HGF/C-MET PATHWAY HAS A ROLE IN TESTICULAR DAMAGE IN DIABETES INDUCED BY STREPTOZOTOCIN.

OBJECTIVE: The aim of the study was to investigate the role of Hepatocyte Growth Factor (HGF)/c-Met pathway in testicular damage provoked by streptozotocin (STZ)- induced diabetes and the effects of insulin treatment on the HGF/c-Met pathway. METHODS: Total 21 paraffin-embedded testicular tissues of control (n=7), streptozotocin (STZ)-induced diabetic (n=7) and insulin-treated diabetic (n=7) Wistar albino rats were used in this study. Testicular damage was examined histologically and by Johnsen's score was also evaluated. Immunohistochemical stainings of HGF and c-Met were analysed by using antibodies against HGF and c-Met. RESULTS: We found the degeneration in seminiferous tubule epithelium and disorganization of spermatogenetic cell series in testis tissues of diabetic rats. We also determined decrease both in seminiferous tubule diameter and Johnsen's scores in diabetic group. The expressions of HGF and c-Met in seminiferous tubule epithelium and in spermatogenic cells (especially spermatocytes and spermatids) were significantly increased in diabetic rats compared to those of control. Insulin treatment significantly reduced the diabetes-induced morphological changes and HGF/c-Met over expressions in the diabetic rat testis. CONCLUSION: HGF/c-Met pathway might have a role in diabetes- induced testicular damage. Drugs acting on this pathway might be effective to prevent or delay the testicular damage induced by diabetes.

Effect of melatonin on testicular damage in streptozotocin-induced diabetes rats.

BACKGROUND: It is well known that diabetes mellitus is associated with impairment of testicular function. In the present study, we aimed to demonstrate the effect of melatonin on testicular damage in male rats with streptozotocin (STZ)-induced diabetes. METHODS: Male Wistar rats were divided into 4 groups: (1) control group, (2) melatonin-treated nondiabetic group, (3) diabetic group and (4) melatonin-treated diabetic group. Diabetes was induced by STZ injection. Melatonin was administered intraperitoneally at the dose of 10 mg/kg for 5 days. Testicular damage was examined by using hematoxylin and eosin staining and periodic acid-Schiff staining, and apoptosis was determined by terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL). Potential disorders associated with seminiferous tubular sperm formation were evaluated using the Johnsen score. RESULTS: Diabetic rats showed a reduction in seminiferous tubule diameter, increased thickening of the basement membrane in seminiferous tubules and degenerated germ cells. TUNEL-positive cells were significantly more numerous in diabetic rats than in control rats. Melatonin significantly attenuated the diabetes-induced morphological changes and germ cell apoptosis in the diabetic rat testis. The number of polymorphonuclear leukocytes was significantly decreased in group 4 when compared to group 3. CONCLUSIONS: These results suggest that intraperitoneal administration of melatonin for 5 days is a potentially beneficial agent to reduce testicular damage in adult diabetic rats, probably by decreasing oxidative stress.

Short-term melatonin treatment improved diabetic nephropathy but did not affect hemorheological changes in diabetic rats.

Increased oxidative stress and hemorheological disturbances may play very important roles in the development of microangiopathies in diabetes mellitus. This study was designed to determine the healing effect of melatonin on hemorheological parameters and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. Wistar male rats were divided into four groups as control, untreated-diabetic, melatonin-treated control and melatonin-treated diabetic rats. Diabetes was induced by injecting streptozotocin (45 mg/kg, i.p.). Fourteen weeks after inducement of diabetes, melatonin (10 mg/kg) was administered intraperitoneally for 5 days to the rats. Erythrocyte deformability and aggregation were measured by laser differaction analysis (LORCA). Diabetic nephropathy was assessed by histopathologic evaluation and TUNEL stain in the diabetic kidney. Decreased erythrocyte deformability and increased erythrocyte aggregation indices were determined in the diabetic group. Melatonin treatment did not improve these hemorheological abnormalities. However, renal injuries were diminished in the melatonin-treated diabetic group compared to the untreated diabetic group. Also, melatonin had an antiapoptotic effect on the diabetic kidney. It was concluded that i.p. administration of melatonin for 5 days improved renal injury in diabetic rats, probably by decreasing oxidative stress, but did not affect hemorheological changes.

Effects of subchronic parathion exposure on cyclosporine pharmacokinetics in rats.

Parathion undergoes enzymatic oxidation by hepatic cytochrome P-450 (CYP450) enzymes to the active metabolite paraoxon. Consequently, alterations in CYP450-dependent oxidation may affect the pharmacokinetics and pharmacodynamics of drugs that are metabolized in the liver. The CYP3A family is known to be responsible for the majority of cyclosporine metabolism. The aim of the present study was to assess the disposition kinetics of cyclosporine during subchronic parathion exposure. Male Wistar rats were administered either water or two different doses of parathion (1/100 LD50, 1/25 LD50; LD50 = 14 mg/kg) by gavage for 6 wk. Subsequently, rats in each experimental group received a single oral dose of cyclosporine (10 mg/kg), and serial blood samples were drawn from the carotid artery over a period of 48 h. Pharmacokinetic analysis showed that parathion increased the blood cyclosporine concentration twofold as evidenced by AUC (area under the curve), half life (t 1/2) and peak plasma concentration (Cmax). This may be due to inhibition of cyclosporine metabolism, an interaction that may be of clinical relevance in immunosuppression therapy.

Pharmacological analysis of 5-hydroxytryptamine effects on human isolated ureter.

5-Hydroxytryptamine (5-HT) induced concentration-dependent contractions in human isolated ureteral strips in vivo. On the basis of available selective 5-HT agonists and antagonists, we have further investigated the receptors involved. At concentrations from 10 n m to 1 m m, 5-HT induced concentration-dependent contractions. Significant contractions were not observed with 5-HT1Aagonist 8-OH-DPAT (10(-9)-10(-4)m), 5-HT1Dalphaagonist sumatriptan (10(-9)-10(-4)m), 5-HT2agonist DOI (10(-9)-10(-4)m), 5-HT3agonist 2-methyl 5-HT (10(-9)-10(-3)m) and 5-HT4agonist renzapride (10(-9)-10(-3)m) on the human isolated ureter. On the other side, a 5-HT1-likeagonist 5-CT (10(-9)-10(-3)m) produced contractions on the isolated samples. The Emaxdeveloped by 5-CT was significantly smaller than that of the 5-HT (29% of 5-HT). Methithepin, the less selective 5-HT1/2antagonist (10(-9)-10(-6)m), 5-HT3antagonist, ondansetron (10(-9)-10(-5)m) and 5-HT4antagonist DAU 6285 (10(-8)-10(-6)m) did not antagonise the contractile responses to 5-HT. 10(-7)m ketanserin antagonised 5-HT induced contractile responses in ureteral strips. Additionally, combined administration of 5-HT4antagonist DAU 6285 (10(-6)m) and 5-HT1/2antagonist methithepin (10(-6)m) caused a rightward shift of the CRC of 5-HT yielding pEC50values of 4.68+/-0.15. 5-HT-induced contractile responses that were not abolished by TTX and atropine, thus supporting the suggestion that in the human, the contractile responses to cumulative addition of 5-HT of the ureter are not mediated by excitation of cholinergic neurons. In the present study the receptor mediating the contractile response to 5-HT in the human upper ureter could not be clearly designated 5-HT1-like, 5-HT2, 5-HT3or 5-HT4. This study suggests that contractile response to 5-HT in the upper segments of the human ureter appear to be mediated by an atypical 5-HT receptor subtype.

Acute renal failure following latrodectism.

Latrodectism is considered dangerous for human beings. Acute renal failure after envenomation is not common and usually results from prerenal failure. We report a 59-y-o man with acute oliguric renal failure due to a combination of prerenal and renal causes after being bitten by a black Latrodectus spider. He had the characteristic anxiety, severe hypertension, tremor, facial edema, and generalized diaphoresis. The patient recovered within a week without sequelae. Clinicians should not overlook the possibility of acute renal failure in latrodectism.

Circadian rhythmicity in serotonin-induced acute gastric mucosal injury in rats.

Time-dependent patterns in the susceptibility of the rat gastric mucosa to ulcerogenic stimuli involving stress or chemical injury have been described. The purpose of this study was to evaluate whether serotonin (5-HT)-induced gastric mucosal injury is produced in a circadian fashion in the rat model. In fasted Wistar rats (adapted for 3 weeks to a standard 12-h light-dark cycle), 5-HT administered subcutaneously (20 mg/kg, 4 h before autopsy) produced gastric mucosal injury. The stomachs were removed and the ulcers were scored for intensity, using a scale of 0-4. In studies performed at 4-h intervals, beginning 1 h after lights-on, most of the mucosal injury occurred at 2000 h, i.e. early in the dark phase. Likewise, serum corticosterone levels were also found to be high at the same time period. The time of 2000 h is approximately determined to be the beginning of the rats' active period. These results suggest that the extent of acute 5-HT-induced gastric mucosal injury varies with the time of day and that elevations in corticosterone concentrations might be responsible for the 5-HT-induced gastric mucosal injury.