Effects of Si-Jun-Zi decoction polysaccharides on cell migration and gene expression in wounded rat intestinal epithelial cells

Si-Jun-Zi decoction (SJZD), a traditional Chinese herbal prescription, has been used clinically for treating patients with disorders of the digestive system. Previous studies indicated that the polysaccharides of SJZD (SJZPS) are the active components contributing towards its pharmacological effects in improving gastrointestinal function and immunity. However, the protective and restitutive effects on intestinal epithelial cells remain unknown. In the present study, SJZPS were first extracted and chemically characterized. Then their stimulatory and restitutive effects on intestinal epithelial cells (IEC-6 cells) were elicited by different in vitro models including migration of wounded IEC-6 cells and cell proliferation. Results indicated that SJZPS not only protects the cells against the harmful impairment of indomethacin but also enhances re-epithelialization of a wounded monolayer at an optimal dose of 100 mug/ml at 24 h incubation. To elucidate the modulatory effect of SJZPS on wounded IEC-6 cells at the molecular level, an oligonucleotide microarray was employed to study differential gene expression of SJZPS-treated IEC-6 cells and the candidate genes were validated by RT-PCR. There was increased expression of genes coding for ion channels and transporters, which are critical to cell migration and restoration of wounded intestinal cells, suggesting a possible mechanism for re-epithelialization. In conclusion, our data show for the first time that SJZPS can enhance intestinal restitution and protect against indomethacin-induced damage of intestinal epithelial cells. These findings provide new insight into the mechanism of action of a traditional Chinese herbal prescription, SJZD, in intestinal wound restitution.