The Detection And Significance Of Leptin And Its Receptors In Experimental Fatty Liver And Hepatic Cirrhosis

Objective To observe the changes of serum leptin,the expression of the leptin receptors in the liver of experimental fatty liver and hepatic cirrhosis ,and to discuss the possible mechanisms and significance .Method Fatty liver model rats were made by orotic acid douche,cirrhosis were made by injection of thioacetamide(TAA),and control group was made at the same time.The rats ' height and weight, Lee' s index were measured during the experiment .The serum fatty acids were measured respectively.The levels of leptin were measured by ELISA.The expression degree and location of leptin receptors were observed by immunohistochemistry stain and measured by image analysis system.Result Fatty liver and hepatic cirrhosis models were successfully constructed.The levels of serum leptin of fatty liver group significantly increased compared with control group(P< 0.01).Serum leptin of hepatic cirrhosis group significantly increased compared with control group(P<0.01),and there was no significant difference between the serum leptin of the fatty liver group and hepatic cirrhosis group(P> 0.05).The expression of leptin receptors in fatty liver significantly decreased compared with control group(P < 0.05).Leptin receptors in cirrhosis significantly increased compared with contol group(P<0.01),and leptin receptors were significantly higher in cirrhosis rats than those in fatty liver group(P< 0.05).Moreover, the serum leptin was closely relevant to TG in fatty liver group(r= 0.927, P<0.05),the serum leptin was closely relevant to TC in hepatic cirrhosis group(r=0.918, P<0.05).Conclusion We have observed for the first time leptin and its receptors in experimental fatty liver and hepatic cirrhosis and the relations between the hepatic injury development.Serum leptin increased and closely related to the free fatty acids,this suggested that the serum leptin take part in the liver adiposedenaturation.Leptin receptors were significantly decreased or inhibited in fatty liver,this suggested that free fatty acids may inhibit leptin receptors gene expressions there were leptin resistance.Serum leptin was abnormal and correlated with TC in hepatic cirrhosis,this suggested abnormal metabolism of serum fatty acids might contribute to expression of leptin.Leptin receptors significantly increased in hepatic cirrhosis,and obviously in liver cells regeneration and sinusoidal endothelial cells.These observations suggested leptin appear to promote profibrogenic responses in the liver.Our study results not only provide experiment basis for us to research the mechanisms of fatty liver and hepatic cirrhosis,but also establish theory foundation to prevent and treat all types of hepatic injury.