Abstract
Insulin dependent diabetes mellitus (IDDM) results from irreversible loss of beta cells (beta-cells) of the pancreas. A Streptozotocin (STZ)-induced diabetes in animal model mimics, in some aspects, recent onset IDDM. This study was conducted to investigate the effect of nicotinamide on experimentally-induced IDDM. Thirty Spraque Dawley rats were divided into 3 groups; a control group, a diabetic group which received an intraperitoneal (i.p.) injection of 55 mg/kg STZ and a nicotinamide group (1g/kg/day) which were dosed orally for 3 days followed by (i.p.) STZ (55 mg/kg) with the nicotinamide treatment continuing for an additional 14 days. Rats receiving STZ became diabetic after 2 weeks. This diabetic group showed hyperglycemia, and a very low level of C-peptide. Furthermore, pancreatic islets exhibited increased nitric oxide (NO) production together with an increased apoptotic index (as detected by TUNEL and electron microscopy). Nicotinamide treatment prevented STZ-induced diabetes, it also antagonized an increase in NO, and inhibited beta-cell apoptosis. Fasting blood glucose, serum insulin and serum C-peptide were all within the normal range in the nicotinamide group. The nicotinamide protection of beta-cells may be facilitated via inhibition of apoptosis and nitric oxide generation. It is suggested that nicotinamide might be considered an effective agent for the prevention and treatment of IDDM in prediabetic, and early stages, of IDDM.