Study On The Development And Application Of Camellia Nitidissima Polyphenols Anti-type 2 Diabetes Mellitus

Objective:To observe the effect of Camellia nitidissima polyphenols（CNP）on blood glucose and pancreas of type 2 diabetic rats,and on proliferation of INS-1 cells.And its anti-STZ injury and anti-oxidant effects.To investigate its protective effects on the pancreas and anti-diabetic effects.Method:A rat model of type 2 diabetes mellitus was established by four weeks of high-glucose and high-fat diets and intraperitoneal injection of low-dose streptozotocin（STZ,30mg/kg）.Establish the normal group,high fat group,model group and CNP（50,100,200 mg/kg）group.Each CNP group was injected with STZ after 7 days of drug intervention.Measure fasting blood glucose（FBG）in each group,and harvest rat pancreas respectively on 1^st,2^nd,3^rdday.Make the pancreas into paraffin sections,and use Hematoxylin-Eosin（HE）staining and immunehistochemistry（IHC）to handle the sections.Observe the changes of pancreas histopathological and insulin secretion.INS-1 cell injury model was established by STZ（160μg/mL）for 24 hours.Establish the normal control group,injury group（STZ group）and prevention group（CNP 5,10,20μg/mL+STZ group）.INS-1 cells in logarithmic growth phase were seeded into 96-well plates at 1×10⁴ cells in each well.Given drugs by group when the cells were adherent.Detect the effect of CNP on the activity of INS-1 cells and the proliferation of STZ-injured cells by CCK-8 kit.INS-1 cell oxidative stress model was established by Cu²⁺（150μM）for 2 hours.Establish the normal control group,model group(Cu²⁺group),anti-oxidation group(Cu²⁺+CNP 5,10,20μg/mL group).Detect the effect of CNP on the proliferation of cellular oxidative stress model by CCK-8 kit.Detect MDA content in cell culture medium by MDA kit.Results:The FBG,morphology of isletβcells and positive rate of islet cells in model group were significantly changed,when compared with normal group and hyperlipidemia group.The FBG increased（P<0.05）and positive rate decreased（P<0.05）.When compared with the model group,the FBG of CNP middle and high dose（100,200 mg/kg）groups was significantly decreased（P<0.05）and showed a dose-dependent degree.The injury ofβcell was significantly decreased and the positive rate was significantly increased（P<0.05）.Low-dose of CNP group has no significant difference.When compared with the injury group,the cell survival rate of CNP high and medium dose（10,20μg/mL）groups was significantly increased（P<0.05）and cell morphology was more similar with normal control group.When compared with the oxidative stress model group,the cell survival rate was significantly increased（P<0.05）and MDA content was significantly decreased（P<0.05）in anti-oxidation groups that with medium and high dose CNP（10,20μg/mL）.Conclusion:CNP can reduce FBG in type 2 diabetic rats,protect rat pancreatic tissue and reduceβ-cell damage.It can also promote insulin secretion in rats and significantly reduce MDA in cells.It is suggested that CNP can protect pancreatic tissue to enhance the function ofβcells in secrete insulin and exert anti-diabetic effect,which is likely related to anti-oxidation and inhibition of oxidative stress.