钙调神经磷酸酶在兔胆囊切除术后早期Oddi括约肌改变中的作用

目的观察胆囊切除术后早期Oddi括约肌超微结构改变、肌球蛋白重链（MHC）及钙调神经磷酸酶（CaN）催化亚单位α、β（CnAα、CnAβ）2种亚型的表达变化,探讨胆囊切除术后Oddi括约肌的改变及其可能的机制。方法52只新西兰大白兔,分为4组,A、D组各14只,B、C组各12只;A组仅行开腹术暴露胆囊,术后4周取Oddi括约肌标本;B、C、D组行胆囊切除术,分别于术后2、4、8周切取标本。A、D组各取2只行透射电镜检测。余行RT-PCR、Western blot检测CnAα、CnAβ mRNA和蛋白表达变化,Western blot检测MHC蛋白表达变化。结果①Western blot检测到术后2周、4周、8周MHC蛋白表达逐渐增加（P〈0.01）;透射电镜示术后8周平滑肌细胞内密体增多。②RT-PCR检测到术后4周、8周与对照组比CnAβ mRNA表达增加,8周比4周降低（P〈0.01）。③Western blot检测到术后2周、4周、8周CnAβ蛋白表达逐渐增加（P〈0.01）。④CnAα mRNA及蛋白表达均无显著变化。结论兔胆囊切除术可致Oddi括约肌组织超微结构发生改变、肌球蛋白重链表达增加;肌球蛋白重链表达增加可能与CnAβ表达增高有关,这可能是Oddi括约肌功能紊乱（SOD）多发生于胆囊切除术后患者的分子机制之一,可能在胆囊切除术后SOD的发病过程中起一定的作用。

Role of Calcineurin in the Early-stage Change of Sphincter of Oddi after Cholecystectomy in Rabbit

Objective To explore calcineurin role in the change of sphincter of Oddi （SO） at the early-stage after cholecystectomy by investigating the changes of functional proteins and structure of sphincter of Oddi,and detecting the different expressions between the main two catalytic subunits of calcineurin： CnAα and CnAβ.Methods Fifty-two adult New Zealand rabbits were randomized into four groups： A （n=14）, B （n=12）, C （n=12） and D （n=14）. The rabbits in the group A were only subjected to laparotomy and bred for 4 weeks, while those in groups B, C and D were subjected to cholecystectomy and bred for 2, 4 and 8 weeks respectively. All rabbits were sacrificed, and their sphincter of Oddi was taken for electron microscopic examination （2 respectively from groups A and D） and the mRNA and protein expressions of CnAα and CnAβ, as well as MHC protein expression.Results Western blotting results showed the protein expression of MHC increased at the end of 2nd, 4th, 8th week after cholecystectomy （P〈0.01）. Electron microscopic examination showed dense bodies in smooth muscle cells increased in group D compared with group A. RT-PCR results displayed compared with control group, the mRNA expression of CnAβ increased in 4, 8 weeks after cholecystectomy （P〈0.01）, but decreased at 8th week compared with that at 4th week. Western blotting results exhibited the protein expression of CnAβ increased gradually in 2, 4 and 8 weeks after cholecystectomy （P〈0.01）. There was no difference in mRNA and protein expression of CnAα in the whole process.Conclusion The protein expression of myosin heavy chain （MHC） increased and the ultrastructure of SO cells changed after cholecystectomy. The increase of CnAβ might play a role in the increase of MHC after cholecystectomy, which may be one molecular mechanism that sphincter of Oddi dysfunction is more frequently recognized after cholecystectomy.