STZ诱导的糖尿病大鼠早期胃排空与血浆ghrelin和obestatin的关系

Relationships between gastric emptying and plasma ghrelin and obestatin levels in the early stages of streptozotocin-induced diabetic rats

目的研究STZ诱导的糖尿病大鼠早期胃排空的变化以及与血浆胃生长素(ghrelin)和肥胖抑制素(obesta-tin)之间的关系。方法40只Wistar大鼠随机分为正常对照组(NC组)、糖尿病组(DM组)、低剂量胰岛素组(LD组)、高剂量胰岛素组(HD组)。利用链脲佐菌素(STZ)制备糖尿病大鼠模型,LD组和HD组分别每天给以中性人胰岛素4U和8U皮下注射,于注射STZ后2周测定胃排空及血浆ghrelin和obestatin水平。结果注射STZ2周后,DM组大鼠血糖和血浆ghrelin水平明显高于其他3组(P<0.01),HD组大鼠血糖虽仍明显高于NC组(P<0.01),但两组血浆ghrelin水平没有明显差别(P>0.05)。DM组、LD组和HD组大鼠血浆obestatin水平均明显高于NC组(P<0.01),但3组之间没有明显差别(P>0.05);DM组大鼠胃排空明显快于其它3组(P<0.01),HD组大鼠胃排空虽明显低于DM组和LD组(P<0.01),仍快于NC组(P<0.01)。结论STZ诱导的糖尿病大鼠早期胃排空明显加快,内源性ghrelin的增加可能在其中起重要作用,内源性obestatin在其中的作用有待进一步探讨。

Objective To investigate gastric emptying and plasma ghrelin and obestatin levels in the early stages of streptozotocin-induced diabetic rats,and to explore the relationship between them.Methods Forty Wistar rats were randomly divided into four groups：the normal control group（NC group）,the diabetes mellitus group（DM group）,the low-dose insulin-treated group（LD group） and the high-dose insulin-treated group（HD group）.Rats were made diabetic by intraperitoneal injection of streptozotocin（STZ）.Each rat in the LD group and HD group received 4 U and 8 U Humulin NPH by subcutaneous injection every day respectively.Two weeks after the STZ injection,gastric emptying,plasma ghrelin levels and obestatin levels were determined.Results Two weeks after the STZ injection,blood glucose levels and plasma ghrelin levels increased significantly in the DM group compared with those in the other three groups（P〈0.01）.Although the blood glucose levels still increased significantly in the HD group compared with those in the NC group（P〈0.01）,the plasma ghrelin levels had no statistical difference between the two groups（P〉0.05）.The plasma obestatin levels increased significantly in the DM,LD and HD groups compared with those in the NC group（P〈0.01）,but those in the other three groups had no statistical differences（P〉0.05）.Gastric emptying accelerated significantly in the DM group compared with those in the other three groups（P〈0.01）.Although gastric emptying slowed significantly in the HD group compared with those in the DM and LD groups（P〈0.01）,it accelerated significantly compared with that in the NC group（P〈0.01）.Conclusion This study suggests that gastric emptying signifi-cantly accelerated during the early stages of streptozotocin-induced diabetic rats.Elevated endogenous ghrelin may play an important role in it and the role of endogenous obestatin needs further study.