Intervention Of Jellyfish Peptide On Glucose And Lipid Metabolism Disorder In Type 1 Diabetic Mice

There are highly abundant active substances in the ocean that have biological functions.Peptides are an important class of active molecules in the screening of marine biological active substances.Jellyfish,as a type of traditional marine organisms of the same origin as food and medicine,is widely distributed in the coastal areas of China.The main components of jellyfish are water and protein,the most abundant of which is collagen.Traditional medicine and modern biotechnological studies have shown that jellyfish can treat hypertension,asthma,lower phlegm,remove dampness,lower blood fat,anti-oxidation and other effects.With changes in people’s dietary habits and lifestyle,glucose and lipid metabolism disorders have resulted in a wide range of diseases,such as diabetes,cardiovascular disease,fatty liver,cirrhosis,and so on.Glucose metabolism and lipid metabolism are closely related.Long-term high blood sugar in the body can cause lipid metabolism disorders,build up fat in the liver,and worsen organ damage.Studies have shown that patients with type 1 diabetes have abnormal lipid metabolism at an early stage of the disease.Recently research indicates that the intestinal microbial has a clear correlation between glucose and lipid metabolism.By adjusting the balance of intestinal microbial,diseases caused by disorders of glucose and lipid metabolism can be alleviated.In this study,jellyfish peptides were used to interfere with glucose and lipid metabolism disorders in a mouse model of type 1 diabetes,and the mechanism of action was studied,so as to provide experimental evidence for the production and use of jellyfish peptides in clinical adjuvant therapy.ObjectiveThe jellyfish peptide was prepared by enzymatic hydrolysis to detect whether jellyfish peptides could regulate glucose and lipid metabolism disorder and organ damage in type 1 diabetic mice.It was verified that jellyfish peptide could regulate blood glucose and lipid in mice by regulating immune function and promoting intestinal flora balance.Methods1.Hydrolyze the jellyfish with alkaline protease and bromelain respectively to obtain two groups of jellyfish peptides with different molecular weights2.Randomly divide BALB/C male mice into four groups: control group(NC),natural recovery group(DM),jellyfish peptide 1 recovery group(DM+JP),jellyfish peptide 2 recovery group(DM+BP).The control group was intraperitoneally injected with an equal volume of sodium citrate buffer,and the remaining three groups were intraperitoneally injected with STZ to establish the glucose and lipid metabolism disorder model of type 1 diabetic mice.After 55 days of the experiment,all mice were sacrificed under aseptic conditions,and mouse serum,pancreatic tissue,liver tissue,kidney tissue,and colon tissue were collected for use.3.The effect of protease hydrolysis on jellyfish was detected by electrophoresis;the changes of glucose metabolism were measured by random blood glucose and glycosylated serum protein in mice;detect changes in the levels of lipid metabolism indexes TC,TG and antioxidant capacity indexes SOD and MDA in mice;the organ injury of mice was judged by organ index;tissues of pancreas,colon,liver and spleen were taken for pathological evaluation by H&E staining;the levels of inflammatory cytokines in mice were evaluated by ELISA;immunohistochemistry and Western Blotting methods were used to detect changes in the chemical barrier and mechanical barrier of the mouse colon.4.Total DNA was extracted from the feces of mice,and the structural changes of intestinal microbiota were preliminarily evaluated by PCR-DGGE technology.Then the high-throughput sequencing technology of the 16 S rRNA gene of the intestinal microbiota was used to analyze the composition and changes of the microbiota in the mouse intestine perform precise species analysis.Results1.Jellyfish collagen was hydrolyzed,respectively,by alkaline protease and bromelain,and jellyfish peptide 1 and jellyfish peptide 2 were obtained with a mean molecular weight of less than 10 KDa.After intragastric administration to mice,it was found that the two types of jellyfish peptides played an important role in controlling the lipid metabolism disorder of mice and,to a certain extent,the organ damage,anti-oxidation,immune function and intestinal microbiota of mice.However,there is no significant recovery effect on glucose metabolism disorder in mice.2.STZ caused a significant decrease in the index of mouse thymus,decreased index of spleen,decreased immune function,increased index of liver and kidney,and damage to liver and kidney organs.All the affected indexes recovered to a certain degree following gavage with jellyfish peptide.3.Pathological analysis of the mouse tissues showed that the pancreatic islets of the model group were loose in structure,small in size and unclear in boundary with surrounding tissues;liver cells were swollen,fatty vacuoles were occasionally seen,and inflammatory cell infiltrations were seen in the interstitium;the dividing line between red pulp and white in spleen was not obvious;inflammatory reaction occurred in colon tissue and gland arrangement was disordered.The islet contour of mice in the recovery group was slightly clear;the fat vacuoles of hepatocytes disappeared and the swelling of hepatocytes was reduced;the spleen tends to normal structure;the muscle layer of colon tissue was relatively thickened,and the inflammatory reaction was significantly reduced or even disappeared.4.After intraperitoneal injection of STZ,the levels of serum IL-1β,IL-6,TNF-αand LPS were increased.After gavage with jellyfish polypeptide,all indexes decreased.5.After intraperitoneal injection of STZ,the intestinal microbiota of mice was disturbed.In the model group,the abundance of intestinal microbiota decreased,the proportion of Firmicutes increased,Cyanobacteria disappeared,and the proportion of Verrucomicrobiaceae decreased.After gavage with jellyfish polypeptide,the diversity of the intestinal microbiota recovered,the Cyanophyta recovered,and the proportion of Lachnospiraceae and Verrucomicrobiaceae increased.Immunohistochemistry and Western Blotting results of colon tissue showed that the expression of MUC2 in colon of mice was increased after gavage of jellyfish peptide,suggesting that the intestinal chemical barrier was enhanced.The expression of intestinal tight junction proteins Claudin and ZO-1 both increased,suggesting that the intestinal mechanical barrier was repaired and the intestinal permeability decreased.Conclusions1.Jellyfish peptides can improve lipid metabolism disorder and enhance antioxidant level,and have a certain protective effect on organs,but have little effect on the regulation of blood sugar.2.Jellyfish peptides can effectively regulate immune function and protect the intestinal barrier including intestinal microbiota.3.The jellyfish peptide prepared by alkaline protease has a better intervention effect on the model than those prepared by bromelain.