+G_Z暴露下高胆固醇兔胆囊排空功能、胆囊收缩素及生长抑素的变化

Effects of +G_z exposure on gallbladder emptying function,cholecystokinin,and somatostatin in rabbits with high cholesterol diets

目的探讨+GZ暴露下胆囊排空功能及胆囊收缩素(CCK)、生长抑素(SS)的变化,探讨其在胆囊结石形成过程中的作用。方法雄性新西兰纯种兔24只,随机分成高胆固醇饮食组(对照组,n=8)及高胆固醇饮食加+GZ暴露组,后者按暴露时间又分为+GZ暴露4周组和+GZ暴露6周组(n=8)。于第4、6周实验结束时,采用放射免疫法测定胆囊CCK和SS含量;计算胆囊体积及最大排空率;采用微电脑生理压力记录仪记录胆囊内压;计量胆囊容量;肉眼观察胆汁性状及有无结石形成,偏振光显微镜观察胆囊壁胆固醇结晶情况。结果 +GZ暴露4周、6周组胆囊容积增大,表现为最大排空率(E%)降低,空腹体积(BV)和残存体积(RV)增大,胆囊压力增加(P<0.05);+GZ暴露4周、6周组胆囊CCK含量均明显低于对照组,且随着+GZ暴露时间增加,CCK含量逐渐降低(P<0.05);+GZ暴露4周、6周组胆囊SS含量均高于对照组,且随着+GZ暴露时间增加,SS含量逐渐升高(P<0.05)。+GZ暴露4周、6周后,胆汁混浊,黏稠,可见胆固醇结晶,但无肉眼可见结石。结论 +GZ暴露可引起高胆固醇饮食兔胆囊排空功能异常,也可使胆囊黏膜CCK含量降低、SS含量升高,导致胆汁淤滞,为胆囊胆固醇结石的形成提供了条件。

Objective The present study explores the effects of ＋Gz exposure on the gallbladder emptying function,cholecystokinin（CCK）,and somatostatin（SS） in rabbits with high cholesterol diets and investigates its mechanism in the occurrence of cholecystolithiasis.Methods Twenty-four male New Zealand rabbits were randomly divided into the high cholesterol diet（control group,n=8） and high cholesterol diet plus ＋Gz exposure groups.The latter was divided into the four-and six-week ＋Gz exposure groups（n=8） based on the exposure time.Radioimmunoassay was used to determine the CCK and SS contents of the gallbladder at the end of the experiment in the fourth and sixth weeks and to calculate the gallbladder volume and maximum emptying ratio.A microcomputer biodynamic pressure monitor was used to record the hydrostatic pressure in the gallbladder to measure its capacity.Moreover,the bile properties and formation of concretion were observed with the naked eye,and polarized light microscopy was used to observe cholesterin crystallization on the gallbladder wall.Results The gallbladder capacity increased upon ＋Gz exposure for four and six weeks,indicating that the maximum emptying ratio（E%） decreased,the empty and residual volumes improved,and the pressure increased（P0.05）.After ＋Gz exposure for four and six weeks,the CCK contents in the experimental groups were evidently lower than that in the control group and gradually decreased（P0.05） as the ＋Gz exposure time increased.On the other hand,after ＋Gz exposure for four and six weeks,the SS contents in the experimental groups were higher than that in the control group and gradually improved（P0.05） as the ＋Gz exposure time increased.After ＋Gz exposure for four and six weeks,bile was turbid and sticky with cholesterol crystals and without visible concretion.Conclusions Therefore,＋Gz exposure may cause abnormal gallbladder emptying functions,decrease CCK content,increase SS content,and thus cause bile stasis.These results indicate that ＋Gz exposure provides the prerequisites for the occurrence of cholecystolithiasis.