Sichuan Provincial Key Laboratory for Food Safety Monitoring and Risk Assessment, West China School of Public Health, Sichuan University, Chengdu, Sichuan 610041, China
Abstract：Objective To explore the laxative efficacy and mechanism of aloe vera freeze-dried powder, senna extract alone and in combination with Panax quinquefolium extract in mice with constipation. Methods One hundred and eighty male Kunming mice were randomly divided into 9 groups, including the blank group, the model group, the 10-fold aloe group (the L1 group), the 20-fold aloe group (the L2 group), the 10-fold senna group (the F1 group), the 10-fold aloe + 10-fold Panax quinquefolium group (the L1X1 group), the 20-fold aloe + 20-fold Panax quinquefolium group (the L2X2 group), the 10-fold senna + 10-fold Panax quinquefolium group (the F1X1 group) and the 20-fold senna + 20-fold Panax quinquefolium group (the F2X2 group). After 14 days of treatment, constipation mouse models were established by intragastric administration of 6 mg/kg loperamide hydrochloride suspension. Start time of the first black feces defecation, the amount of black feces within 6 hours and gastrointestinal transit ratio were observed to evaluate the effects of the laxatives tested on constipation. The serum levels of acetylcholinesterase (AchE) and the mRNA expression of glial cell-derived neurotrophic factor (GDNF) in small intestines were measured to explore the mechanism of action. Results There was no significant difference in body weight on 0 d (F=1.627, P=1.121), 7 d (F=1.588, P=0.132) and 14 d (F=1.571, P=0.137) among the groups. As compared with the model group, start time of the first black feces defecation was shortened and the amount of black feces within 6 hours increased in the dose groups. There was no significant difference in the total length of small intestine among the groups (F=0.424, P=0.903), but statistically significant differences were found in the length of ink propulsion (F=9.857, P<0.001) and the rate of ink propulsion (F=10.489, P<0.001) among the groups. As compared with the model group, the length of ink propulsion and the rate of ink propulsion in the L2 group, the L1X1 group, the L2X2 group and the F2X2 group significantly increased (P<0.05). The length of ink propulsion and the rate of ink propulsion in the L1X1 group significantly increased (P<0.05) as compared with the L1 group. The serum level of AchE showed statistically significant differences among the groups (F=2.447, P=0.016). The serum level of AchE in the L2X2 group and the F1X1 group significantly increased as compared with that in the model group (P<0.05). The mRNAexpression levels of GDNF in small intestine tissues of each group were statistically different (F=101.158, P<0.001).As compared with the model group, the mRNA expression levels of GDNF in small intestines of the L1 group, the L2 group, the L2X2 group and the F2X2 group were significantly up-regulated (P<0.05). Conclusions The efficacy of the above-mentioned laxatives on constipation in mice of the L2 group, the L1X1 group, the L2X2 group and the F2X2 group was good; moreover, combined use of two laxatives was more effective. The mechanism of action may be associated with promoting AchE release and increasing the expression of GDNF in small intestines.
2020, Vol. 27 
