Effect of splenectomy on TGF-β1 and α-SMA expressions in the liver of rats with hepatic fibrosis
Objective: To study the influence of splenectomy on development of hepatic fibrosis through observation of the changes in mRNA expressions of TGF-β1 and α-SMA in liver tissue after splenectomy performed at different time periods in rats with hepatic fibrosis. Methods: Fifty male SD rats were randomly allocated into normal control group, liver fibrosis model group (model group) and liver fibrosis model with splenectomy group (splenectomy group). The liver fibrosis model was induced by intraperitoneal injection of 40% CCl4, and rats in splenectomy group underwent splenectomy at early stage (2 weeks), mid stage (4 weeks) and late stage (6 weeks) after model induction in batches, respectively. All rats were sacrificed at 8 weeks after model induction, the pathological changes in the liver tissues were evaluated by HE staining, and the mRNA expression levels of TGF-β1 and α-SMA in the liver tissues were determined by qRT-PCR method. Results: The structure of hepatic lobules was intact in normal control group, while in model group, it was destroyed with fibrous tissue hyperplasia and pseudo-lobule formation; pathological changes of hepatic fibrosis of different degrees were found in all splenectomy groups, which presented with increasing severity with the lag of time of splenectomy, but all were milder than that in model group. The results of qRT-PCR showed that compared with normal control group, the mRNA expression levels of both TGF-β1 and α-SMA in all other groups were significantly increased (all P<0.05), and the increasing degrees in both factors were presented as follows: model group > late-stage splenectomy group > mid-stage splenectomy group > early-stage splenectomy group (all P<0.05). Conclusion: Splenectomy can reduce the expression levels of TGF-β1 and α-SMA in liver tissue, which suggests that the spleen may be involved in the occurrence and developent of liver fibrosis.