摘要
目的观察不同月龄大鼠的糖代谢指标变化,了解在基础和糖刺激下增龄对大鼠胰岛β细胞功能的影响。方法以4月龄(青年组,n=15)、14月龄(中年组,n=15)和24月龄(老年组,n=15)健康雄性Wistar大鼠为研究对象,进行口服葡萄糖耐量试验(OGTT)和胰岛素释放试验(IRT),比较三组间基础血糖和胰岛素水平的差异,计算糖负荷后胰岛素增值与血糖增值的比值(ΔI10/ΔG10),120min葡萄糖、胰岛素曲线下面积(AUCg,AUCi),葡萄糖与胰岛素曲线下面积比值(AUCi/g),胰岛素抵抗指数(HOMA-IR),胰岛β细胞功能指数(HOMA-β)等,以分析各组间胰岛功能的差异。结果随着月龄的增长,空腹血糖有升高的趋势,但未达到统计学差异。OGTT后老年组大鼠表现为血糖达峰时间延长,血糖峰值增加,OGTT2h血糖及AUCg增加,即老年组大鼠出现糖耐量异常状态,主要表现为餐后高血糖。青年组、中年组和老年组大鼠空腹胰岛素水平分别为(0.59±0.14)、(1.60±0.15)、(2.37±0.04)μg/L(两两相比均P<0.01);IRT中,老年组大鼠胰岛素达峰时间延迟,ΔI10/ΔG10降低,AUCi增加(P<0.05)。使用稳态模型评估,HOMA-β在青年、中年和老年组中呈递增趋势,但未达到统计学差异;而HOMA-IR在青年、中年和老年组分别为3.09±0.80、8.34±0.72、13.14±1.59(两两相比均P<0.01)。结论正常老龄大鼠存在一定的胰岛素抵抗和代偿性胰岛素分泌增加,但由于胰岛素分泌的早期时相受损,仍然出现糖负荷后血糖增高状态。
Objective To evaluate the effect of aging on the function of islet beta-cell in the normal and post- stimulus condition. Methods Healthy male Wistar rats in 4-month-old（youth, n= 15）, in 14-month-old （middle age, n=15） and in 24-month-old （aged, n 15） were used in the present study. Oral glucose tolerance test（OGTT） and insulin releasing test（IRT） were performed to compare the difference of basic glucose and insulin among three groups, to calculate the areas under the curve of plasma glucose levels（AUCg） and plasma insulin levels（AUCi）, the ratio of areas under the curve of insulin and glucose（AUCi/g）, the ratio of profile in insulin and glucose on post-stimulus condition（△I10/△G10 ）, insulin resistance index（HOMA-IR） and the function index of islet beta-cell（HOMA-β）, and to essay the function of islet cells. Results Fasting glucose was increased with aging, without statistical signifi- cance in the different groups. The peak time of blood glucose was later, peak and 2h blood glucose were higher, the AUCg was increased in the old group than the other 2 groups. Fasting insulin was（0.59±0.14）, （1. 60±0.15） and （2.37±0.04）μg/L in three groups, with statistical significance between two of three groups（P〈0. 01）. In aged group, insulin releasing was mostly delayed, △I10/△G10 was the lowest and AUCi increased （P〈0.05）. H OMA-β was gradually increased in young, middle and aged groups, but without statistical significance. HOMA-IR was 3.09±0.80, 8.34±0.72 and 13.14±1.59（P〈0.01）. Conclusion Insulin resistance and compensative high level insulin secretion are observed in the normal old rats. The impaired rapid secretion of insulin and partly compensative higher insulin level might explain the impaired glucose tolerance in the elderly rats.
出处
《中华老年多器官疾病杂志》
2009年第2期166-169,共4页
Chinese Journal of Multiple Organ Diseases in the Elderly
基金
国家自然科学基金(30873412)
