The intestinal calcium absorption inhibition in diabetes mellitus occurs with alteration in the antioxidant system

RODRÍGUEZ V. A; PERALTA LÓPEZ M.E; RIVOIRA M.A; TOLOSA DE TALAMONI N. G

Bs As

Congreso; AAOMM; 2012

Previous studies of our laboratory demonstrated that duodenal oxidative stress is associated with a reduction of intestinal calcium absorption. The aim of this work was to analyze the duodenal antioxidant system in an experimental model of DM. Two month old male Wistar rats were divided into two groups: a) controls and b) treated with streptozotocin (single intraperitoneal injection of 60 mg/kg body weight in 100 mM citrate buffer pH 4.5) after a 12-hour fast. Glucose in serum and urine was determined before the induction as well as after 5 days, 1 and 2 months. Rats with glycemia over 250 mg/dl were considered diabetic. Calcium, phosphorus and glycosilated hemoglobin were measured. Total glutathione (GSH), the activity of alkaline phosphatase (AP) and antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were determined in duodenal mucosa by spectrophotometry. Controls and diabetic rats had similar levels of calcium and phosphorus in serum. AP activity was significantly lower in diabetic rats than in 5 days and 1 month controls after the induction while it was higher 2 months after streptozotocin injection. Total GSH content decreased in diabetic rats as compared with controls at the studied times. SOD activity did not change whereas CAT activity increased in diabetic rats5 days and 1 month after induction, reaching the control values 2 months postinduction. In conclusion, the alteration in duodenal antioxidant system, evidenced by a decrease in GSH and increase in the CAT activity, could impact on calcium absorption and thus contribute to bone demineralization.