Protective effects and mechanisms of opuntia polysaccharide in animal models of diabetes mellitus: A systematic review and meta-analysis

Opuntia speciesis used in traditional medicine to treat diabetes mellitus (DM). Polysaccharide is one of the main components of Opuntia. Opuntia polysaccharide (OPS) is a kind of natural active macromolecular substance, numerous animal experiments have been conducted to treat DM, however, its protective effect and mechanism in animal models of DM has not been clarified.The aim of this study is to evaluate the efficacy of OPS on DM through a stematic review and meta-analysis of animal models, and whether its improves blood glucose (BG) levels, body weight (BW), food intake, water intake, and lipid levels, and to summarize the potential mechanism of OPS in the treatment of DM.We searched relevant Chinese and English databases from the date of construction to March 2022, including PubMed (MEDLINE), Embase, Cochrane Library, Scopus and Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedicine Literature Database (CBM), Chinese Science and Technology Periodicals Database (VIP), Wanfang Database. 16 studies were included for meta-analysis.The results showed that compared with the model group, the OPS significantly improved BG, BW, food intake, water intake, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Meta-regression and subgroup analysis showed that intervention dose, animal species, duration and modeling method may be the source of the heterogeneity. There was no statistical difference between the positive control group and the OPS treatment group in improving BW, food intake, water intake, TC, TG, HDL-C, and LDL-C.OPS can effectively improve the symptoms of hyperglycemia, polydipsia, polyphagia, low body weight, and dyslipidemia in DM animals. The possible protective mechanisms of OPS on DM animals are immune regulation, repair of damaged pancreatic β cells, and inhibition of oxidative stress and cell apoptosis.