下丘脑性厌食大鼠胃肠组织核组蛋白2／nesfatin-1的表达及胃排空的变化

Expression of gastrointestinal nucleobindin 2/nesfatin-1 and the changes of gastric emptying in anorectic rats caused by hypothalamic lesions

目的研究下丘脑性厌食大鼠和对照大鼠胃肠组织核组蛋白2／nesfatin-1的表达差异及胃排空变化情况。方法 雄性Wistar大鼠均分为下丘脑腹外侧核（VLH）损毁组和对照组，每组各6只，将电极插至大鼠VLH区，VLH损毁组通人2 mA直流电流10s损毁核团，对照组不通入电流。监测大鼠术后每日摄食量及体质量增加量，术后21 d，酚红灌胃法测定胃排空率，取胃、十二指肠、小肠、结肠组织，分别采用实时荧光定量RT-PCR及免疫组织化学和免疫荧光的方法检测核组蛋白2 mRNA及核组蛋白2／nesfatin-1蛋白的表达情况。计量资料采用两独立样本均数t检验，采用rest2009软件分析RT-PCR结果。结果VLH损毁组大鼠较对照组摄食量明显减少，体质量增长减慢，呈下丘脑性厌食表现。VLH损毁组大鼠胃排空率[（29．12±3．96）％]低于对照组[（61．08±6．02）％]，差异有统计学意义（=-10．864，P〈0．01）。核组蛋白2／nesfatin-l蛋白分别表达于大鼠胃黏膜中下2／3的内分泌细胞、十二指肠及小肠腺窝部潘氏细胞。VLH损毁组大鼠胃、十二指肠、小肠组织核组蛋白2／nesfatin1蛋白表达量均少于对照组，差异有统计学意义（t=-7．130，P=0．001；t=-9．599，P〈0．01；t=-21．111，P＜0．01）。VLH损毁组大鼠胃、十二指肠、小肠组织核组蛋白2 mRNA表达量分别为对照组的27．1％（16．5％～40．2％）、27．8％（13．6％～58．0％）、53．4％（41．0％～74．7％），差异均有统计学意义（t=-6．023，P〈0．01；t=-3．410，P=0．017；t=-4．900，P=0．001）；VLH损毁组结肠组织核组蛋白2 mRNA表达量为对照组的95．0％（74．0％～134．7％），差异无统计学意义（P〉O．05）。结论下丘脑性厌食大鼠胃、十二指肠、小肠组织核组蛋白2mRNA及核组蛋白2／nesfatin-1蛋白表达下调，胃排空率降低。

Objective To investigate the differences of the expression of nucleobindin 2/nesfatin-1in gastrointestinal tissues and the changes of gastric emptying between anorectic rats caused byhypothalamic lesions and the normal rats. Methods Male Wistar rats were evenly divided into theventrolateral hypothalamic nucleus （VLH） injured group and the control group, six rats in each group.The electrodes were put into VLH area of the rats, 2 mA direct current stimulated for 10 seconds to injurethe nucleus in VLH injured group and no current stimulated in control group. Daily food intake and theincreasing of the body weight of the rats were monitored after the operation. At 21 days after operation,gastric emptying rate was assessed by phenol red gavage method. The tissues of stomach, duodenum,small intestine and colon were obtained, and the expression of nucleobindin 2 at mRNA level andnucleobindin 2/nesfatin-1 protein was detected by real-time reverse transcription polymerase chain reaction（RT-PCR）, immunohistochemical method and immunofluorescent staining. Two independent samples t- test was performed for measurement data analysis, and the results of RT-PCR were analyzed by rest 2009 software. Results Compared with control group, the food intake of VLH injured group was less and weights increased slower, which appeared like hypothalamic anorexia. The gastric emptying rate of VLH injured group （（29. 12±3. 96）0/oo） was lower than that of control group （（61.08±6.02）%）, and the difference was statistically significant （t = -10. 864, P〈 0. 01 ）. Nueleobindin 2/nesfatin-1 protein was expressed in the endocrine cells in the lower 2/3 of gastric mucosa, paneth cells in the duodenum and the small intestine. The expressions of nucleobindin 2/nesfatin-1 protein in gastric, duodenal and small intestinal tissues of VLH injured group were less than those of control group, and the differences were statistically significant （t= -7. 130,P=0. 001;t = - 9. 599, P〈0.01.t= - 21. 111, P〈0.01）. The expressions of nucleobindin 2 at mRNA level of VLH injured group in stomach, duodenum, and small intestine were 27.1% （16.5% to 40.2%）, 27.8% （13.6% to 58.0%） and 53.4% （41.0% to 74.7%） of those of control group, and the differences were statistically significant （t =- 6. 023, P〈0.01%.t = -3.410,P=0.017%t=-4.900,P=0.001）. However, the expression of nucleobindin2 at mRNAlevel in colonic tissue of VLH injured group was 95.0% （74. 0% to 134.7%） of that of control group, and the difference was not statistically significant （P〉O. 05）. Conclusion The expression of nucleobindin 2 at mRNA level and nucleobindin 2/nesfatin-1 protein is down-regulated in gastric, duodenal and small intestinal tissues of anorectic rats caused by hypothalamic lesions, and the gastric emptying also reduces.