The effect of calorie restriction at early age on their islet β cell mass in adulthood of rats / 中华老年医学杂志

ABSTRACT

Objective To study the effect of calorie restriction at early age of rats on their islet β cell mass in adulthood.Methods Sixteen 8-week-old male SD rats were randomized to control group (n=7) and calorie restricted group (n =9).The rats in control group took food freely,while the ones in calorie restricted group were given 70％ calorie of the control group.After 24 week calorie restriction,cholesterol (TC),triglyceride (TG),high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) were tested.The β cell mass was measured by immunohistochefistry and the activity of superoxide dismutase (SOD) as well as the level of malondialdehyde (MDA) in pancreas homogenate were determined by ELISA.Results The increase of the body weights(45 g vs.184 g)and the level of TG [(0.61±0.15)mmol/L vs.(0.78±0.14)mmol/ L]of the rats in the calorie restricted group were lower than those of the control group (P＜0.05),while the β cell mass [(43.6±9.8)mg vs.(31.9± 11.6)mg],β cell mass of every milligram pancreas tissue[(89.7 ± 7.4) μg/mg vs.(44.8g ± 14.1) μg/mg] and β cell mass per body weight[(11.5±2.5) × 10-5 vs.(6.3 ±2.3) × 10-5]of the rats in the calorie restricted group were higher than those of the control group (P＜0.05).There were no differences in the SOD activity [(0.91±0.30)nmol/ mg protein vs.(0.68±0.14)nmol/ mg protein]and MDA level [4.97± 0.65)U /mg protein vs.(6.05 ±2.14)U/mg protein] in pancreas homogenate between the two groups (P＞0.05).Conclusions Calorie restriction at early age of rats may increase the islet β cell mass in their adulthood.