BACKGROUND: Insulin treatment plays a key role in management of diabetes mellitus. Clinical researches showed that extra improvements in restoration of insulin secretion of pancreatic beta cells were found in patients with newly diagnosed type 2 diabetes. The purpose of this study was to investigate the effects of early insulin treatment on insulin mRNA expression and morphological alterations of beta cells in a Sprague Dawley (SD) rat model of type 2 diabetes. METHODS: A rat model of type 2 diabetes mellitus (T2DM) was induced by a high fat diet (high energy, HE) and low doses of streptozotoxin (STZ, 40 mg/kg). A group of diabetic rats was then injected with protamine zinc insulin [PZI, 1 - 2 U x kg(-1) x d(-1)] for one week. Insulin mRNA expression, morphological features of pancreatic islets, and metabolic parameters were examined in rats using reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and other techniques. RESULTS: In insulin-treated diabetic rats, insulin mRNA levels prominently increased by 81.3% (P < 0.05), as compared with untreated diabetic rats. Moreover, timely insulin treatment noticeably improved the insulin content of beta cells, with an increase of 10.2% (P < 0.05), despite a slight reduction in fasting blood glucose (FBG), triglyceride (TG), and free fatty acid (FFA) levels, as compared to an untreated diabetic group. CONCLUSION: Insulin treatment at the onset of T2DM effectively improves insulin synthesis, as confirmed by morphological changes to beta cells in a rat model of type 2 diabetes.
BACKGROUND:Insulin treatment plays a key role in management of diabetes mellitus. Clinical researches showed that extra improvements in restoration of insulin secretion of pancreatic beta cells were found in patients with newly diagnosed type 2 diabetes. The purpose of this study was to investigate the effects of early insulin treatment on insulin mRNA expression and morphological alterations of beta cells in a Sprague Dawley (SD) rat model of type 2 diabetes. METHODS: A rat model of type 2 diabetes mellitus (T2DM) was induced by a high fat diet (high energy, HE) and low doses of streptozotoxin (STZ, 40 mg/kg). A group of diabeticrats was then injected with protamine zinc insulin [PZI, 1 - 2 U x kg(-1) x d(-1)] for one week. Insulin mRNA expression, morphological features of pancreatic islets, and metabolic parameters were examined in rats using reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and other techniques. RESULTS: In insulin-treated diabeticrats, insulin mRNA levels prominently increased by 81.3% (P < 0.05), as compared with untreated diabeticrats. Moreover, timely insulin treatment noticeably improved the insulin content of beta cells, with an increase of 10.2% (P < 0.05), despite a slight reduction in fasting blood glucose (FBG), triglyceride (TG), and free fatty acid (FFA) levels, as compared to an untreated diabetic group. CONCLUSION:Insulin treatment at the onset of T2DM effectively improves insulin synthesis, as confirmed by morphological changes to beta cells in a rat model of type 2 diabetes.