Decreased mRNA Expression of Cystathionine Gamma lyase and H2S Concentration in Gastric Mucosal Tissue in Diabetic Rats

ABSTRACT Background and aim: It is well established that the rate of gastric lesions increases in diabetic rats. Recently, the protective effect of hydrogen sulfide (H2S) in gastric mucosa has been proven. This study aimed to determine the release of H2S and mRNA expression of cystathionine gamma lyase (CSE) in gastric mucosa in alloxan-diabetic rats in response to distention-induced gastric acid secretion. Twenty-four rats were randomly assigned to 4 groups (6 in each). They were the normal-control, distention-control, diabetic-control, and distention-diabetic groups. Under anesthesia, animals underwent a tracheotomy and midline laparotomy. To washout the gastric contents, a catheter was inserted in the stomach through the duodenum. To determine the effect of distention-induced gastric acid secretion on H2S release and mRNA expression of CSE, the stomachs were distended by normal saline. At the end of experiments, animals were sacrificed and the gastric mucosa was collected to determine H2S concentration and to quantify mRNA expression of CSE by quantitative real-time PCR. Mucosal release of H2S and mRNA expression of CSE significantly increased in response to stimulated gastric acid secretion in normal rats (P<0.01), while the increases in diabetic rats were not significant. Basal release of H2S and mRNA expression of CSE in gastric mucosa were significantly in diabetic rats lower than normal rats. On the basis of the results, we conclude that the decreased release of H2S in response to basal and stimulated gastric acid output in alloxan-diabetic rats compared to normal rats is largely due to downregulation of mRNA expression of CSE.

Lipoic acid and diabetes: Effect of dihydrolipoic acid administration in diabetic rats and rabbits.

Relative α-lipoic acid content of diabetic livers was considerably less than that of normal livers as determined by gas chromatography. It was not possible to detect any dihydrolipoic acid in the livers. Biochemical abnormalities such as hyperglycaemia, ketonemia, reduction in liver glycogen and impaired incorporation of [2-14C] -acetate into fatty acids in alloxan diabetic rats were brought to near normal levels by the oral or intraperitoneal administration of dihydrolipoic acid. The effect of α-lipoic acid was comparable to that of dihydrolipoic acid in reducing the blood sugar levels of diabetic rabbits during a glucose tolerance test. The results suggest that the mode of action of lipoic acid was through stimulation of pyruvate dehydrogenase.