Effect of astragalus polysaccharide combined with urine stem cell transplantation on type 2 diabetes in rats

Objective To study the effect of astragalus polysaccharides combined with hUSCs transplantation on type 2 diabetic rats. Methods Twenty-five SD rats were randomly selected into the normal control group, and the remaining 105 SD rats were used to establish type 2 diabetes model. The 100 rats successfully modeled were randomly divided into the diabetes group, astragalus polysaccharide treatment group, hUSCs treatment group, and astragalus polysaccharide + hUSCs treatment group, with 25 rats in each group. After 2 weeks of treatment, the FBG concentration, insulin and C-peptide concentrations, and body weight changes were measured in each group. The distribution and survival of PKH-26-labeled hUSCs in rat pancreatic tissue were observed by fluorescence microscopy. TUNEL method was used to detect the apoptosis of rat islet cells. Real-time quantitative PCR and Western Blot were used to detect the expression of TGF-β/Smad signaling pathway-related genes in rat pancreatic tissue. Results The FBG concentration of rats in the astragalus polysaccharide treatment group, hUSCs treatment group and astragalus polysaccharide+hUSCs treatment group were significantly decreased, and that in the combination treatment group was significantly lower those in the astragalus polysaccharide group and hUSCs group, and the differences were statistically significant(all P<0.05). Compared with the diabetic group, the insulin concentration, C-peptide concentration and body weight in the astragalus polysaccharide treatment group, hUSCs treatment group and combination treatment group rats were significantly increased, and those in the combination treatment group was significantly higher than those in the astragalus polysaccharide treatment group and in the hUSCs treatment group, the differences were statistically significant (all P<0.05). The results of fluorescence microscopy showed that the number of PKH-26 positive hUSCs in the combined treatment group was 74.64±9.75 in each high power field, which was significantly higher than that in the hUSCs treatment group (43.64±5.83), the difference was statistically significant (P<0.05). Compared with the diabetic group, the apoptotic rates of islet cells in the astragalus polysaccharide treatment group and the hUSCs treatment group were reduced, and the relative expressions levels of mRNA and protein of TGF-β1, Smad3, and Smad7 in the pancreatic tissue were also significantly reduced(all P<0.05). The reduction was more significant in the combination treatment group, and the differences were statistically significant (all P<0.05). Conclusions Astragalus polysaccharide combined with hUSCs transplantation can effectively reduce the FBG concentration, increase the concentration of insulin, C-peptide and body weight, reduce the apoptosis of pancreatic islet tissue, which may be related to the reduction of TGF-β/Smad in pancreatic tissue. Signaling pathways are involved in suppressing the inflammatory response. Key words: Astragalus polysaccharide; Human urine-derived stem cells; Transplantation; Diabetes mellitus, type 2; Rat