Effects of the compounds MV8608 and MV8612 obtained from Mandevilla velutina in the model of hemorrhagic cystitis induced by cyclophosphamide in rats

Protective effects of hydrogen sulfide pretreatment on cyclophosphamide-induced bladder dysfunction in rats via suppression of bladder afferent nerves

Cyclophosphamide (CYP), a broad-spectrum anticancer drug, causes serious side effects, such as haemorrhagic cystitis (HC). Hydrogen sulfide (H₂S), an endogenous gasotransmitter, has physiological properties, including anti-inflammation, anti-oxidation, and neuromodulation. In this study, we investigated the effects of NaHS (H₂S donor) pretreatment on bladder dysfunction in CYP-treated rats. Male Wistar rats were intraperitoneally pretreated with NaHS (3 or 10 μmol/kg) or vehicle once daily for 7 days before cystometry, and CYP (150 mg/kg) or saline was intraperitoneally administered 2 days before cystometry. After cystometry, the bladder tissues were collected for haematoxylin and eosin staining. In some rats, capsaicin (CAP), which can desensitise CAP-sensitive afferent nerves, was subcutaneously injected at 125 mg/kg 4 days before cystometry. CYP reduced intercontraction intervals (ICI) and bladder compliance (Comp) and increased the number of non-voiding contractions (NVCs) compared with the saline-treated control group. NaHS pretreatment dose-dependently improved the CYP-induced these changes. In bladder tissues, CYP increased histological scores of neutrophil infiltration, haemorrhage, and oedema, while NaHS had no effect on these CYP-induced changes. CAP showed a tendency to suppress CYP-induced changes in ICI. NaHS-induced improvement in CYP-induced changes in urodynamic parameters were not detected in CAP-treated rats. These findings suggest that NaHS pretreatment prevented bladder dysfunction in CYP-treated rats by suppressing CAP-sensitive bladder afferent nerves, but not by suppressing bladder inflammation. Therefore, H₂S represents a new candidate as a protective drug for bladder dysfunction induced by HC, a side effect of CYP chemotherapy.

5-Aminolevulinic acid has the potential to prevent bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis

OBJECTIVES

To investigate the effects of pretreatment with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate on bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis in rats.

METHODS

Male Wistar rats (340-460 g) were pretreated with vehicle or with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate (100/157 or 300/471 mg/kg/day, po) once daily for 7 days before cystometry. Saline or cyclophosphamide (150 mg/kg, ip) was administered 2 days before cystometry. Cystometry was performed under urethane anesthesia (0.8 g/kg, ip) via a catheter inserted into the bladder. After cystometry, bladder tissues were collected to perform hematoxylin and eosin staining for pathological evaluation (neutrophil infiltration, edema, and bleeding scores), and for enzyme-linked immunosorbent assay and real-time polymerase chain reaction for investigating tissue levels of myeloperoxidase, and mRNA levels of haem oxygenase-1 as a cytoprotective molecule.

RESULTS

Compared to controls, cyclophosphamide induced a shorter intercontraction interval, lower bladder compliance, increased number of non-voiding contractions, and increased pathological scores and myeloperoxidase expression in the bladder. Pretreatment with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate (300/471 mg/kg/day) significantly improved cyclophosphamide-induced intercontraction interval shortening and increases in number of non-voiding contractions and neutrophil infiltration/bleeding scores and enhanced haem oxygenase-1 expression in the bladder. In addition, cyclophosphamide-induced decreases in bladder compliance and increases in myeloperoxidase were not detected with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate pretreatment.

CONCLUSIONS

Pretreatment with 5-aminolevulinic acid expects protective effects on bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis by improving inflammatory changes in bladder tissues perhaps via up-regulation of haem oxygenase-1.

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.

Repeated Low-Dose Acrolein Triggers Irreversible Lamina Propria Edema in Urinary Bladder, Transient Voiding Behavior and Widening of Eyes to Mechanical Stimuli

Acrolein is a metabolite of cyclophosphamide (CYP), an alkylating agent used for a wide range of benign and malignant diseases. CYP treatments are known to trigger hemorrhagic cystitis in patients and animals. Significant effort has been made to prevent CYP/acrolein-induced cystitis, while still maintaining its therapeutic benefits. As a result, supplementary therapeutic options to mediate the protective role against CYP/acrolein and lower doses of CYP are currently given to targeted patients, as compared to past treatments. There is still a need to further study the effects of the repeated low-dose CYP/acrolein on the pathophysiology of the urinary bladder. In our study, a one-time treatment of acrolein and repeated low-dose acrolein triggered the thickening of the smooth muscle and lamina propria in the urinary bladder of C57BL/6J mice, respectively. The first dose of acrolein did not trigger voiding dysfunction, but the second dose triggered high-volume low-frequency voiding. Interestingly, our new scoring criteria and concurrent behavioral assessment revealed that mice with repeated low-dose acrolein had a wider opening of eyes in response to mechanical stimuli. Our study suggests that clinical symptoms among patients undergoing prolonged low-dose CYP may differ from previously reported symptoms of CYP-induced hemorrhagic cystitis.

Double benefit of metformin treatment: improved bladder function in cyclophosphamide-induced cystitis and enhanced cytotoxicity in cancer cells

Cyclophosphamide (CP) is a widely used anti-neoplastic drug; however, it leads to bladder dysfunction in the form of hemorrhagic cystitis that is a serious dose-limiting complication in cancer patients. We aimed to evaluate the protective effects of metformin (MET) in a mouse model of CP-related cystitis in parallel with its effect on CP-induced cytotoxicity in a breast cancer cell line, MDA-MB-231. Cystitis was induced by a single intraperitoneal injection of CP (300 mg/kg), and mice were administered MET, mesna, or vehicle treatment. 24 hours after cystitis induction, the bladders were removed for histopathological analysis and ex vivo evaluation of detrusor muscle contractility. The effect of MET on the cytotoxicity of CP in MDA-MB-231 cells was evaluated as the viability of the cells via MTT assay. Histopathological evaluation confirmed that CP induced a severe cystitis, and MET partially inhibited CP-induced bladder damage. Carbachol-evoked cholinergic contractions were significantly decreased in detrusor strips of mice injected with CP only compared to control (E_max=293.67± 20.00 vs. 497.79± 21.78 mg tension/mg tissue, respectively). In CP-injected mice, treatment with 100 mg/kg MET restored cholinergic contractions (E_max=473.72±62.61 mg tension/mg tissue). In MDA-MB-231 cells, MET decreased their viability, and the combination of MET and CP caused more decrease in cell viability as compared to CP alone (p<0.05), demonstrating that MET enhances the cytotoxicity of CP in these cancer cells. Our results indicate that MET has a strong potential as a therapeutic adjuvant to prevent CP-induced cystitis while enhancing the efficacy of CP.

Urinary bladder sigma-1 receptors: A new target for cystitis treatment

No adequate treatment is available for painful urinary bladder disorders such as interstitial cystitis/bladder pain syndrome, and the identification of new urological therapeutic targets is an unmet need. The sigma-1 receptor (σ1-R) modulates somatic pain, but its role in painful urological disorders is unexplored. The urothelium expresses many receptors typical of primary sensory neurons (e.g. TRPV1, TRPA1 and P2X3) and high levels of σ1-R have been found in these neurons; we therefore hypothesized that σ1-R may also be expressed in the urothelium and may have functional relevance in this tissue. With western blotting and immunohistochemical methods, we detected σ1-R in the urinary bladder in wild-type (WT) but not in σ1-R-knockout (σ1-KO) mice. Interestingly, σ1-R was located in the bladder urothelium not only in mouse, but also in human bladder sections. The severity of histopathological (edema, hemorrhage and urothelial desquamation) and biochemical alterations (enhanced myeloperoxidase activity and phosphorylation of extracellular regulated kinases 1/2 [pERK1/2]) that characterize cyclophosphamide-induced cystitis was lower in σ1-KO than in WT mice. Moreover, cyclophosphamide-induced pain behaviors and referred mechanical hyperalgesia were dose-dependently reduced by σ1-R antagonists (BD-1063, NE-100 and S1RA) in WT but not in σ1-KO mice. In contrast, the analgesic effect of morphine was greater in σ1-KO than in WT mice. Together these findings suggest that σ1-R plays a functional role in the mechanisms underlying cyclophosphamide-induced cystitis, and modulates morphine analgesia against urological pain. Therefore, σ1-R may represent a new drug target for urinary bladder disorders.

The Quinovic Acid Glycosides Purified Fraction from Uncaria tomentosa Protects against Hemorrhagic Cystitis Induced by Cyclophosphamide in Mice

Uncaria tomentosa is widely used in folk medicine for the treatment of numerous diseases, such as urinary tract disease. Hemorrhagic cystitis (HE) is an inflammatory condition of the bladder associated with the use of anticancer drugs such as cyclophosphamide (CYP). Sodium 2-mercaptoethanesulfonate (Mesna) has been used to prevent the occurrence of HE, although this compound is not effective in established lesions. It has been demonstrated that the purinergic system is involved in several pathophysiological events. Among purinergic receptors, P2X7 deserves attention because it is involved in HE induced by CYP and, therefore, can be considered a therapeutic target. The objective of this study was to investigate the potential therapeutic effect of the quinovic acid glycosides purified fraction (QAPF) from U. tomentosa in the mouse model of CYP-induced HE. Pretreatment with QAPF not only had a protective effect on HE-induced urothelial damage (edema, hemorrhage and bladder wet weight) but was also able to control visceral pain, decrease IL-1β levels and down-regulates P2X7 receptors, most likely by inhibit the neutrophils migration to the bladder. This research clearly demonstrates the promising anti-inflammatory properties of QAPF, supporting its use as complementary therapy. QAPF represents a promising therapeutic option for this pathological condition.

Pharmacological inhibition of CXCR2 chemokine receptors modulates paraquat-induced intoxication in rats

Paraquat (PQ) is an agrochemical agent commonly used worldwide, which is allied to potential risks of intoxication. This herbicide induces the formation of reactive oxygen species (ROS) that ends up compromising various organs, particularly the lungs and the brain. This study evaluated the deleterious effects of paraquat on the central nervous system (CNS) and peripherally, with special attempts to assess the putative protective effects of the selective CXCR2 receptor antagonist SB225002 on these parameters. PQ-toxicity was induced in male Wistar rats, in a total dose of 50 mg/kg, and control animals received saline solution at the same schedule of administration. Separate groups of animals were treated with the selective CXCR2 antagonist SB225002 (1 or 3 mg/kg), administered 30 min before each paraquat injection. The major changes found in paraquat-treated animals were: decreased body weight and hypothermia, nociception behavior, impairment of locomotor and gait capabilities, enhanced TNF-α and IL-1β expression in the striatum, and cell migration to the lungs and blood. Some of these parameters were reversed when the antagonist SB225002 was administered, including recovery of physiological parameters, decreased nociception, improvement of gait abnormalities, modulation of striatal TNF-α and IL-1β expression, and decrease of neutrophil migration to the lungs and blood. Taken together, our results demonstrate that damage to the central and peripheral systems elicited by paraquat can be prevented by the pharmacological inhibition of CXCR2 chemokine receptors. The experimental evidence presented herein extends the comprehension on the toxicodynamic aspects of paraquat, and opens new avenues to treat intoxication induced by this herbicide.

Role of CXCR2 and TRPV1 in functional, inflammatory and behavioural changes in the rat model of cyclophosphamide-induced haemorrhagic cystitis

BACKGROUND AND PURPOSE

Cyclophosphamide induces urotoxicity characterized by the development of cystitis, which involves bladder overactivity and inflammation. Here, we investigated the roles of chemokine receptor 2 (CXCR2) and transient receptor potential vanilloid 1 (TRPV1) channels in a rat model of cyclophosphamide-induced cystitis.

EXPERIMENTAL APPROACH

Cystitis induced by cyclophosphamide in rats was assessed by gross morphology, histology and immunohistochemistry of bladder tissue. mRNA for CXCR2 and TRPV1 channels were measured by RT-PCR. Nociceptive responses in paw and abdomen, along with cystometric measures were recorded.

KEY RESULTS

Cyclophosphamide, i.p., induced pain behaviour, bladder inflammation and voiding dysfunction. The CXCR2 antagonist, SB225002, the TRPV1 channel antagonist, SB366791 or their combination reduced the mechanical hypersensitivity of paw and abdominal area and nociceptive behaviour after cyclophosphamide. Cyclophosphamide-induced cystitis was characterized by haemorrhage, oedema, neutrophil infiltration and other inflammatory changes, which were markedly decreased by the antagonists. Up-regulation of CXCR2 and TRPV1 mRNA in the bladder after cyclophosphamide was inhibited by SB225002, SB366791 or their combination. Expression of CXCR2 and TRPV1 channels was increased in the urothelium after cyclophosphamide. Bladder dysfunction was shown by increased number of non-voiding contractions (NVCs) and bladder pressures and a reduction in bladder capacity (BC), voided volume (VV) and voiding efficiency (VE). SB225002 or its combination with SB366791 reduced bladder pressures, whereas SB225002, SB366791 or their combination increased BC, VV and VE, and also reduced the number of NVCs.

CONCLUSIONS AND IMPLICATIONS

CXCR2 and TRPV1 channels play important roles in cyclophosphamide-induced cystitis in rats and could provide potential therapeutic targets for cystitis.

The role of P2X7 purinergic receptors in inflammatory and nociceptive changes accompanying cyclophosphamide-induced haemorrhagic cystitis in mice

BACKGROUND AND PURPOSE

ATP is released in response to cellular damage, and P2X7 receptors have an essential role in the onset and maintenance of pathological changes. Haemorrhagic cystitis (HC) is a well-known adverse effect of therapy with cyclophosphamide used for the treatment of many solid tumours and autoimmune conditions. Here we have evaluated the role of P2X7 receptors in a model of HC induced by cyclophosphamide.

EXPERIMENTAL APPROACH

Effects of pharmacological antagonism or genetic deletion of P2X7 receptor on cyclophosphamide-induced HC in mice was assessed by nociceptive and inflammatory measures. In addition, the presence of immunoreactive P2X7 receptors was assessed by immunohistochemistry.

KEY RESULTS

Pretreatment with the selective P2X7 receptor antagonist A-438079 or genetic ablation of P2X7 receptors reduced nociceptive behaviour scores in the HC model. The same strategies decreased both oedema and haemorrhage indices, on macroscopic or histological evaluation. Treatment with A-438079 decreased the staining for c-Fos in the lumbar spinal cord and brain cortical areas. Treatment with A-438079 also prevented the increase of urinary bladder myeloperoxidase activity and macrophage migration induced by cyclophosphamide and reduced the tissue levels of IL-1β and TNF-α. Finally, P2X7 receptors were markedly up-regulated in the bladders of mice with cyclophosphamide-induced HC.

CONCLUSIONS AND IMPLICATIONS

P2X7 receptors were significantly involved in a model of HC induced by cyclophosphamide. Pharmacological inhibition of these receptors might represent a new therapeutic option for this pathological condition.