升糖速度对低血糖大鼠脑损伤影响机制初探

Influence of different glucose rising speed on hypoglycemic brain injury in rats

目的 研究及探讨不同升糖速度对低血糖性大鼠脑损伤影响的机制.方法 采用健康SD雄性大鼠36只,体重250～ 300 g,采用简单随机抽样分组的方式将其分为6组：空白组、假手术组和4个实验组,每组6只大鼠.空白组不作任何处理,假手术组胰岛素腹腔注射的同时静脉泵注葡萄糖并维持正常血糖,4组实验组在胰岛素诱导的低血糖后按照不同的泵注速度进行升糖,根据1h后血糖的不同水平分为＞ 1.0 ～ 3.0 mmoL/L组、＞3.0 ～6.0 mmoL/L组、＞6.0 ～9.0 mmol/L组和＞9.0 mmol/L组.采用Western blotting法检测不同组之间抗凋亡基因Bax及Bcl-2蛋白在大脑皮层及海马神经细胞上表达,采用流式细胞仪检测不同组之间大脑海马及皮层神经细胞内Ca^2＋的浓度.各组间计量资料比较采用单因素方差分析.结果 Bax/Bcl-2比值：相对于空白组,假手术组、4个实验组大脑皮层及海马的Bax/Bcl-2比值有显著性的提高,差异有统计学意义（F=265.8、42.7,均P＜0.05）,其中＞9.0 mmol/L组Bax/Bcl-2最大,＞1.0～3.0 mmol/L组次之,与＞3.0～ 6.0 mmol/L组、＞6.0 ～9.0 mmol/L组之间差异有统计学意义（F=212.1、27.4,均P＜0.05）.钙离子浓度：相对于空白组,假手术组和4个实验组的钙离子浓度显著性的提高,差异有统计学意义（F=79.8、355.0,均P＜0.05）,其中＞9.0 mmol/L组钙离子浓度最大,＞1.0～ 3.0 mmol/L组次之,与3.0 ～6.0 mmol/L组、＞6.0 ～ 9.0 mmol/L组之间差异有统计学意义（F=50.1、71.1,均P＜0.05）.结论 过慢、过快的升糖速度都不利于低血糖性脑损伤的恢复.

Objective To explore the mechanism of the effect of different glucose rising speed on hypoglycemic brain injury in rats.Methods A total of 36 male SD rats （weight：250-300 g） were divided into 6 groups with simple random sample：the blank group,sham group and 4 experimental groups,6 rats in each group.The blank group was subjected to no disposal,the sham group was given femoral vein infusion of glucose and intraperitoneal injection of insulin to maintain normal blood glucose.The experimental groups were given femoral vein infusion of glucose with different speed after hypoglycemia induced by insulin injection.According to the glucose concentration after 1 hour of vein glucose infusion,the experimental groups were further divided into 4 groups （〉 1.0-3.0,〉3.0-6.0,〉6.0-9.0 and 〉9.0 mmol/L group）.Western blotting was used to detect the protein expression levels of gene Bax and Bcl-2.Flow cytometry was used to detect the Ca2＋ concentration in the neurocyte in hippocampus and cerebral cortex of the different groups.Comparison of measurement data among groups was done by using one-way analysis of variance.Results Ratio of Bax to Bcl-2：compared with those in blank group and sham group,Bax/Bcl-2 in cerebral cortex and hippocampus in 4 experimental groups increased significantly （F =265.8,42.7,both P〈0.05）,〉9.0 mmol/L group had the highest Bax/Bcl-2,〉 1.0-3.0 mmol/L group had the second highest.There was significant differences in Bax/Bcl-2 among the 4 experimental groups （F =212.1,27.4,both P 〈 0.05）.Ca^2＋ concentration：compared with those in the blank group and sham group,the Ca^2＋ concentration in cerebral cortex and hippocampus in 4 experimental groups increased significantly （F =79.8,355.0,both P 〈0.05）.〉9.0 mmol/L group had the highest and 〉 1.0-3.0 mmol/L group had the second highest level of Ca^2 ＋ concentration.There was significant differences in Ca^2 ＋ concentration among the 4 experimental groups （F =50.1,71.1,both P 〈 0.05）.Conclusion Both too fast and too slow glucose rising speed will aggravate the hypoglycemic brain injury.