Cyclophosphamide Induced Cystitis: Role of Nitric Oxide Synthase, Cyclooxygenase-1 and 2, and NK1Receptors

Uro-protective role of chrysin against cyclophosphamide-induced hemorrhagic cystitis in rats involving the turning-off NF-κB/P38-MAPK, NO/PARP-1 and STAT-3 signaling cascades

BACKGROUND

Chemotherapeutic agents are used to treat a wide range of cancer types, but they cause serious side effects which must be managed after treatment. Cyclophosphamide (CYP) is one of chemotherapeutic drugs that causes hemorrhagic cystitis (HC) induced by acrolein.

OBJECTIVE

The current investigation intended to uncover the role of chrysin (CHR) in CYP-induced HC in rats and explore the signaling pathway beyond this effect.

ANALYSIS

process: A single dose of CYP (200 mg/kg/IP) was injected, meanwhile CHR (25, 50 and 100 mg/kg, P.O) was administered respectively for 7 days prior to CYP administration and resume for 7 days afterwards. Urinary bladder tissue was then isolated from all rats to assess oxidative stress and inflammatory biomarkers. Moreover, histopathological examinations were performed.

RESULTS

Treatment with CHR showed a marked alleviation in oxidative stress biomarkers induced by CYP. Furthermore, CHR treatment presented a dose-dependent boost in the anti-inflammatory; IL-10 levels and a drop in the pro-inflammatory biomarkers; IL-1β, IL-6, and TNF-α. Additionally, stabilization of the PARP-1 protein expression was also detected thus preventing DNA damage. Similarly, CHR restored the urinary bladder cGMP levels. Notably, CHR treatment was accompanied with inhibition in NF-κB/p38-MAPK, NO/PARP-1 and STAT-3 signaling pathways inflammatory cascades. All these findings conformed with the histopathological examinations as well as iNOS immunostaining in the urinary bladder tissue.

CONCLUSION

Co-administration of CHR and CYP attained uro-protective therapeutic potential to guard against HC as well as spot the tangled mechanism of CHR in attenuating the HC induced by CYP.

Absence of prostacyclin greatly relieves cyclophosphamide-induced cystitis and bladder pain in mice

Cyclophosphamide (CP) has been widely used in the treatment of various malignancies and autoimmune diseases, but acrolein, a byproduct of CP, causes severe hemorrhagic cystitis as the major side effect of CP. On the other hand, a large amount of prostacyclin (PGI₂ ) is produced in bladder tissues, and PGI₂ has been shown to play a critical role in bladder homeostasis. PGI₂ is biosynthesized from prostaglandin (PG) H₂ , the common precursor of PGs, by PGI₂ synthase (PTGIS) and is known to also be involved in inflammatory responses. However, little is known about the roles of PTGIS-derived PGI₂ in bladder inflammation including CP-induced hemorrhagic cystitis. Using both genetic and pharmacological approaches, we here revealed that PTGIS-derived PGI₂ -IP (PGI₂ receptor) signaling exacerbated CP-induced bladder inflammatory reactions. Ptgis deficiency attenuated CP-induced vascular permeability and chemokine-mediated neutrophil migration into bladder tissues and then suppressed hemorrhagic cystitis. Treatment with RO1138452, an IP selective antagonist, also suppressed CP-induced cystitis. We further found that cystitis-related nociceptive behavior was also relieved in both Ptgis^-/- mice and RO1138452-treated mice. Our findings may provide new drug targets for bladder inflammation and inflammatory pain in CP-induced hemorrhagic cystitis.

Edaravone mitigates hemorrhagic cystitis by modulating Nrf2, TLR-4/NF-κB, and JAK1/STAT3 signaling in cyclophosphamide-intoxicated rats

Hemorrhagic cystitis is a potentially deadly complication associated with radiation therapy and chemotherapy. This study explored the protective effect of edaravone (ED) on cyclophosphamide (CP)-induced hemorrhagic cystitis, oxidative stress, and inflammation in rats. The animals received 20 mg/kg ED for 10 days and a single injection of 200 mg/kg CP on day 7. CP induced tissue injury manifested by the diffuse necrotic changes, disorganization of lining mucosa, focal hemorrhagic patches, mucosal/submucosal inflammatory cells infiltrates, and edema. CP increased malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-alpha, and interleukin 6 (IL-6), decreased IL-10, and upregulated toll-like receptor 4 (TLR-4), nuclear factor-kappa B (NF-κB) p65, Janus kinase 1 (JAK1), and signal transducer and activator of transcription 3 (STAT3) in the urinary bladder of rats. ED effectively prevented the histopathological alterations, decreased MDA, NO, and inflammatory mediators, and downregulated TLR-4, NF-κB, JAK1, and STAT3 in CP-induced rats. Treatment with ED upregulated ikβ kinase β, IL-10, nuclear factor-erythroid 2 related factor 2 (Nrf2), and cytoglobin, and boosted glutathione, superoxide dismutase, and glutathione S-transferase. Molecular docking simulations revealed the ability of ED to bind TLR-4, NF-κB, JAK1, and STAT3. In vitro, ED increased the cytotoxic activity of CP against HeLa, Caco-2, and K562 cell lines. In conclusion, ED prevented CP-induced hemorrhagic cystitis in rats by attenuating oxidative stress, suppressing TLR-4/NF-κB, and JAK1/STAT3 signaling and boosted Nrf2, cytoglobin, and antioxidants.

Immunohistochemical and histological evaluations of cyclophosphamide-induced acute cardiotoxicity in wistar rats: The role of turmeric extract (curcuma)

Chemotherapy-induced cardiac derangement is a major concern in health sector. Cyclophosphamide as a chemotherapeutic agent induces acute cardiotoxicity through its toxic metabolite, acrolein. This study evaluated the effect of ethanol extract of turmeric on cyclophosphamide-induced acute cardiotoxicity in Wistar rats. Thirty-five healthy Wistar rats, weighing 200-250g were randomly assigned into 7 groups (Groups A, B, C, D, E, F and G) N=5. Group A was the control, group B was negative control, and group C was administered 200mg/kg of turmeric extract (orally) only. While groups B, D, E, F and G were all administered 100mg/kg cyclophosphamide (i.p) for 10 days. Groups D and E were administered 100mg/kg and 200mg/kg of turmeric extract (orally) respectively for 72 hours before cyclophosphamide administration. Groups F and G were concomitantly administered 100mg/kg cyclophosphamide (i.p) with doses of 100mg/kg and 200mg/kg of turmeric extract (orally) respectively. The rats were sacrificed under ketamine anesthesia (30mg/kg i.m). The left ventricle of the heart was excised. One-way ANOVA was used to analyze data. Results revealed that there was statistically significant (P<0.05) difference in body weight change, CK-MB, and LDH across all experimental groups; which were significantly lower in cyclophosphamide group. Histology and Immunohistochemistry revealed that there were morphological alterations in the myocardium of the left ventricle in group B while turmeric extract ameliorated cyclophosphamide-induced damage in the myocardium in other experimental groups. In conclusion, cyclophosphamide-induced myocardial alterations were significantly ameliorated through administration of ethanol extract of turmeric.

Hypoactivity of rat detrusor muscle in a model of cystitis: exacerbation by non-selective COX inhibitors and amelioration by a selective DP1 receptor antagonist

Various studies have confirmed that prostaglandins (PG) alter the bladder motor activity and micturition reflex in both human and animals. However, no sufficient data is reported about the effect of cyclooxygenase (COX) inhibitors neither in normal bladder physiology nor in pathological conditions. This study aims to compare the potential effects of some COX inhibitors with varying COX-1/COX-2 selectivities (indomethacin, ketoprofen, and diclofenac) with that of the selective COX-2 inhibitor (DFU) on bladder function. The role played by some PGs and their receptors in controlling detrusor muscle function in normal condition and in cystitis is also studied. Organ bath experiments were performed using isolated rat detrusor muscle. Direct and neurogenic contractions were induced using ACh and electric stimulation (EFS), respectively. A model of hemorrhagic cystitis was induced by single injection of cyclophosphamide (300 mg/kg) in rats, and confirmed by histophathological examination. Results are expressed as mean ± SEM of 5-9 rats. Alprostadil and iloprost (1 nM- 10 µM) concentration-dependently potentiated ACh (100 μM)- and EFS (4 Hz)-induced contraction, with maximum potentiation of 40.01 ± 5.29 and 27.59 ± 6.64%, respectively, in case of ACh contractions. In contrast, ONO-AE1-259 (selective EP₂ agonist, 1 nM-10 μM) inhibited muscle contraction. SC51322 (EP₁-antagonist, 10 μM) and RO1138452 (IP antagonist, 10 μM) inhibited both direct and neurogenic responses. Hemorrhagic cystitis reduced both ACh and EFS responses as well as the potentiatory effect of iloprost and the inhibitory effect of RO1138452 on ACh contractions. ONO-AE3-237 (DP₁ antagonist, 1 μM) significantly potentiated contractions in cystitis but showed no effect in normal bladder. A significant inhibition of contractile response was observed in presence of indomethacin, ketoprofen, and diclofenac at all tested concentrations (20, 50, and 100 μM). Highest effect was induced by diclofenac. The effect of these COX inhibitors on EFS contractions was intensified in case of cystitis, indomethacin being the most potent. Atropine (1 nM) significantly reduced indomethacin effect on ACh contraction only in normal rats. On the other hand, DFU (10^-6 M) significantly potentiated the contractile effect of ACh in case of cystitis although it showed no effect in normal rats. EP₁ receptors seem to play an important role in rat bladder contractility. DP₁ receptors as COX-2, on the other hand, gain an important role only in case of cystitis. The use of non-selective COX inhibitors in cystitis may be associated with bladder hypoactivity; selective COX-2 inhibitors may be a safer option.

Protective Effect of Thymoquinone against Cyclophosphamide-Induced Hemorrhagic Cystitis through Inhibiting DNA Damage and Upregulation of Nrf2 Expression

Cyclophosphamide (CYP) induced hemorrhagic cystitis is a dose-limiting side effect involving increased oxidative stress, inflammatory cytokines and suppressed activity of nuclear factor related erythroid 2-related factor (Nrf2). Thymoquinone (TQ), an active constituent of Nigella sativa seeds, is reported to increase the expression of Nrf2, exert antioxidant action, and anti-inflammatory effects in the experimental animals. The present study was designed to explore the effects of TQ on CYP-induced hemorrhagic cystitis in Balb/c mice. Cystitis was induced by a single intraperitoneal injection of CYP (200 mg/kg). TQ was administered intraperitoneally at 5, 10 and 20 mg/kg doses twice a day, for three days before and three days after the CYP administration. The efficacy of TQ was determined in terms of the protection against the CYP-induced histological perturbations in the bladder tissue, reduction in the oxidative stress, and inhibition of the DNA fragmentation. Immunohistochemistry was performed to examine the expression of Nrf2. TQ protected against CYP-induced oxidative stress was evident from significant reduction in the lipid peroxidation, restoration of the levels of reduced glutathione, catalase and superoxide dismutase activities. TQ treatment significantly reduced the DNA damage evident as reduced DNA fragmentation. A significant decrease in the cellular infiltration, edema, epithelial denudation and hemorrhage were observed in the histological observations. There was restoration and rise in the Nrf2 expression in the bladder tissues of mice treated with TQ. These results confirm that, TQ ameliorates the CYP-induced hemorrhagic cystitis in mice through reduction in the oxidative stress, inhibition of the DNA damage and through increased expression of Nrf2 in the bladder tissues.

AMPK Suppresses Connexin43 Expression in the Bladder and Ameliorates Voiding Dysfunction in Cyclophosphamide-induced Mouse Cystitis

Bladder voiding dysfunction is closely related to local oxidation, inflammation, and enhanced channel activities. Given that the AMP-activated protein kinase (AMPK) has anti-oxidative, anti-inflammatory and channel-inhibiting properties, we examined whether and how AMPK affected bladder activity. AMPK activation in rat bladder smooth muscle cells (BSMCs) using three different AMPK agonists resulted in a decrease in connexin43 (Cx43) expression and function, which was associated with reduced CREB phosphorylation, Cx43 promoter activity and mRNA expression, but not Cx43 degradation. Downregulation of CREB with siRNA increased Cx43 expression. A functional analysis revealed that AMPK weakened BSMC contraction and bladder capacity. AMPK also counteracted the IL-1β- and TNFα-induced increase in Cx43 in BSMCs. In vivo administration of the AMPK agonist AICAR attenuated cyclophosphamide-initiated bladder oxidation, inflammation, Cx43 expression and voiding dysfunction. Further analysis comparing the responses of the wild-type (Cx43(+/+)) and heterozygous (Cx43(+/-)) Cx43 mice to cyclophosphamide revealed that the Cx43(+/-) mice retained a relatively normal micturition pattern compared to the Cx43(+/+) mice. Taken together, our results indicate that AMPK inhibits Cx43 in BSMCs and improves bladder activity under pathological conditions. We propose that strategies that target AMPK can be developed as novel therapeutic approaches for treating bladder dysfunction.

Crosstalk between nitric oxide synthases and cyclooxygenase 2 in the adrenal cortex of rats under lipopolysaccharide treatment

The effect of lipopolysaccharide on the modulation of steroid production by adrenal cells has been recently acknowledged. The purpose of this study was to determine the in vivo effects of LPS on adrenal cyclooxygenase 2 (COX-2) expression, analyze its crosstalk with the nitric oxide synthase (NOS) system, and assess its involvement on the modulation of glucocorticoid production. Male Wistar rats were injected with LPS and with specific inhibitors for NOS and COX activities. PGE2 and corticosterone levels were determined by RIA. Protein levels were analyzed by immunoprecipitation and western blotting. Transfection assays were performed in murine adrenocortical Y1 cells. Results show that LPS treatment increases PGE2 production and COX-2 protein levels in the rat adrenal cortex. Systemic inhibition of COX-2 blunted the glucocorticoid response to ACTH, as well as the increase in NOS activity and the NOS-2 expression levels induced by LPS. Conversely, NOS inhibition prevented the LPS-dependent increase in PGE2 production, COX-2 protein levels, and the nitrotyrosine modification of COX-2 protein. Treatment of adrenocortical cells with a NO-donor significantly potentiated the LPS-dependent increase in NFκB activity and COX-2 expression levels. In conclusion, our results show a significant crosstalk between COX-2 and NOS in the adrenal cortex upon LPS stimulation, in which each activity has a positive impact on the other. In particular, as both the activities differently affect adrenal steroid production, we hypothesize that this kind of fine modulation enables the gland to adjust steroidogenesis to prevent either an excessive or an insufficient response to the endotoxin challenge.

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.

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

Hemorrhagic cystitis (HC) is a common side effect observed in patients under chemotherapy with cyclophosphamide (CYP). The urotoxic side effects of CYP are attributed to the metabolic compound acrolein, and can be partially prevented by the uroprotector agent 2-mercaptoethene sulfate (Mesna). The present study analyzed the anti-inflammatory and the antinociceptive effects of compounds MV8608 and MV8612 obtained from Mandevilla velutina in the rat model of CYP-induced HC. Male Wistar rats were used (six to eight per group, 220-250 g). HC was induced by a single administration of CYP (100 mg/kg, ip). Three behavioral parameters--breathing rate, closing of the eyes, and specific posture--were used as nociception indexes, and scored at different time intervals (15-180 min) after cystitis induction. As inflammatory parameters, hemorrhage presence, edema formation, and bladder weight were determined at 24 h after CYP administration. The neutrophil migration was assessed by means of myeloperoxidase (MPO activity), 4 h after cystitis induction. As expected, Mesna treatment was able to reduce in a significant manner all the inflammatory and the nociceptive parameters induced by CYP. Of note, the administration of MV8608 significantly inhibited the hemorrhage formation and the neutrophil recruitment, while the MV8612 treatment markedly reduced the bladder weight, without interfering with neutrophil influx. Interestingly, the treatment with either MV8608 or MV8612 markedly reduced the nociceptive responses. The present results clearly indicate that MV8608 and MV8612 might represent important alternatives to prevent side effects, especially the nociception, following chemotherapy with CYP.

Gender-based reciprocal expression of transforming growth factor-beta1 and the inducible nitric oxide synthase in a rat model of cyclophosphamide-induced cystitis

BACKGROUND

The pluripotent cytokine transforming growth factor-beta1 (TGF-beta1) is the central regulator of inducible Nitric Oxide Synthase (iNOS) that is responsible for nitric oxide (NO) production in inflammatory settings. Previous studies have implicated a role for NO, presumably derived from iNOS, in cyclophosphamide (CYP)-induced cystitis in the bladder. TGF-beta1 is produced in latent form and requires dissociation from the latency-associated peptide (LAP) to act as primary anti-inflammatory and pro-healing modulator following tissue injury in the upper urinary tract. Since the role of TGF-beta1 in lower urinary tract inflammation is currently unknown, and since gender-based differences exist in the setting of interstitial cystitis (IC), the present study examined the relationship between TGF-beta1 and iNOS/NO in the pathogenesis of CYP-induced cystitis in both male and female rats.

METHODS

Sprague-Dawley rats, 4 months of age, of either gender were given 150 mg/kg CYP intraperitoneally. Urinary and bladder tissue TGF-beta1 and NO reaction products (NO2-/NO3-) were quantified as a function of time following CYP. Expression of active and latent TGF-beta1 as well as iNOS in harvested bladder tissue was assessed by immunohistochemistry.

RESULTS

Female rats had significantly higher levels of NO2-/NO3- in urine even at baseline as compared to male rats (p < 0.001), whereas there was no gender based significant difference in urine levels of active or latent TGF-beta1 prior to CYP injection. Inflammatory and cytotoxic changes were induced by CYP in the bladder of both sexes that were accompanied by differences in the urine levels of NO2-/NO3- and TGF-beta1. Male rats responded to CYP with significantly lower levels of NO2-/NO3- and significantly higher levels of TGF-beta1 in urine (p < 0.05) as compared to females at all time points after CYP. The urine levels of NO2-/NO3- after CYP were inversely correlated to latent and active TGF-beta1 (Pearson coefficient of -0.72 and -0.69 in females and -0.89 and -0.76 in males, respectively; p < 0.01). Bladder tissue of male rats exhibited significantly higher levels of both latent and active TGF-beta1 (p < 0.01) compared to female rats after CYP. TGF-beta1 and iNOS protein was mostly localized in the urothelium.

CONCLUSION

The results of this study suggest that there exists an inverse relationship between the expression of TGF-beta1 and iNOS/NO2-/NO3- in CYP-inflamed bladder. The gender of the animal appears to magnify the differences in urine levels of TGF-beta1 and NO2-/NO3- in this inflammatory setting. These results support the hypothesis that TGF-beta1 can suppress iNOS expression associated with bladder inflammation and reduce systemic levels of NO2-/NO3-, and further suggest that this feature of TGF-beta1 can be harnessed for therapy and diagnosis of interstitial cystitis.

Uroprotective effects of curcumin in cyclophosphamide-induced haemorrhagic cystitis paradigm

The possible uroprotective effects of curcumin have been addressed in the current study. Haemorrhagic cystitis was induced by challenging male Swiss albino rats with a single dose of cyclophosphamide (150 mg/kg, i.p.). Curcumin (200 mg/kg, i.p.) was administered for 10 consecutive days followed by a single dose of cyclophosphamide. Haemorrhagic cystitis was well characterized morphologically and biochemically. The hallmark of this toxicity was marked congestion, oedema and extravasation in rat urinary bladder, as well as a marked desquamative damage to the urothelium and severe inflammation in the lamina propria. Leucocytic infiltration was also observed and determined by histopathological examination. Serum level of tumour necrosis factor-alpha was notably elevated associated with apparent hypokalaemia and hyponatraemia. Bladder contents of adenosine triphosphate, reduced glutathione and glutathione-S-transferase activity were markedly reduced. Malondialdehyde level, myeloperoxidase activity and urinary nitrite-nitrate levels, expressed as nitric oxide, were dramatically increased. Prior administration of curcumin ahead of cyclophosphamide challenge improved all the biochemical and histologic alterations induced by the cytotoxic drug. Based on these broad findings, it could be concluded that curcumin has proven uroprotective efficacy in this cyclophosphamide haemorrhagic cystitis model, possibly through modulating the release of inflammatory endocoids, namely tumour necrosis factor-alpha and nitric oxide, improving the energy status and restoring the oxidant/antioxidant balance.

Aminoguanidine, selective nitric oxide synthase inhibitor, ameliorates cyclophosphamide-induced hemorrhagic cystitis by inhibiting protein nitration and PARS activation

OBJECTIVES

To elucidate the mechanism by which aminoguanidine (AG) protects against cyclophosphamide (CP)-induced hemorrhagic cystitis.

METHODS

Hemorrhagic cystitis was induced in the rats by administration of a single injection of CP at a dose of 150 mg/kg body weight intraperitoneally. For the AG pretreatment studies, the rats were injected intraperitoneally with AG at a dose of 200 mg/kg body weight 1 hour before administration of CP. The control rats received AG or saline alone. All the rats were killed 16 hours after the administration of CP or saline.

RESULTS

Pretreatment with AG ameliorated CP-induced bladder damage. Pretreatment with AG prevented CP-induced elevation in nitrate levels, nitration of protein tyrosine, poly (adenosine diphosphate ribose) polymerase (PARP) activation, and restored the activity of superoxide dismutase, the peroxynitrite-sensitive enzyme. The results of the present study have confirmed that AG is effective in preventing CP-induced cystitis and have also demonstrated that the protective effect is from its ability to inhibit nitric oxide-induced protein nitration and poly (adenosine diphosphate ribose) polymerase activation.

CONCLUSIONS

AG can prevent CP-induced urotoxicity and lead to better tolerance of the drug. Thus, a more efficient and comfortable therapy can be achieved for patients in need of CP treatment. AG appears to be a promising drug for the prevention of the urotoxicity of CP.

Protein nitration, PARP activation and NAD+ depletion may play a critical role in the pathogenesis of cyclophosphamide-induced hemorrhagic cystitis in the rat

OBJECTIVES

Hemorrhagic cystitis (HC) is a major dose-limiting side effect of cyclophosphamide (CP). The mechanism by which CP induces cystitis is not clear. Recent studies demonstrate that nitric oxide; (peroxynitrite) is involved in bladder damage caused by CP. However, the molecular targets of peroxynitrite are not known. The present study is aimed at investigating whether proteins and DNA are molecular targets of peroxynitrite using a rat model.

METHODS

The experimental rats received a single i.p. injection of 150 mg kg(-1) body weight CP in saline and killed 6 or 16 h later. The control rats received saline. The bladders were used for histological and biochemical analysis. Nitrotyrosine and poly-(ADP-ribose) polymerase (PARP) were localized immunohistochemically as indicators of protein nitration and DNA damage, respectively. Nitrite, malondialdehyde, protein thiol and superoxide dismutase (SOD) activity were assayed in the bladder.

RESULTS

Hematuria and urinary bladder edema was observed in the CP-treated rats and histologically, moderate to severe damage to the urinary bladder was observed. The bladders of CP-treated rats stained strongly for nitrotyrosine as well as for PARP. Significant decrease in oxidized NAD levels was observed in the bladders of CP-treated rats 16 h following treatment with CP. Protein thiol was depleted and the activity of the peroxynitrite sensitive enzyme SOD was significantly reduced in the bladders of CP-treated rats.

CONCLUSION

The results of the present study reveal that protein nitration, PARP activation and NAD+ depletion may play a critical role in the pathogenesis of CP-induced hemorrhagic cystitis. Based on the results we propose a mechanism for CP-induced cystitis.