JAK2/STAT5通路在胰岛对妊娠适应中的作用

Role of JAK2/STAT5 pathway in adaptation of pancreatic islets to pregnancy

目的探讨妊娠中晚期SD大鼠胰岛功能增强的机制。方法以妊娠15 d的SD大鼠(实验组,n=24)和同批次未妊娠的雌性SD大鼠(对照组,n=24)作为实验对象。通过原位灌注胰岛分离的方法获得单个胰岛,用胰酶消化胰岛,形成单个细胞,原代分离的胰岛加入含5.6 mmol/L葡萄糖和15%FBS的DMEM培养基终止消化,用含2.8 mmol/L葡萄糖(对照)或5.6 mmol/L葡萄糖的KRB缓冲液培养1 h,利用全细胞膜片钳记录B细胞膜电压依赖型钾通道(Kv)电流。采用Real-Time PCR技术测定胰岛JAK2/STAT5通路的关键分子催乳素受体(PRLR)、Janus蛋白酪氨酸激酶(JAK2)、信号转导和转录激活子5(STAT5A和STAT5B)、葡萄糖代谢的关键分子葡萄糖转运体2(GLUT2)、葡萄糖激酶(GK),以及胰岛素分泌相关的分子ATP敏感性钾通道(KATP)、电压依赖性钙通道(VDCC)mRNA的表达。结果在10～60 mV膜电压条件下,实验组大鼠在5.6 mmol/L葡萄糖刺激下,胰岛单个B细胞细胞膜Kv电流显著低于对照组,差异有统计学意义(P<0.05)。实验组大鼠胰岛组织PRLR、JAK2、STAT5A、STAT5B、GLUT2、VDCC、KATPmRNA的相对表达量上调,分别为对照组的2.50、1.84、1.54、2.45、1.41、1.68、1.55倍(P<0.05或P<0.01),两组大鼠胰岛组织GK mRNA的相对表达量比较差异无统计学意义(P>0.05)。结论妊娠中晚期SD大鼠胰岛功能增强可能与催乳素促进JAK2/STAT5通路、葡萄糖代谢及胰岛素分泌相关分子的表达有关,为糖尿病的治疗提供了新的思路。

Objective To explore the mechanism of enhanced pancreatic islet function in SD rats during middle to late pregnancy.Methods SD rats with pregnancy of 15 d were selected as experiment group（n=24）,and another 24 rats of the same batch without pregnancy were served as controls（n=24）.Single pancreatic islet was obtained by in situ perfusion and pancreatic islet isolation,pancreatic islet was digested by pancreatic enzyme,single cell was formed,isolated pancreatic islet was treated with DMEM culture medium containing 5.6 mmol/L glucose and 15% FBS.After culture with KRB buffer containing 2.8 mmol/L glucose（control） or 5.6 mmol/L glucose for 1 h,whole-cell patch-clamp was used to record pancreatic islet B cell membrane voltage-dependent potassium channel（Kv） current.Real-Time PCR was employed to detect the expression of prolactin receptor（PRLR）,Janus tyrosine kinase 2（JAK2）,signal transducer and activator of transcription 5（STAT5A and STAT5B）,glucose transporter-2（GLUT-2）,glucokinase（GK）,ATP-sensitive potassium channel（KATP） and voltage-dependent Ca2＋ channel（VDCC） mRNA.Results Under the condition of 10 mV to 60 mV membrane voltage,Kv current of pancreatic islet B cell membrane in experiment group stimulated by 5.6 mmol/L glucose was significantly lower than that in control group（P0.05）.The relative expression of PRLR,JAK2,STAT5A,STAT5B,GLUT2,VDCC and KATP mRNA in tissues of pancreatic islet in experiment group was up-regulated,and the values were 2.50,1.84,1.54,2.45,1.41,1.68 and 1.55 times of those in control group（P0.05 or P0.01）.There was no significant difference in the relative expression of GK mRNA in tissues of pancreatic islet between two groups（P0.05）.Conclusion Lactogenic hormones play a primary role in pancreatic islet function enhancement during middle to late pregnancy in SD rats,which may be involved in the up-regulation of JAK2/STAT5 pathway,glucose metabolism and expression of insulin secretion-related molecules.