The Effect Of Glycine On Rats With Non-alcoholic Fatty Liver Disease

Objective:Rat nodels of NAFLD were established by giving a fat-riched diet.To explore the role of endotoxin in the pathogenesis of non-alcoholic fatty liver(NAFLD),expression of COX-2 in fatty liver and the effect of glycine on COX-2 of rats liver with non-alcoholic fatty liver disease.Methods:54 rats were randomly divided into 3 groups:control group,.high fat-fed group and high fat-fed+glycine group.These rats were sacrificed at the 8th,12th,16th weekend during the study.The blood of abdominal aorta was obstained and the levels of serum endotoxin,ALT, TG and MDA in liver were measured.The isotope-selective nondispersive infrared spectrometer (NDIRS)was applied to practice the ¹³C- methacetin breath test and peak calue of breathing (DOB),cumulative expiration within 60 min(CUM⁶⁰)were determined.Histopathology of liver tissue was analyzed by light microscope and in the same time the expression of COX-2 in liver tissue was detected by immunohistochemistry and RT-PCR.Results(1)The weight and liver index in high fat-fed group were significantly higher than in control and glycine group(P＜0.05).The result shows a tendency to increase.(2)The level of ALT in high fat-fed group werenot significantly higher than in control and glycine group in 8th weekend.(P＞0.05).But in 12th and 16th weekend the level of ALT were significantly higher than in control and glycine group(P＜0.05)and at 16th weekend maintains a high level.(3)The level of DOB and CUM⁶⁰in ¹³C -methacetin breath test of fat-fed group were significantly lower than in control and glycine group(P＜0.05)(4)In 8th and 12th weekend the level of endotoxin in high fat-fed group werenot significantly higher than in control and glycine group(P＞0.05).But in 16th weekend the level were significantly higher than in control and glycine group(P＜0.05).(5)The level of MDA in high fat-fed group werenot significantly higher than in control and glycine group in 8th weekend(P＞0.05).But in 12th and 16th weekend the level of MDA in high fat-fed group were significantly higher than in Control and glycine group(P＜0.05)(6)Hepaticpathology diagnosed them as mild,moderate and heavy fatty liver.(7)Immunohistochemistry the expression of COX-2 was negative in the control and high fat-fed group of 8th and 12th weekend.But was positive in high fat-fed group and glycine group of 16th weekend Computer analysis indicated there were significant differences among the control,high fat-fed group and glycine group (P＜0.05).(8)By RT-PCR the expression of COX-2 have the same result with immunohistochemistry.(9)The results of correlation analysis:The result of correlation analysis between plasma endotoxin and ALT is significant positive correlation,r=0.93,P＜0.01;The result of correlation analysis between plasma endotoxin and MDA is significant positive correlation,r=0.68,P＜0.01;The result of correlation analysis between plasma endotoxin and liver COX-2 is significant positive correlation,r=0.58,P＜0.01.Conclusion:1 Glycine could attenuate the development of NAFLD.2 There were endotoxemia in NAFLD and Glycine could attenuate the level of endotoxemia and the expression of cox-2,which could prevent NALFD.