Systematic Effect of Modified Renshen Wumeitang in Regulation of GABA Signaling Pathway in Rats with Diarrhea / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effect of modified Renshen Wumeitang（MRWT） on the related regulatory factors of the γ-aminobutyric acid （GABA） signaling pathway in colon tissues of rats with diarrhea， and reveal the mechanism of MRWT in invigorating Qi， generating fluid， and checking diarrhea. MethodForty-eight SD immature rats were randomly divided into a blank group （n=12） and an experimental group （n=36）. The diarrhea model was induced in the experimental group by Sennae Folium combined with overstrain and improper diet for 14 days. Subsequently， the model rats were randomly divided into a model group （normal saline， 20 mL·kg-1）， a western medicine group （Medilac-Vita， 0.7 g·kg-1）， and a Chinese medicine group （MRWT， 35 g·kg-1）， with 12 rats in each group. The rats in the blank group received normal saline at 20 mL·kg-1， and those in the other groups were treated correspondingly， once a day for 7 days. The general condition， loose stool rate， and diarrhea index of the rats were observed daily. Immunohistochemistry was used to detect the optical density expression of GABA protein in the colon of rats. The content of phosphatidylinositol-3 kinase （PI3K）， protein kinase B2 （Akt2）， phosphorylated Akt （p-Akt）， and interleukin-1β （IL-1β） was determined by enzyme-linked immunosorbent assay （ELISA）. The mRNA and protein expression levels of PI3K， Akt2， and GABA type A receptor subunit β2 （GABRB2） in the colon of rats were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot， respectively. ResultCompared with the blank group， the model group showed worsened general condition， The difference was not statistically significant of loose stool rate and diarrhea index， increased expression of GABA protein （P<0.05）， elevated expression of PI3K， Akt2， p-Akt， and IL-1β （P<0.05， P<0.01）， and up-regulated PI3K， Akt2， and GABRB2 mRNA and protein expression （P<0.01）. Compared with the model group， the western medicine group and the Chinese medicine group showed the improved general condition， decreased loose stool rate and diarrhea index （P<0.01）， and decreased content of PI3K， Akt2， p-Akt， and IL-1β （P<0.05）. The Chinese medicine group displayed decreased mRNA expression of PI3K， Akt2， and GABRB2 （P<0.05， P<0.01） and down-regulated protein expression of GABA， PI3K， and GABRB2 （P<0.05， P<0.01）. The western medicine group exhibited down-regulated mRNA expression of PI3K，Akt2，and protein of PI3K （P<0.05）. ConclusionMRWT can regulate the GABA signaling pathway， reduce Cl- flow in intestinal epithelial cells to the intestinal lumen， and improve the imbalance of colonic fluid metabolism in the colon of diarrhea rats， thereby exerting its effects of invigorating qi， generating fluid， and checking diarrhea.