptor on the neurons inducing the phosphorylation of NR1 subunit, leading to sensory neuronal hyperexcitability and pathological pain.