RESUMO
Aging can cause degenerative changes in the function of multiple tissues and organs in the body. Gastrointestinal diseases and intestinal dysfunction are very common in the elderly people. The purpose of this study is to explore the effect of the total extract of Astragalus membranaceus (Fisch.) Bge. on intestinal function and gut microbiota homeostasis in natural aging mice, which will provide clues for further mechanism study. The natural aging mice model is established and animal experiments follow the regulations of the Animal Ethics Committee of Nanjing University of Traditional Chinese Medicine. The overall health of the mice was evaluated by the "frailty index" scoring method. The intestinal absorption and transport function were measured by detecting intestinal glucose absorption capacity, transport time, lipase and amylase activities of aging mice. Intestinal inflammation was assessed by detecting inflammatory cytokines by enzyme-linked immunosorbent assay (ELISA). The pathological changes in the intestines of aging mice were tested by hematoxylin-eosin (H&E) staining and alizarin blue (AB) staining. The qRT-PCR method was used to explore the gene transcription level related with the proliferation and differentiation of intestinal stem cells. Microbiota analysis based on 16S rDNA were used to evaluate the composition of gut microbiota. The results showed that Astragalus had a tendency to reduce the "frailty index" of aging mice, but did not show a significant difference. In some indicators of aging phenotype, Astragalus has the most significant effect on hair loss and physical fitness. In terms of intestinal function, Astragalus could increase intestinal glucose absorption capacity, shorten intestinal transportation time and promote lipase secretion in aging mice. The levels of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) in the aging intestinal tissue were reduced after Astragalus administration. Astragalus also ameliorated the pathological degeneration of the intestinal tissue of aging mice by increasing the length of small intestinal villi, the thickness of colonic mucosa and goblet cell number. In addition, Astragalus elevated the expression of genes associated with the proliferation and differentiation in jejunum and modulated gut microbiota, especially restoring the abundance of Lachnospiraceae. Taken together, the above research results demonstrate the total extract of Astragalus as a key factor improving the intestinal function and gut microbiota homeostasis of aging mice.