Protective Effects of Taurine against Nicotine-Induced Oxidative Damage of Rat Urinary Bladder and Kidney

Several studies demonstrate that taurine treatment prevents tissue damage in various models of inflammation. Experiments have shown that chronic nicotine administration caused oxidant damage in various organs by increasing lipid peroxidation products and decreasing the activity of endogenous antioxidants. The aim of this study was to investigate the effects of taurine treatment on nicotine-induced oxidative changes in rat urinary bladder and kidney and to explore the possible mechanisms of action. Male Wistar albino rats were injected with nicotine hydrogen bitartrate (0.6 mg/kg i.p.) or saline for 21 days. Taurine was administered (50 mg/kg i.p.) alone or along with nicotine injections. At the end of the treatment period bladder tissue was used for in vitro contractility studies, or stored along with kidney tissue for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Tissue samples were also examined histologically. Serum samples were stored for the measurement of MDA, GSH, blood urea nitrogen, creatinine and lactate dehydrogenase activity. Chronic nicotine treatment decreased the contractile activity of the bladder strips to carbachol and increased lipid peroxidation, MPO levels and tissue collagen content of the bladder and kidney samples. Taurine supplementation to nicotine-treated animals reversed the contractile dysfunction of the bladder strips. It also preserved the renal functions, restored the endogenous GSH levels and decreased high lipid peroxidation and MPO activities in both urinary bladder and kidney tissues. These data suggest that taurine supplementation effectively counteracts the deleterious effect of chronic nicotine administration on bladder and kidney functions and attenuates oxidative damage possibly by its antioxidant effects.

Taurine treatment protects against chronic nicotine-induced oxidative changes

Experiments have shown that chronic nicotine administration caused oxidative damage in various organs by increasing lipid peroxidation products and decreasing the activity of endogenous antioxidants. The aim of this study was to investigate the effects of taurine treatment on nicotine-induced oxidative changes in rat thoracic aorta and heart and to explore the possible mechanisms of action. Male Wistar albino rats (200-250 g) were injected with nicotine hydrogen bitartrate (0.6 mg/kg; i.p.) or saline for 21 days. Taurine was administered (50 mg/kg; i.p.) alone or along with nicotine injections. After decapitation, the thoracic aorta and heart tissues were excised. The aorta was used for in vitro contractility studies or stored along with the heart samples for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Tissue samples were also examined histologically. Serum samples were stored for the measurement of MDA, GSH and lactate dehydrogenase (LDH) activity. Chronic nicotine treatment impaired both the contraction and relaxation responses of the aortic rings to phenylephrine and acetylcholine, respectively. It increased lipid peroxidation, MPO levels and tissue collagen content of both aorta and heart samples. Taurine supplementation to nicotine-treated animals reversed the contractile dysfunction and restored the endogenous GSH levels and decreased high lipid peroxidation and MPO activities in both tissues. These data suggest that taurine supplementation effectively attenuates the oxidative damage because of chronic nicotine administration possibly by its antioxidant effects.

Role of melatonin in reducing water avoidance stress-induced degeneration of the liver

Melatonin, a pineal secretory product, is a potent scavenger of a variety of free radicals. We investigated the role of melatonin on water avoidance stress (WAS)-induced degenerations of the liver parenchyme. Wistar albino rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing animals to acute (aWAS + mel group) or chronic WAS (cWAS + mel group), 10 mg/kg melatonin was injected i.p. The liver samples were investigated under light and transmission electron microscope. Malondialdehyde (MDA) and glutathione (GSH) levels were also determined. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells with prominent morphology, dilated granular endoplasmic reticulum membranes, and focal picnotic nuclei were observed in the aWAS group; these morphological changes were severe in the cWAS group. MDA level was increased and GSH level was decreased significantly in the cWAS group. The morphology of liver parenchme in both the aWAS + mel and the cWAS + mel group showed that melatonin significantly reduced the degeneration in liver; besides, a significant decrease in MDA and an increase in GSH levels were observed in the cWAS + mel group. Based on the results, melatonin treatment significantly prevented WAS-induced morphological and biochemical changes in liver parenchyma.

Effect of aging on the distribution of basic fibroblast growth factor immunoreactive cells in the rat hippocampus

Hippocampal formation is extremely sensitive to the aging process and appears to be one of the first regions to show structural and physiological changes with advancing age. Basic fibroblast growth factor (bFGF) plays an important role in the stimulation of mitogenesis in glial cells, the support of neuronal survival and the promotion of neurite outgrowth in vitro. In the present study, the effect of aging on the distribution of bFGF immunoreactive (bFGF-ir) cells was investigated. The protein product of bFGF was visualized immunohistochemically in the dorsal hippocampus of Wistar albino rats. bFGF-ir astrocytes in different subfields of hippocampus and neurons in CA2 field were quantified to determine whether changes in immunoreactivity were correlated with advancing age. Aging was accompanied by a decrease in bFGF-ir cell density in subfields of hippocampus. We concluded that aging was associated with a reduction in bFGF-ir cell density that may reflect a decreased expression of bFGF in the rat hippocampus.

Octreotide ameliorates sepsis-induced pelvic inflammation in female rats by a neutrophil-dependent mechanism

Sepsis is a generalized inflammatory response, which involves organ systems remote from the locus of the initial infectious insult, accompanied by the release of cytokines and the subsequent formation of reactive oxygen and nitrogen species. The aim of this study was to investigate the possible protective effect of octreotide (OCT), a synthetic somatostatin analogue, against sepsis-induced oxidative damage in the uterine and ovarian tissues of rats. Sepsis was induced by caecal ligation and puncture method in female Wistar albino rats. Sepsis and sham operated (control) groups received either saline or OCT (50 microg/kg, i.p.; Novartis) immediately after the operation and at 12 h. Twenty-four hours after the surgery, rats were decapitated and serum TNF-alpha levels and tissue malondialdehyde (MDA) content, glutathione (GSH) levels and myeloperoxidase (MPO) activity were determined in the uterus and ovaries. Oxidant-induced tissue fibrosis was determined by tissue collagen contents, while the extent of tissue injuries was analyzed microscopically. Sepsis increased serum TNF-alpha levels and resulted in decreased GSH levels and increased MDA levels, MPO activity and collagen contents in both the uterus and the ovaries (p<0.05-0.001) indicating the presence of the oxidative damage, as also confirmed by histological analysis. On the other hand, OCT administration reversed these oxidant responses and reduced the severity of microscopic damage (p<0.001). In conclusion, OCT protects against sepsis-induced oxidative injury of the uterine and ovarian tissues by diminishing neutrophil infiltration, an important source of oxygen free radicals. Our results suggest that OCT may be of therapeutic value in ameliorating sepsis-associated pelvic inflammation.

The protective effects of melatonin against water avoidance stress-induced mast cell degranulation in dermis

Nontraumatic psychological water avoidance stress has been shown to induce mucosal degeneration, inflammatory cell infiltration and mast cell degranulation in stomach, ileum, colon and urinary bladder. Many skin disorders, such as atopic dermatitis and psoriasis, worsen during stress and seem to be related with infiltration and activation of mast cells releasing vasoactive and proinflammatory mediators. Melatonin is a free radical scavenger and has cytoprotective effects in inflammatory conditions. The aim of the present study was to investigate the effects of melatonin on water avoidance stress (WAS)-induced degranulation of mast cells in the dermis. Wistar rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing to acute WAS, one group of animals was treated with 10mg/kg melatonin (aWAS+mel group). In the cWAS+mel group, treatment with melatonin lasted for 5 days. Dermal mast cells were stained with toluidine blue and investigated using light microscopy. Numbers of mast cells were increased in both aWAS and cWAS groups, but numbers of degranulated mast cells were increased significantly only in the cWAS group when compared to the control group. Numbers of mature granulated and degranulated mast cells were decreased in the cWAS+mel group when compared to the cWAS group. In conclusion, chronic melatonin treatment reduced WAS-induced infiltration and activation of mast cells in dermis and may provide a useful therapeutic option in stress-induced skin disorders.

Protective effect of melatonin on water avoidance stress induced degeneration of the bladder

PURPOSE

The role of melatonin on chronic water avoidance stress (WAS) induced degeneration of bladder epithelium (urothelium) was investigated.

MATERIALS AND METHODS

Wistar albino rats were exposed to WAS for 2 hours daily for 5 days (WAS group). Before exposing them to WAS 10 mg/kg melatonin (WAS plus melatonin group) was injected intraperitoneally into the animals. Bladder samples were investigated with light and electron microscopy. Lipid peroxidation and glutathione levels were also measured in the bladder.

RESULTS

In the WAS only group an increased number of mast cells in the mucosa, ulcerated areas, vacuole formation and dilated perinuclear cisternae, and dilatation in the intercellular spaces in the urothelium were observed. In the WAS plus melatonin group relatively normal urothelial topography, a decreased number of mast cells in the mucosa, some dilatation between intercellular areas, regular perinuclear cisternae and tight junctions were observed. Increased lipid peroxidation and decreased glutathione levels in WAS rats were reversed by melatonin.

CONCLUSIONS

The results show that melatonin reverses WAS induced degenerative changes in the bladder.

Gastroprotective effect of leukotriene receptor blocker montelukast in alendronat-induced lesions of the rat gastric mucosa

Alendronate causes serious gastrointestinal adverse effects. We aimed to investigate if montelukast, a leukotriene receptor antagonist, is protective against this damage. Rats were administered 20 mg/kg alendronate by gavage for 4 days, either alone or following treatment with montelukast (10 mg/kg). On the last day, following drug administration, pilor ligation was performed and 2 h later, rats were killed and stomach, liver and kidney tissues were removed. Gastric acidity, gastric tissue ulcer index values and malondialdehyde (MDA); an end product of lipid peroxidation, and glutathione (GSH) levels; a key antioxidant, as well as myeloperoxidase (MPO) activity; an indirect marker of tissue neutrophil infiltration were determined, and the histologic appearance of the stomach, liver and kidney tissues were studied. Chronic oral administration of alendronate induced significant gastric damage, increasing myeloperoxidase activity and lipid peroxidation, while tissue glutathione levels decreased. Similarly, in the alendronate group MDA levels and MPO activities of liver and kidney tissues were increased and GSH levels were decreased. Treatment with montelukast prevented the damage as well as the changes in biochemical parameters in all tissues studied. Findings of the present study suggest that alendronate is a local irritant that causes inflammation through neutrophil infiltration and oxidative damage in tissues, and that montelukast is protective against this damage by its anti-inflammatory effect.

Collagen ultrastructure and TGF-beta1 expression preserved with aminoguanidine during wound healing in diabetic rats

Advanced glycoxidation end products have been implicated in delayed diabetic wound healing. In this study, we evaluated the effects of aminoguanidine, which is an advanced glycation and nitric oxide (NO) synthase inhibitor, on extracellular matrix protein expression, collagen configuration, and nitrite/nitrate levels in wounds of diabetic rats. Sixteen Wistar male rats were made diabetic by streptozotocin. Of these, eight rats were given AG (aminoguanidine bicarbonate (AG) (group DAG) in their drinking water, and eight rats were followed as diabetic paired controls (group D). Eight healthy rats were followed as the healthy control group (group H). At the eighth week, a 2 x 2 cm area full-thickness skin defect was created. The degree of contraction of the open wounds was evaluated for 2 weeks duration. On the 15th postoperative day, wound surface areas were measured, and wound specimens and blood samples were collected. The shrinking percentage of the wounds was small in both groups H and DAG compared with group D (p < 0.05). Similar to healthy rats, the aminoguanidine-treated diabetic rats had very strong transforming growth factor (TGF)-beta1 expression in granulation tissue and intact skin in comparison with diabetic controls. In the diabetic group, the intact skin demonstrated sparsely distributed regular collagen fibers in the granulation zone, and the regular pattern of collagen fibers was lost. In conclusion, aminoguanidine improves wound healing, restores growth factor TGF-beta1 expression, and preserves collagen ultra structure, whereas it has no prominent effect on NO levels within wound tissue in diabetic rats.

Protective effects of MESNA (2-mercaptoethane sulphonate) against acetaminophen-induced hepatorenal oxidative damage in mice

Acetaminophen, a widely used analgesic and antipyretic, is known to cause hepatic and renal injury in humans and experimental animals when administered in high doses. It was reported that these toxic effects of acetaminophen are due to oxidative reactions that take place during its metabolism. In this study we aimed to investigate the possible beneficial effect of 2-mercaptoethane sulphonate (MESNA), an antioxidant agent, against acetaminophen toxicity in mice. Balb-c mice were injected i.p. with: vehicle (the control group); a single dose of 150 mg kg(-1) MESNA (MES group); a single dose of 900 mg kg(-1) i.p. acetaminophen (AA4h and AA24h groups); and MESNA, at a dose of 150 mg kg(-1) after acetaminophen injection (AA4h-MES and AA24h-MES groups). The MESNA injection was repeated once more 12 h after the first injection in the AA24h-MES group. Blood urea nitrogen, serum creatinine, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in blood and glutathione (GSH) and malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity and collagen contents in liver and kidney tissues were measured. Tissues also were examined microscopically. Blood urea nitrogen and serum creatinine, which were increased significantly (P < 0.001) following acetaminophen treatment were decreased significantly (P < 0.05-0.001) after treatment with MESNA. The ALT and AST levels were also increased significantly (P < 0.001) after acetaminophen treatment but were not reduced with MESNA. Acetaminophen treatment caused a significant (P < 0.05-0.001) decrease in GSH levels whereas MDA levels and MPO activity were increased in both tissues. These changes were reversed by MESNA treatment. Collagen contents of the liver and kidney tissues were increased by acetaminophen treatment (P < 0.001) and reversed back to the control levels with MESNA. Our results imply that acetaminophen causes oxidative damage in hepatic and renal tissues and that MESNA, via its antioxidant effects, protects these tissues. Therefore, its therapeutic role as a 'tissue injury-limiting agent' must be elucidated further in drug-induced oxidative damage.

Endothelin-3 induced mesenteric vasoconstriction and PMN infiltration in the rat small intestine: role of endothelin receptors

The objectives of this study were to characterize endothelin (ET)-3-induced alterations in intestinal hemodynamics and to evaluate whether ET-3 administration alters the tissue levels of polymorphonuclear leukocytes (PMNs) and modulates the epithelial barrier function of the small intestine. ET-3 (100 pmol/kg/min) was infused into the superior mesenteric artery (SMA) for 10 min, and tissue samples were obtained 30 min after terminating the infusion. SMA blood flow was significantly decreased throughout the experiment following ET-3 infusion. Pretreatment with bosentan (ET-A and ET-B receptor antagonist), ET-B receptor antagonist BQ-788 or ET-A receptor antagonist BQ-485 completely inhibited the ET-3-induced decrease in the SMA blood flow. Similar results were obtained from the resistance data, in which ET-3-induced increases in SMA resistance were significantly reduced by all ET receptor antagonists. ET-3 administration significantly elevated tissue MPO activity, blood-to-lumen clearance of (51)Cr-EDTA and caused a marked microscopic damage in the intestinal mucosa. ET-3-induced elevations in tissue PMN infiltration and mucosal damage were significantly inhibited by pretreatments with ET-A or ET-B receptor antagonists. Overall, our data indicate that ET-3 causes microscopic damage, PMN infiltration and mucosal dysfunction in the rat small intestine. In addition, ET-3-induced hemodynamic alterations as well as tissue PMN infiltration and mucosal damage are mediated by both ET-A and ET-B receptors.

2-Mercaptoethane sulfonate (MESNA) protects against burn-induced renal injury in rats

Animal models of thermal injury implicate oxygen radicals as causative agents in local wound response and distant organ injury following burn. In this study we investigated the putative protective effects of 2-mercaptoethane sulfonate (MESNA) against oxidative kidney damage in rats with thermal injury. Under ether anaesthesia, shaved dorsum of the rats was exposed to 90 degrees C bath for 10s to induce burn injury. Rats were decapitated either 6 or 24h after burn injury. MESNA was administered i.p. immediately after burn injury. MESNA injections were repeated once more 12h after the first injection in the 24h burn group. In the control group the same protocol was applied except that the dorsum was dipped in a 25 degrees C water bath for 10s. Kidney tissues were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, protein oxidation (PO), myeloperoxidase (MPO) activity and collagen contents. Creatinine, urea concentrations (BUN) and lactate dehydrogenase (LDH) in blood were measured for the evaluation of renal functions and tissue damage, respectively. Tissues were also examined microscopically. Severe skin scald injury (30% of total body surface area) caused significant decrease in GSH level, significant increase in MDA level, protein oxidation (PO), MPO activity and collagen content of renal tissue. Serum creatinine was slightly increased at the early phase of thermal trauma but not changed in 24h groups. On the other hand BUN and LDH were significantly elevated by thermal trauma in both 6 and 24h of burn groups. Treatment of rats with MESNA significantly increased the GSH level and decreased the MDA level, PO, MPO activity, collagen contents, BUN and LDH. Since MESNA reversed the oxidant responses seen in burn injury, it seems likely that MESNA could protect against thermal trauma-induced renal damage.

Mesna (2-mercaptoethane sulfonate) prevents ischemia/reperfusion induced renal oxidative damage in rats

Reoxygenation of the ischemic tissue promotes the generation of various reactive oxygen metabolites (ROM) which are known to have deleterious effects on various cellular functions. This study was designed to determine the possible protective effect of mesna (2-Mercaptoethane Sulfonate) on renal ischemia/reperfusion (I/R) injury. Wistar albino rats were unilaterally nephrectomized, and 15 days later they were subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Mesna (MESNA, 150 mg/kg, i.p.; an effective dose against I/R injury) or vehicle was administered twice, 15 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were killed by decapitation. Kidney samples were taken for histological examination or determination of the free radicals, renal malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. Renal tissue collagen content, as a fibrosis marker was also determined. Creatinine and urea concentrations in blood were measured for the evaluation of renal function. The results demonstrated that renal I/R caused nephrotoxicity, as evidenced by increases in blood urea and creatinine levels, which was reversed by MESNA treatment. Increased free radical levels, as assessed by nitroblue-tetrazolium test were reduced with MESNA. Moreover, the decrease in GSH and increases in MDA levels, and MPO activity induced by I/R indicated that renal injury involves free radical formation. Treatment of rats with MESNA restored the reduced GSH levels while it decreased MDA levels as well as MPO activity. Increased collagen contents of the kidney tissues by I/R were reversed back to the control levels by MESNA treatment. Since MESNA administration reversed these oxidant responses, improved renal function and microscopic damage, it seems likely that MESNA protects kidney tissue against I/R induced oxidative damage.

Role of melatonin in reducing water avoidance stress-induced degeneration of the gastrointestinal mucosa

We investigated the role of melatonin on water avoidance stress (WAS)-induced degeneration of the gastric, ileal and colonic mucosa. Wistar albino rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing animals to acute (aWAS + mel group) or chronic WAS (cWAS + mel group), 10 mg/kg melatonin was injected i.p. The stomach, ileum and colon samples were investigated under light and scanning electron microscope. Malondialdehyde (MDA) and glutathione (GSH) levels were also determined. In both aWAS and cWAS groups, the epithelium of stomach showed ulceration in some areas, dilatations of the gastric glands and degeneration of gastric glandular cells; prominent congestion of the capillaries after WAS was apparent. In the cWAS group, severe vascular congestion was observed along with degeneration of ileal and colonic epithelium. MDA levels were increased and GSH levels were decreased in all tissues in both the aWAS and cWAS groups. The morphology of gastric, ileal and colonic mucosa in both aWAS + mel and cWAS + mel groups showed that the indole significantly reduced degeneration of the gastrointestinal mucosa. Decreased MDA and increased GSH levels were observed in the WAS + mel groups. Based on the results, melatonin treatment significantly prevented WAS induced degenerative morphological and biochemical changes of gastrointestinal mucosa.

Melatonin attenuates ifosfamide-induced Fanconi syndrome in rats

Regarding the mechanisms of ifosfamide (IFO)-induced nephrotoxicity and hemorrhagic cystitis, several hypotheses have been put forward, among which oxidative stress and depletion of glutathione (GSH) are suggested. This investigation elucidates the role of free radicals in IFO-induced toxicity and the protection by melatonin. Wistar albino rats were injected intraperitoneally with saline (0.9% NaCl; control-C group), melatonin (Mel group; 10 mg/kg daily for 5 days) or ifosfamide (50 mg/kg daily for 5 days; IFO group) or IFO + Mel. On the 5th day (120 hr) after the first IFO dose, animals were killed by decapitation and trunk blood was collected. Kidney and bladder tissues were obtained for biochemical and histological analysis. Urine was collected 24 hr before the rats were killed. The results demonstrated that IFO induced a Fanconi syndrome (FS) characterized by wasting of sodium, phosphate, and glucose, along with increased serum creatinine and urea. Melatonin markedly ameliorated the severity of renal dysfunction induced by IFO with a significant decrease in urinary sodium, phosphate, and glucose and increased creatinine excretion. Moreover, melatonin significantly improved the IFO-induced GSH depletion, malondialdehyde accumulation and neutrophil infiltration in both renal and bladder tissues. In the kidney, Na+,K+ -ATPase activity which was significantly reduced by IFO, was increased with melatonin treatment. Increased collagen contents of the kidney and bladder tissues by IFO treatment were reversed back to the control levels with melatonin. Our results suggest that IFO causes oxidative damage in renal and bladder tissues and melatonin, via its antioxidant effects, protects these tissues. These data suggest that melatonin may be of therapeutic use in preventing acquired FS due to IFO toxicity.

Blood flow alterations in TNBS-induced colitis: role of endothelin receptors

OBJECTIVES

The aim of the present study was to investigate the time dependent changes in hemodynamic parameters and to assess the role of endothelin (ET) receptors in trinitrobenzene sulfonic acid (TNBS) induced colitis.

MATERIALS

Inferior mesenteric artery (IMA) hemodynamics, myeloperoxidase activity (MPO) and damage scores were measured immediately or 1, 3, 5 and 14 days after colitis.

TREATMENTS

Another group of rats received a nonselective ET receptor antagonist bosentan (30 mg/kg/day), ET-A receptor antagonist BQ485 (60 microg/rat/day) or ET-B receptor antagonist BQ788 (60 microg/rat/day) prior to and on the 1st, 2nd and 3rd days after TNBS administration.

RESULTS

IMA flow significantly increased at 90 min followed by a substantial decrease through days 1-5. Tissue MPO activity and macroscopic damage score increased on 1st day after the induction of colitis and remained elevated 3, 5 and 14 days following colitis. Treatment with bosentan or ET-A receptor antagonist largely prevented the colitis-induced reduction in blood flow and tissue injury whereas ET-B receptor antagonist did not attenuate tissue injury or reductions in blood flow.

CONCLUSIONS

Our results demonstrate that time-dependent abnormalities occur in IMA hemodynamics following TNBS administration. Our findings also indicate that ET-A receptors but not ET-B receptors play an important role in the colonic inflammation following TNBS administration.

Octreotide ameliorates alendronate-induced gastric injury

Alendronate causes serious gastrointestinal adverse effects. The aim of this study was to investigate whether octreotide, a synthetic somatostatin analogue, improves the alendronate-induced gastric injury. Rats were administered 20mg/kg alendronate by gavage for 4 days, either alone or following treatment with octreotide (0.1 ng/kg, i.p.). On the last day, following drug administration, pilor ligation was performed and 2h later, rats were killed and stomachs were removed. Gastric acidity and tissue ulcer index values, lipid peroxidation (as assessed by malondialdehyde, MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity as well as the histologic appearance of the stomach tissues were determined. Chronic oral administration of alendronate induced significant gastric damage, increasing lipid peroxidation (37.1+/-3.2 nmol/g) and myeloperoxidase activity (57.6+/-3.7 U/g), while tissue glutathione levels (09.+/-0.1 micromol/g) decreased. Treatment with octreotide prevented this damage as well as the changes in biochemical parameters (MDA: 23.4+/-1.3 nmol/g; MPO: 31.68 U/g; GSH: 15.+/-0.1 micromol/g). Findings of the present study suggest that alendronate induces oxidative gastric damage by a local irritant effect, and that octreotide ameliorates this damage by inhibiting neutrophil infiltration and reducing lipid peroxidation. Therefore, its therapeutic role as a "ulcer healing" agent must be further elucidated in alendronate-induced gastric mucosal injury.

Volume of Nerve Fibers in the Stress-Induced Bladder of Adult Rats following Capsaicin Treatment

INTRODUCTION

We have investigated the volume of nerve fibers in the rat urinary bladder following systematic exposure to cold-restraint stress and capsaicin treatment.

MATERIALS AND METHODS

Adult Wistar albino rats were either exposed to cold-restraint stress (vehicle group) or treated with capsaicin before exposure to cold-restraint stress (capsaicin group). In the control group, animals were neither exposed to cold-restraint stress nor given capsaicin. From each group, samples of bladder were prepared for morphological investigation and stereological evaluation of the volume of nerve fibers.

RESULTS

Stress exposure was associated with urothelial degeneration, a higher incidence and degranulation of mast cell profiles in the mucosa, and an increased volume of nerve fibers in the muscular layer of the bladder wall. Capsaicin treatment prevented the stress-induced degenerative changes. In the capsaicin group, the volume of nerve fibers in the muscular layer was also significantly smaller than that in the stress group.

CONCLUSIONS

Exposure of adult rats to capsaicin prevented the stress-induced degeneration of the bladder and changed the volume of capsaicin-sensitive fibers in muscular layer. We conclude that capsaicin and related compounds may be useful in treating stress-induced bladder problems.

The Use of Transversely Tubularized Bowel Segment for Segmental Ureteral Replacement

The aim of the present study was to evaluate the results of the use of a new technique, i.e. transversely tubularized bowel segment (TTBS) for segmental ureteral replacement in pigs. Eight pigs had segmental left ureteral replacement with the TTBS technique, via midline incision in 5 and flank incision in 3. The right ureters were left untouched and used as controls. The pigs were evaluated by excretory urography approximately 3 months after surgery and then sacrificed thereafter, harvesting the kidneys, ureters, and the bladders en bloc for macroscopic and histologic examination. Three pigs died in the early postoperative period. The remaining 5 pigs were followed for 82-112 days. Postoperative intravenous urograms revealed moderate ureterohydronephrosis in 2, mild ureteral dilation in 1, and normal upper tracts in 2. The 2 pigs with moderate ureterohydronephrosis had had midline incisions, and examination after having sacrificed these pigs revealed many intestinal adhesions to the anastomotic region. Easy catheterization of each left ureter through ileal ureteral segment and histologic examination thereafter demonstrated that all ileal ureteral segments including anastomotic sites were patent. Adjacent to the junctional area, metaplastic transitional epithelium covered atrophic villi and in some regions crypts as well. Ureteral replacement by the TTBS technique seems to be a safe and effective surgical treatment option in segmental ureteral defects in short term. However, long-term follow-up studies are needed.

The ameliorating effect of melatonin on protamine sulfate induced bladder injury and its relationship to interstitial cystitis

PURPOSE

The pineal hormone melatonin was recently shown to have free radical scavenging ability and it reduces lipid peroxidation. In this morphological study we investigated the effects of melatonin on protamine sulfate (Sigma Chemical Co., St. Louis, Missouri) induced bladder injury.

MATERIALS AND METHODS

Albino Wistar female rats were catheterized and intravesically infused with phosphate buffered solution (control group) or protamine sulfate (bladder injury group) dissolved in phosphate buffered solution. In the protamine sulfate plus melatonin group after protamine sulfate instillation melatonin was injected intraperitoneally. Bladder morphology was investigated by light and electron microscopy. Tissue samples were also obtained to determine bladder malondialdehyde levels.

RESULTS

In the bladder injury group ulcerated areas, an irregular glycosaminoglycan layer, increased number of mast cells, vacuole formation, dilated perinuclear cistern, formation of pleomorphic and uniform microvilli, and dilated urothelial intercellular spaces were observed. In the bladder injury plus melatonin group a relatively normal urothelial topography, glycosaminoglycan layer and decreased number of mucosal mast cells, some dilatation between intercellular areas, less uniform microvilli and in most areas regular tight junctions were observed.

CONCLUSIONS

Increased malondialdehyde levels as a result of protamine sulfate induction lead us to propose that free radicals may have a critical role in this injury. The significant decrease in malondialdehyde levels in the protamine sulfate plus melatonin group was in accordance with morphological findings. Thus, melatonin appears to exert a urothelial protective activity in a bladder injury model.

Indomethacin-induced morphologic changes in the rat urinary bladder epithelium

OBJECTIVES

To evaluate the morphologic changes in rat urothelium induced by indomethacin. Nonsteroidal anti-inflammatory drug-induced cystitis is a poorly recognized and under-reported condition. In addition to tiaprofenic acid, indomethacin has been reported to be associated with this condition.

METHODS

Three groups were established: a control group (n = 10), a high-dose group (n = 10), treated with one intraperitoneal injection of indomethacin 20 mg/kg, and a therapeutic dose group (n = 10) in which oral indomethacin was administered 3.25 mg/kg body weight daily for 3 weeks. The animals were then killed and the bladders removed for light and electron microscopic studies.

RESULTS

The light microscopic findings showed some focal epithelial degeneration that was more prominent in the high-dose group. When compared with the control group, both indomethacin groups revealed statistically increased numbers of mast cells in the mucosa (P <0.0001) and penetration of lanthanum nitrate through intercellular areas of the epithelium. Furthermore, the difference in mast cell counts between the high and therapeutic dose groups was also statistically significant (P <0.0001).

CONCLUSIONS

Indomethacin resulted in histopathologic findings typical of interstitial cystitis, such as leaky bladder epithelium and mucosal mastocytosis. The true incidence of nonsteroidal anti-inflammatory drug-induced cystitis in humans must be clarified by prospective clinical trials.

Endothelin receptor blockers reduce I/R-induced intestinal mucosal injury: role of blood flow

The aim of the present study was to assess the role of endothelin (ET) in ischemia-reperfusion (I/R)-induced mucosal injury. Mucosal permeability ((51)Cr-EDTA clearance) and tissue myeloperoxidase (MPO) activity were significantly increased after 30 min of ischemia followed by 30 min of reperfusion. The I/R-induced increases in mucosal permeability and polymorphonuclear leukocyte (PMN) infiltration were significantly attenuated by pretreatments with ET(A) (BQ-485) and/or ET(B) (BQ-788) receptor antagonists. Monoclonal antibody (MAb) directed against intercellular adhesion molecule-1 (ICAM-1; MAb 1A29) and superoxide dismutase (SOD) pretreatments significantly attenuated the increased mucosal permeability and PMN infiltration in a similar manner as with ET receptor antagonists. Superior mesenteric artery blood flow was significantly reduced during the reperfusion period. Both ET receptor antagonists caused a significant rise in blood flow compared with an untreated I/R group. In conclusion, our data suggest that ET(A) and/or ET(B) receptors, ICAM-1, and superoxide play an important role in I/R-induced mucosal dysfunction and PMN infiltration. Furthermore, ET is involved in the pathogenesis of post-reperfusion-induced damage and beneficial effects of ET receptor antagonism are related to an improvement of disturbed blood flow during the reperfusion period.

Estrogens ameliorate remote organ inflammation induced by burn injury in rats

OBJECTIVE AND DESIGN

The present study was designed to investigate the role of sex steroids in burn-induced remote organ injury.

MATERIAL OR SUBJECTS

Male Wistar albino rats were given burn trauma (n=39), and underwent castration or sham operation at 2 h following the burn injury.

TREATMENT

Rats were injected sc with either 17beta estradiol benzoate (E2, 10 mg/kg) or an androgen receptor blocker cyproterone acetate (CPA, 25 mg/kg) or vehicle, immediately after burn and at 12 h.

METHODS

At 24 h of burn insult, rats were decapitated. Blood samples for RIA of testosterone, estradiol and tumor necrosis factor (TNF)-alpha and the tissue samples for myeloperoxidase activitiy (MPO) were taken. ANOVA student's t test was used for statistical analysis.

RESULTS

Castration, antiandrogen and E2 treatments increased plasma estradiol levels and depressed burn-induced elevation in serum TNF-alpha levels. In the liver and lung, burn-induced increase in MPO was reduced by E2 and castration, while CPA was effective in reducing neutrophil infiltration only in the liver.

CONCLUSION

We propose that treatment with estrogens or antiandrogens might be applicable in clinical situations to ameliorate systemic inflammation induced by burn.

Morphological examination of the effects of defibrotide on experimentally induced bladder injury and its relation to interstitial cystitis

This morphological study aims to investigate the effects of defibrotide, a deoxyribonucleic acid derivative drug with cytoprotective, immunosuppressive and vasorelaxant effects, on protamine sulfate induced bladder injury. Wistar albino female rats were catheterized and intravesically infused with phosphate buffered solution (control group) or, either protamine sulfate (bladder injury group) or protamine sulfate+defibrotide (bladder injury+defibrotide group) dissolved in phosphate buffered solution. The morphology of the urinary bladder was investigated using light and electron microscopy. The number of mast cells in the mucosa, mucosal alterations, intercellular junctions, surface topography and the glycosaminoglycan (GAG) layer as well as microvillus formation on the luminal surface were evaluated. In the bladder injury group, ulcerated areas, irregularity of the GAG layer, increased number of mast cells, vacuole formation, dilated perinuclear cistern, formation of pleomorphic and uniform microvilli and dilatations in the intercellular spaces in the urothelium were observed. In the bladder injury+defibrotide group a relatively normal urothelial topography, GAG layer and a few mast cells in the mucosa, some dilatations between the intercellular areas, less uniform microvilli, regular perinuclear cistern and tight junctions were observed. These results show that defibrotide can inhibit PS induced bladder damage.

Early histological changes of ileal mucosa after augmentation cystoplasty

Segments of bowel are used routinely for transplantation in various pathological conditions such as contracted bladders or poorly compliant neuropathic bladders. However, little is known how these intestinal segments adopt to a toxic environment caused by urine. Therefore, the present study was performed to determine early histological changes of ileal mucosa after augmentation cystoplasty. Seven patients with augmentation cystoplasty underwent random cold-cup biopsies of ileal segments after a mean period of 14.4 months after cystoplasty and morphological changes were evaluated using light microscopy and transmission and scanning electron microscopy. Most pronounced features were varying degrees of villous atrophy, increased numbers of Paneth and goblet cells. Severity of atrophic villous changes were not related to the length of the interval between surgery and endoscopic biopsy. These findings may be explained as adaptations of bowel tissue to counteract noxious effects of urine and to maintain its epithelial function in the bladder.