Objective: To investigate the correlation between visceral adipose tissue-derived serine protease inhibitor (vaspin) concentration and insulin sensitivity in the visceral adipose tissue of young obese Sprague-Dawley (SD) rats.
Methods: Twenty-four SD rats which had been weaned 3 weeks before were randomly divided into two groups (n=12 each) to receive a high-fat and normal diet. The weight and abdominal circumference (AC) of each rat were measured, the fasting plasma glucose (FPG) and fasting insulin (FINS) in blood from the angular vein were measured after 12 hours of fasting and blood glucose (BG) and insulin (INS) levels in blood from the angular vein were measured at 60 and 120 minutes after intraperitoneal injection of 50% glucose (2 g/kg). The rats were sacrificed, and their liver and visceral adipose tissue were weighed. The vaspin concentration of the visceral adipose tissue in each rat was measured using ELISA. Correlation analysis was performed on the vaspin concentration and other indices.
Results: Compared with the normal diet group, the high-fat diet group showed significantly higher weight, AC, weight of visceral adipose tissue, FPG, FINS, 120 minute INS level, vaspin concentration, homeostasis model assessment for insulin resistance (HOMA-IR) and homeostasis model assessment of β cell function (HOMA-β) (P<0.05) Insulin sensitivity index (ISI) was significantly lower (P<0.01). Vaspin concentration was positively correlated with visceral adipose tissue and liver weight, AC, 120 minute INS level, FPG, FINS, HOMA-IR and HOMA-β (P<0.05), and negatively correlated with ISI (P<0.05).
Conclusions: High expression of vaspin is associated with insulin resistance in young obese SD rats. Vaspin is presumably an adipocytokine that can increase insulin sensitivity, promote insulin secretion by islet β-cells and improve glucose tolerance, and it may be involved in insulin resistance and the disturbance of carbohydrate metabolism.