RESUMO
This study aimed to reveal the constipation-relieving role of chitosan (COS) with different molecular weights (1 kDa, 3 kDa and 244 kDa). Compared with COS3K (3 kDa) and COS240K (244 kDa), COS1K (1 kDa) more significantly accelerated gastrointestinal transit and defecation frequency. These differential effects were reflected in the regulation of specific gut microbiota (Desulfovibrio, Bacteroides, Parabacteroides and Anaerovorax) and short-chain fatty acids (propionic acid, butyric acid and valeric acid). RNA-sequencing found that the differential expressed genes (DEGs) caused by different molecular weights of COS were mainly enriched in intestinal immune-related pathways, especially cell adhesion molecules. Furthermore, network pharmacology revealed two candidate genes (Clu and Igf2), which can be regarded as the key molecules for the differential anti-constipation effects of COS with different molecular weights. These results were further verified by qPCR. In conclusion, our results provide a novel research strategy to help understand the differences in the anti-constipation effects of chitosan with different molecular weights.