Protective effect of taurine against cyclophosphamide-induced urinary bladder toxicity in rats

The effect of amino acids on the bladder cycle: a concise review

The human bladder maintains a cycle of filling, storing, and micturating throughout an individual's lifespan. The cycle relies on the ability of the bladder to expand without increasing the intravesical pressure, which is only possible with the controlled relaxation of well-complaint muscles and the congruously organized construction of the bladder wall. A competent bladder outlet, which functions in a synchronous fashion with the bladder, is also necessary for this cycle to be completed successfully without deterioration. In this paper, we aimed to review the contemporary physiological findings on bladder physiology and examine the effects of amino acids on clinical conditions affecting the bladder, with special emphasis on the available therapeutic evidence and possible future roles of the amino acids in the treatment of the bladder-related disorders.

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.

Role of taurine, its haloamines and its lncRNA TUG1 in both inflammation and cancer progression. On the road to therapeutics? (Review)

For one century, taurine is considered as an end product of sulfur metabolism. In this review, we discuss the beneficial effect of taurine, its haloamines and taurine upregulated gene 1 (TUG1) long non‑coding RNA (lncRNA) in both cancer and inflammation. We outline how taurine or its haloamines (N‑Bromotaurine or N‑Chlorotaurine) can induce robust and efficient responses against inflammatory diseases, providing insight into their molecular mechanisms. We also provide information about the use of taurine as a therapeutic approach to cancer. Taurine can be combined with other chemotherapeutic drugs, not only mediating durable responses in various malignancies, but also circumventing the limitations met from chemotherapeutic drugs, thus improving the therapeutic outcome. Interestingly, the lncRNA TUG1 is regarded as a promising therapeutic approach, which can overcome acquired resistance of cancer cells to selected strategies. In this regard, we can translate basic knowledge about taurine and its TUG1 lncRNA into potential therapeutic options directed against specific oncogenic signaling targets, thereby bridging the gap between bench and bedside.

The effects of tempol on cyclophosphamide-induced oxidative stress in rat micturition reflexes

We hypothesized that cyclophosphamide- (CYP-) induced cystitis results in oxidative stress and contributes to urinary bladder dysfunction. We determined (1) the expression of oxidative stress markers 3-nitrotyrosine (3-NT), reactive oxygen species (ROS)/reactive nitrogen species (RNS), inflammatory modulators, neuropeptides calcitonin gene-related peptide (CGRP), substance P (Sub P), and adenosine triphosphate (ATP) that contribute to the inflammatory process in the urinary tract and (2) the functional role of oxidative stress in urinary bladder dysfunction with an antioxidant, Tempol, (1 mM in drinking water) combined with conscious cystometry. In CYP-treated (4 hr or 48 hr; 150 mg/kg, i.p.) rats, ROS/RNS and 3-NT significantly (P ≤ 0.01) increased in urinary bladder. CYP treatment increased ATP, Sub P, and CGRP expression in the urinary bladder and cystometric fluid. In CYP-treated rats, Tempol significantly (P ≤ 0.01) increased bladder capacity and reduced voiding frequency compared to CYP-treated rats without Tempol. Tempol significantly (P ≤ 0.01) reduced ATP expression, 3-NT, and ROS/RNS expression in the urinary tract of CYP-treated rats. These studies demonstrate that reducing oxidative stress in CYP-induced cystitis improves urinary bladder function and reduces markers of oxidative stress and inflammation.

Oral glutamine attenuates cyclophosphamide-induced oxidative stress in the bladder but does not prevent hemorrhagic cystitis in rats

Cyclophosphamide (CP) is widely used in the treatment of cancer and non-malignant disease states such as rheumatoid arthritis. Hemorrhagic cystitis is a major dose-limiting side effect of CP. The incidence of this side effect is related to the dosage and can be as high as 75%. Elimination of the side effects of CP can lead to better tolerance of the drug, and a more efficient therapy can be achieved for patients in need of CP treatment. Several studies have demonstrated that oxidative stress and neutrophil infiltration play important roles in CP-induced bladder damage. Glutamine is utilized under clinical conditions for preventing chemotherapeutic drug-induced side effects, based on its ability to attenuate oxidative stress. The aim of the study is to verify whether glutamine prevents CP-induced oxidative stress and bladder damage using a rat model. Adult male rats were administered 150 mg/kg body weight of CP intraperitoneally. Glutamine pretreated rats were administered 1 g/kg body weight of glutamine orally 2 h before the administration of CP. Vehicle/glutamine-treated rats served as controls. All the rats were killed 16 h after the dose of CP/vehicle. The urinary bladders were removed and used for light microscopic and biochemical studies. The markers of oxidative stress including malondialdehyde content, protein carbonyl content, protein thiol, and myeloperoxidase activity, a marker of neutrophil infiltration, were measured in bladder homogenates. CP treatment induced hemorrhagic cystitis in the rats. Pretreatment with glutamine significantly reduced CP-induced lipid peroxidation (p < 0.01), protein oxidation (p < 0.01), and increase in myeloperoxidase activity (p < 0.05). However, it did not prevent CP-induced bladder damage. The results of the present study show that glutamine pretreatment does not attenuate CP-induced hemorrhagic cystitis, although it prevents CP-induced oxidative stress and neutrophil infiltration significantly. It is therefore necessary to clarify the utility of glutamine as a chemoprotective agent before it is recommended in the market as a nutrient supplement.

In Vivo Prevention of Bladder Urotoxicity

Urotoxicity is a troublesome complication associated with cyclophosphamide (CP) and L-buthionine-SR-sulfoximine (BSO) treatment in chemotherapy. With this concern in mind, the present study investigated the potential effects of a hydroxytyrosol extract from olive mill waste (OMW) on urotoxicity induced by acute CP and BSO doses using a Swiss albino mouse model. Toxicity modulation was evaluated by measuring lipid peroxidation (LPO) and antioxidants in urinary bladder. The findings revealed that the hydroxytyrosol extract exerted a protective effect not only on LPO but also on enzymatic antioxidants. When compared to the controls, the CP-treated animals underwent significant decreases in the glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GP), and catalase (CAT) activities. The level of glutathione (GSH) was also reduced with increased doses of LPO in the CP-treated animals. L-Buthionine-SR-sulfoximine treatment exerted an additive toxic effect on the CP-treated animals. Interestingly, pretreatment with the hydroxytyrosol extract restored the activities of all enzymes back to normal levels and exhibited an overall protective effect on the CP- and BSO-induced toxicities in urinary bladder. The restoration of GSH through the treatment with the hydroxytyrosol extract can play an important role in reversing CP-induced apoptosis and free radical-mediated LPO. 

Acacia Senegal gum exudate offers protection against cyclophosphamide-induced urinary bladder cytotoxicity

Cylophosphamide (CYCL) is a strong anticancer and immunosuppressive agent but its urotoxicity presents one of the major toxic effects that limit its wide usage particularly in high dose regimens. Therefore, this study aimed to investigate Acacia Senegal gum exudate, Gum Arabic (GA), for its possible role as a natural, nontoxic agent against CYCL-induced urotoxicity. Male Swiss albino rats were exposed to CYCL (150 mg/kg BW, once i.p) with or without GA oral supplementation (7.5 g/kg/day for 6 days) through drinking water. Glutathione (GSH), Malondialdehyde (MDA) and Nitric oxide (NO) bladder contents were assessed. Responsiveness of the bladder rings to acetylcholine (ACh) in vitro, microscopic and macroscopic features are also investigated. CYCL produced pronounced harmful effects on bladder urothelial lining with significant increases in (MDA) and NO levels in the tissue homogenates. Bladder-GSH content is dropped by over 60% following CYCL injection. Bladder contractility, as measured by its responsiveness to ACh, recorded a marked reduction. The isolated bladders exhibited such macroscopic changes as severe edema, inflammation and extravasation. The bladder weight increased as well. Histological changes were evident in the form of severe congestion, petechial hemorrhage and chronic inflammatory reaction in the lamina propria accompanied with desquamated epithelia. GA, a potential protective agent, produced an almost complete reversal of NO induction, lipid peroxidation or cellular GSH bladder contents in the GA + CYCL-treated group. Likewise, bladder inflammation and edema were reduced. Bladder rings showed a remarkable recovery in their responsiveness to ACh. Bladder histological examination showed a near normal configuration and structural integrity, with a significant reduction in inflammation and disappearance of focal erosions. These remarkable effects of GA may be attributed to its ability to neutralize acrolein, the reactive metabolite of CYCL and/or the resultant reactive oxygen metabolites, through a scavenging action. GA may limit the cascading events of CYCL-induced damage, initiating a cytoprotective effect leading to structural and functional recovery of the bladder tissues.

Tinospora cordifolia ameliorates urotoxic effect of cyclophosphamide by modulating GSH and cytokine levels

Cyclophosphamide (CP) is a commonly used anti-cancer drug which causes toxicity by its reactive metabolites. In this study we investigated the effect of Tinospora cordifolia on urotoxicity induced by acute dose of CP using Swiss albino mice model. Administration of an alcoholic extract of the plant T. cordifolia (Family: Menispermaceae) (200 mg/kg i.p.) for 5 days reduced CP (1.5 mmol/kg body wt. i.p.) induced urotoxicity as evident from the morphological analysis of bladder, decreased the relative bladder and liver weights and also decreased level of urea nitrogen and protein in blood as well as urine. Severely inflamed and dark coloured urinary bladders of the CP alone treated animals were found to be normalized by the treatment of T. cordifolia. GSH content, which was drastically reduced by CP administration in both bladder and liver was enhanced by treatment with T. cordifolia. Histopathological analysis of the bladder of CP alone-treated group showed severe necrotic damage where as the T. cordifolia-treated group showed normal bladder architecture. The lowered levels of cytokines IFN-γ, IL-2, after CP treatment were found to be increased in treated animals. At the same time the level of pro-inflammatory cytokine TNF-α, which was elevated during CP administration, was significantly reduced by extract administration. This study clearly demonstrates uroprotective role of T. cordifolia from CP induced toxicities by modulating GSH and pro-inflammatory cytokine levels.

Taurine ameliorates stress-induced degeneration of the urinary bladder

We studied the potential effects of taurine, a free radical scavenger, on chronic water avoidance stress (WAS)-induced degeneration of the mucosa of the urinary bladder in experimental rats. Wistar albino rats were exposed to WAS for 2h/day, for 5 days (WAS group). Before exposing them to WAS, taurine (50mg/kg) (WAS+taurine group) was injected intraperitonally into the animals. Samples of urinary bladder were then investigated by light and scanning electron microscopy. Lipid peroxidation and gluthathione levels were also measured in the urinary bladder. In the WAS-only group, inflammatory cell infiltration, increased number of mast cells in the mucosa and ulcerated areas were observed. In the WAS+taurine group, relatively normal urothelial topography with microvilli, moderate inflammatory cell infiltration and decreased numbers of mast cells in the mucosa were observed. The increased lipid peroxidation and decreased glutathione levels in WAS rats were reversed by taurine treatment. We conclude that taurine protects against WAS-induced oxidant urinary bladder injury, and thus may be a possible therapeutic agent against interstitial cystitis, the symptoms of which are aggravated by stress conditions.

Aqueous extract of Trigonella foenum-graecum L. ameliorates additive urotoxicity of buthionine sulfoximine and cyclophosphamide in mice

Cyclophosphamide (CP) is a commonly used anti-cancer drug which causes toxicity by its reactive metabolites such as acrolein and phosphoramide mustard. In the present study modulation of toxicity caused by concomitant exposure to CP and l-buthionine-SR-sulfoximine (BSO) by fenugreek (Trigonella foenum-graecum L.) extract was evaluated by measuring lipid peroxidation (LPO) and anti-oxidants in urinary bladder in mice. Fenugreek, a common dietary and medicinal herb, showed protective effect not only on LPO but also on the enzymatic anti-oxidants. CP-treated animals exhibited a significant decrease in the activities of glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GP) and catalase (CAT) when compared to the controls. Level of reduced glutathione (GSH) was also reduced with an increase in LPO in CP-treated animals. BSO treatment depicted an additive toxic effect in CP-treated animals. Pre-treatment of herbal extract restored activities of all the enzymes and thus showed an overall protective effect on additive effect of CP and BSO. Restoration of GSH by extract treatment may play an important role in reversing CP-induced apoptosis and free radical-mediated LPO in urinary bladder. Fenugreek, known for its hypoglycemic, anti-inflammatory and immunomodulatory activity, may be a promising protective medicinal herb for consideration in complementary therapy in cancer patients under chemotherapeutic interventions.

Protective effects of taurine on protamine sulfate induced bladder damage

The present study was designed to investigate the putative protective effects of taurine on protamine sulfate (PS) induced bladder injury. Wistar albino female rats were catheterized and intravesically infused with phosphate buffered solution (control group) or PS (PS group) dissolved in phosphate buffered solution. In the PS + taurine (PS+Tau) group, after the PS instillation, taurine (50 mg/kg) was injected intraperitoneally for 3 days. Histopathological changes were investigated by light and scanning electron microscopy. Tissue samples were also obtained to determine bladder malondialdehyde (MDA) (a biomarker of oxidative damage) and glutathione (GSH) (a biomarker of protective oxidative injury) levels. In the PS group ulcerated areas, an irregular mucus layer, inflammatory cell infiltration, and increased number of mast cells were observed. In the PS+Tau group, a relatively normal urothelial topography, glycosaminoglycan layer, and decreased number of mucosal mast cells and inflammatory cells were observed. Increased MDA levels as a result of PS induction lead us to propose that free radicals may have a critical role in this injury. The significant decrease in MDA and increase in GSH levels in the PS+Tau group compared to PS group was in accordance with morphological findings. Based on the results, taurine treatment significantly prevented PS induced degenerative morphological and biochemical changes of urinary bladder mucosa.