The Expression Of Endogenous Cannabinoid Receptors In Liver Fibrosis In Mouse Infected With Schistosoma

Objective:To investigate the expression of endogenous cannabinoid receptors in the liver of mouse infected with schistosoma japonicum, so as to explore the further mechanisms of schistosoma of liver fibrosis .Methods:Thirty mice were randomly divided into two groups the control group (10) and the model group (20). The mouse in the model group was infected with schistosoma japoni- cum by transfer of the cercaria to its abdominal space. Twelve weeks later the livers and plasma were harvested. Morphology was examinated by HE and electron microscope. We use immunohistochemistry,RT-PCR and Western-blot to measure the expression of CB receptor 1 and CB receptor 2 in the normal liver and the model liver that infected with schistosoma japonicum.Results:The morphological examinations showed typical pathological changes in liver fibrosis with worm tubercles of schistosoma japonicum deposited in the liver tissue, fibrosis around the worm tubercles and infiltration or soakage of inflammatory cells, there were denaturalization,atrophy and regeneration in hepatocytes, no obviously necrosis, by which we supposed that the model was successful, but in the normal liver the structure was natural. The immunohistochemistry showed that in normal liver there was separated expression of CB1 receptor in enchylema of hepatocytes and around the portal vein, expression of CB1 receptor positive is low, however these expressions increased in mouse liver infected with schistosoma japonicum. The results of RT-PCR and Western-blot both showed the same results as the result of immunohistochemistry that the expression was increased in model group compared with the normal group, the difference was significant in statistics(P<0.05). We saw the same results in the expression of CB2 receptor, but there were much expression of CB2 receptor in the inflammatory cells around the worm tubercules of S. japonicum showed in the immunohistochemistry, no expression of cannabinoid receptor 1 in the immunocytes. We also found that in enchylema of hepatocytes that nearer to the worm tubercules of S. japonicum there was much more expression of CB2 receptor, which maybe associated with the degree of the injury.Conclusions:The expression of CB receptors were significantly increased in mouse liver infected with S. japonicum. The more damage in the hepatocytes the more expression of CB receptors. There was much expression of CB2 receptor in the immunocytes around the worm tubercules of S. japonicum. So we concluded that the endogenous cannabinoids may participate in liver fibrogenesis and portal hypertension in mouse liver fibrosis infected with S. japonicum.