快速进入高海拔地区对大鼠小肠电活动及小肠Cajal间质细胞微观结构和功能的影响

Effects of ascending to high altitude on small intestine electrical activity,ultrastructure and function of interstitial cells of Cajal in the rats

目的快速进入高原后,不同海拔高度及时间点下大鼠小肠电活动变化及其对小肠Cajal间质细胞(interstitial cells of Cajal,ICC)微观结构和功能的影响。方法 130只SD雄性大鼠随机分为低海拔地区组(A组,海拔400 m)、中度海拔地区组(B组,海拔2 260 m)和高海拔地区组(C组,海拔4 300 m),B、C组又以进入高原地区后的时间划分为1 d、3 d、5 d、7 d、10 d和14 d组,每组10只大鼠。测定各组大鼠空肠电活动数据,并应用免疫荧光染色及电子显微镜观察小肠ICC的功能及微观结构变化。结果大鼠小肠电波幅及波频在中度海拔地区5 d组及高海拔地区3 d组行到最低点(P<0.05),且高海拔地区3 d组受损伤更加明显(P<0.05)。小肠ICC的功能及微观结构也可同步观察到类似改变,于中度海拔地区5 d组及高海拔地区3 d组受损伤最明显,电镜下可观察到ICC的缝隙连接减少、细胞器减少并出现凋亡小体等,并以高海拔地区3 d组最显著。用c-kit免疫荧光标记同部位ICC,也可观察到中度海拔地区5 d组及高海拔地区3 d组免疫荧光强度最低(P<0.05),且高海拔地区3 d组降低更显著(P<0.05)。结论快速进入高原对于大鼠小肠电活动影响显著,且海拔高度越高大鼠小肠电活动受损越严重,下行速度越快。大鼠小肠ICC微观结构及功能也出现相应同步损伤,表明ICC可能在快速进入高原胃肠动力紊乱形成机制中广泛参与并发挥重要作用。

Objective To study the influence of different altitudes and time points on small intestine electrical activity,the ultrastructure and physiological function of interstitial cells of Cajal（ ICCs） in high altitude exposed rats. Methods One hundred and thirty SD male rats were divided into three groups. Group A was located in low altitude（400 m）,and group B was located in moderate altitude（2 260 m）,and group C was located in high altitude（4 300 m）. On the basis of time points after entering the plateau,group B and C were further divided into six sub-groups,including groups of 1day,3 days,5 days,7 days,10 days,and 14 days. Each group contained 10 rats. Rats＇ small intestine electrical activity in different groups were measured. Immunofluorescence staining and electron microscopic were used to observe the physiological function and ultrastructure of ICCs in the small intestine. Results The amplitude and frequency of small intestine electrical activity of rats were the lowest in moderate altitude 5 days group and high altitude 3 days group（ P〈0. 05）. The reduction in high altitude 3 days group was more obvious（ P〈0. 05）. The physiological function and ultrastructure of ICCs were damaged in the small intestine. The gap junctions and organelles of ICCs were reduced in moderate altitude 5 days group and high altitude 3 days group,and apoptotic bodies were observed by electron microscope.The injury of rats in high altitude 3 days group was more obvious（ P〈0. 05）. The injury of high altitude on ICCs was also confirmed by c-kit immunofluorescence in moderate altitude 5 days group and high altitude 3 days group. Conclusion The small intestine electrical activity in rats was significant influenced by high altitude exposure,and the injury was more serious in higher altitude. The ultrastructure and function of ICCs in the small intestine was impaired in the same group. The results indicated that the ICCs played an important role in the small intestine dynamic disorders in high altitude exposed rats.