Effect Of Electroacupuncture On Shangjuxu Point (ST 37) To Calcium Sensing Receptor (CaSR) In Colonic Motility Abnormalities Mice

Objective:The aim of this study was to observe the effect of electroacupuncture (EA) on Shangjuxu point (ST 37) to calcium sensing receptor (CaSR) in colonic motility abnormalities mice, and explore the possible mechanism of EA regulating colonic motility.Methods:120 C57BL/6 mice were randomly divided into eight groups:nicardipine group, hexamethonium bromide group, normal saline (NS) group 1, NS group 2, nicardipine+EA group, hexamethonium bromide+EA group, NS group 1+EA group, NS group 2+EA group. Each group has 15 mice. The NS group 1 and NS group 1+EA group were injected with physiological saline of the same dose with nicardipine group, the NS group 2 and NS group 2 +EA group were injected with physiological saline of the same dose with hexamethonium bromide group. The EA groups were treated with EA bilateral Shangjuxu points, a total of five days intervention. After the intervention, the 12h fecal pellets, the percentage of fecal moisture, the colonic slow wave, the expression of CaSR were investigated by the multi-channel physiological signal acquisition system, immunofluorescence and confocal microscope.Results:(1) The 12h fecal pellets and percentage of fecal moisture results:Compared to day 0, the nicardipine group and hexamethonium bromide group’s fecal pellets of day 5 were reduced (respectively P=0.003, P=0.011), the nicardipine group’s fecal moisture percentage of day 5 were increased (P=0.02). Compared to NS group, the nicardipine group’s fecal pellets were reduced (P=0.011), but the percentage of fecal moisture has no significant difference (P=0.817); The fecal pellets and percentage of fecal moisture of hexamethonium bromide group both have no significant difference (respectively P=0.202, P=0.999). After EA intervention, the fecal pellets of nicardipine+EA group were increased compared to nicardipine group (P=0.028), the percentage of fecal moisture has no significant difference (P=0.800); The fecal pellets and percentage of fecal moisture of hexamethonium bromide+ EA group both have no significant difference compared to hexamethonium bromide group (respectively P=0.172, P=0.554); (2) The colonic slow wave results:The NS group’s slow wave was close to sine-like curve, minority part had a notch, which showed bimodal. The nicardipine group’s frequency was slower (P=0.000), and the amplitude was reduced (P=0.000); The hexamethonium bromide group’s frequency was faster (P=0.000), and the amplitude was reduced (P=0.000). After EA intervention, the frequency and amplitude of nicardipine+EA group and hexamethonium bromide+EA group both have significant difference separately compared to nicardipine group and hexamethonium bromide group (frequency, respectively P=0.000, P=0.000; amplitude, respectively P=0.000, P=0.000); (3) CaSR expression results:The NS group’s CaSR mainly expressed in intestinal epithelial cells, and the epithelial cells’s construction were uniform. The mucous layer structure of nicardipine group was destroyed, CaSR overall counts and fluorescence intensity were close to normal; The hexamethonium bromide group’s mucous layer structure was also destroyed, and had not too much CaSR, and the fluorescence intensity were decreased. After EA intervention, the nicardipine+EA group and hexamethonium bromide+EA group’s mucous layer structure were back to normal, overall CaSR and fluorescence intensity increased separately compared to nicardipine group and hexamethonium bromide group. But the hexamethonium bromide+ EA group’s overall CaSR counts and fluorescence intensity has significant difference compared to NS+EA group.Conclusions:(1) Injection of nicardipine can reduce the number of fecal pellets in mice, EA Shangjuxu point can improve above symptoms, indicating that EA may regulate colonic transit activity from this point; (2) EA Shangjuxu point can regulate slow wave frequency and amplitude resulted from nicardipine, hexamethonium injection, thereby to improve colonic motility disorders; (3) EA Shangjuxu point can adjust the overall counts of CaSR and fluorescence intensity, and repair the mucous layer structural disorder, which may be possible therapeutic mechanism of EA for colonic motility disorders.