Effect of vincristine on the myoelectric activity and motility of the small intestine in rats / 中华消化杂志

ABSTRACT

Objective To investigate the effects of vincristine on myoelectric activity and motility of the small intestine in conscious rats and its mechanism. Methods Seventy-two SD rats were divided into six groups. The rats in control group were received 0.9% NaCl solution (n=18). The rats in group B were injected with vincristine and subdivided into 0.25 mg/kg(n=6) ,0.5 mg/kg(n=6)and 0.75 mg/kg groups. The group C and D was false operation (n=6)and false operation plus injection with 0.75 mg/kg of vincristine(n=6), respectively. The group E and F was subdiaphragmatic vagotomy plus 0.9% NaCl (n=6) or subdiaphragmatic vagotomy plus 0.75 mg/kg of vincristine (n=6), respectively. The myoelectric activity and motility of the small intestine were recorded. The frequency and area under the curve of slow wave, the periodicity of the migrating myoelectrie complex (MMC) and the duration of MMC Ⅲ were analyzed. The expressions of the myenteric neurons and interstitial cells of Cajal were evaluated by immunofluorescence stain. Results The myoelectric activity in 0.25mg/kg group was not different from the controls, but it changed in 0.5 mg/kg and 0.75 mg/kg groups which correlated with the time of vincristine injection. The irregular spike activity arose and accompanied with disruption of the MMC at (51±14.27) minutes,but recovered at (78.33±13.08) minutes. The periodicity was shorter in 0.5mg/kg [(343.17±142.93)s]and 0.75 mg/kg groups [(302.67±66.67)s] compared with controls [(740.22± 98.92) s, F=31.325, P<0.01]. Three days after vincristine administration, the area under the curve of slow wave decreased to (2.56±0.30) mV·s in 0.5 mg/kg group and (2.57±0.56) mV·s in 0.75 mg/kg group compared with the controls ((4.10±0.80) mV·s , F = 11.442, P<0.01). The intestinal propulsive rate was lower in 0.75 mg/kg group compared with the controls [(33.59±1.43) vs(60.34±2.41)%,t= 23.36, P<0.01]. The expression of the interstitial cells of Cajal was less than those in controls. Three days later, the area under the curve of slow wave in F group was less than that in controls. Conclusions Vincristine provokes alterations of myoelectric activity and motility of the small intestine. The early vincristine-induced escalating in myoelctric activity of the small intestine is through vagus nerve pathway. The decreased motility is contributed to the damage of the interstitial cells of Cajal.