Objective:To investigate the relationship between motor abnormality of sphincter of Oddi (SO) and hepatolithiasis.
Methods :The hepatolithiasis rabbit models were established in adult rabbits(n=64) which were randomly divded into 2 groups:control group （n＝16）and experimental group(n=48),including 2 wk,4 wk and 8 wk group（n＝16 per group）. During the formation process of hepatolithiasis, bile character and ratio of stone formation were both observed, then the myoelectric waves of SO were recorded.Finally, The SO segment was sliced and observed by transmissional electron microscope.
Results:The rate of true stone formation in group 8 wk（68.75％,11/16）was higher than that in group 4wk (12.50％,2/16)and in group 2wk (0.00％,0/16). Compared with the control group, there was significant decrease of both SO myoelectric peak amplitude and SO myoelectric frequency in the experimental group. Electron microscopy showed that SO cells in control group and 2wk group had no change, but the 4wk and 8wk groups underwent changes including fibrolysis of myofilament, increase of collagen fibers, fusion and thickening of microfilament, decrease and array disorder of macula densa, swelling of chondrosome and endoplasmic reticulum, widening of perinuclear space and deviation and pyknosis of nucleus, and formation of inclusion body in cytoplasm; and the degeneration degree in 8wk group was obvious than that in group 4wk.
Conclusions:The functional abnormality of SO may contribute important effects on the formation of hepatolithiasis. Fibrous degeneration of SO maybe the pathogenesis of functional abnormality of SO.