Protective Effects Of Polysaccharides From The Ink Of Ommastrephes Bartrami On Cyclophosvnamide-induced Mucosa Epithelial Cell’s Injury In Mice Small Intestine

Cyclophosphamide is a kind of chemotherapy drugs, which always causegastrointestinal side effects and mucosal injury. The use of drugs for the treatment ofgastrointestinal reactions have certain limitations. Squid ink is one of the abundantmarine biological resources that have long medicinal history.The main component ofsquid ink is melanin and proteoglycan complex. In recent years, squid inkpolysaccharide is confirmed to have a variety of physiological activities, such aspromoting immunity and anti-tumor activity. The main purpose of this study is toinvestigate the protective effects of squid ink polysaccharide oncyclophosphamide-injured intestinal mucosal epithelial cells in mice. The achivement ofthis study will provide a theoretical basis for the development of functional food withsquid ink polysaccharide to help patients with intestinal mucosal damage.This thesis consists of three main parts:1. Purification of polysaccharide from squid ink and establishment of intestinalmucosal injuried animal model. Crude melanin-free polysaccharide of Ommastrephesbartrami was obtained with a yield of1.5%, followed by centrifugation, papaindigestion and ethanol precipitation. The chemical composition of content are asfollowing: total sugar is60.99%, total protein is9.44%. Preliminary experiment suggeststhat the appropriate dose of cyclophosphamide intraperitoneal injection is two days of50mg/kg.bw, the gavage doses of squid ink polysaccharide are: low-dose group50mg/(kg.bw), middle-dose group100mg/(kg.bw), high-dose group200mg/(kg.bw).2. Research of the protective effects about squid ink polysaccharide on miceintestinal mucosal epithelial cells. With the changes of body weight, occurrence ofdiarrhea, intestinal morphology changes include villi length and crypt depth, our dataindicated that squid ink polysaccharide could protect intestinal mucosae from cyclophosphamide-induced damage. Further research showed that squid inkpolysaccharide could enhance the body’s antioxidant capacity, increase the expression oftight junction protein, and thus maintain the morphology of intestinal microvilli.3. Investigation of the protecive effects about squid ink polysaccharide on Panethcells and Goblet cells in mice intestinal. The effects and mechanisms of squid inkpolysaccharide on Paneth cells (crypt) and Goblet cells (villi) were examined,respectively, after separating of small intestinal crypts and villi with cryogenic WeisserAprecipitation method. Our results showed that cyclophosphamide could reduce thesecretion of antimicrobial peptides in Paneth cells and also Goblet cells, while squid inkpolysaccharide has a significant role in the improvement. Further research showed thatsquid ink polysaccharide could promote the secretion of antimicrobial peptides in Panethcells by limitting endoplasmic reticulum stress response, and increases secretion ofantimicrobial peptides in goblet cell by increasing the number of these cells.In sum, this study showed that squid ink polysaccharide has significant protectiveeffects on cyclophosphamide-injuried intestinal mucosal epithelial cells in mice. It willprovide a theoretical basis for the development of functional food with squid inkpolysaccharide. The utilization of squid ink polysaccharide will not only bring thegospel to chemotherapy-induced intestinal mucosal injury patients, but also conducive tothe high-value use of squid ink resource.