Effect Of Splenectomy On Implanted Hepatic Tumor Rat Model With Portal Hypertension

Background and aimsHepatocellular carcinoma (HCC) is one of the most common malignancies worldwide,which is the fifth most prevalent cancer with a poor prognosis and the third most commoncause of death from cancer.80-90%of patients with HCC are associated with livercirrhosis. Cirrhosis is by far the most common cause of portal hypertension. There arekinds of treatment modalities for patients with HCC, such as hepatic resection, livertransplantation, transcatheter arterial chemoembolization, radiofrequency ablation,radiation therapy, biological therapy, traditional Chinese medical and multimodalitytherapy. Hepatic resection still remains the mainstream potential curative therapy in HCCpatients with well-preserved liver function. Historically, survival rates were35-62%at3years and17-50%at5years for patients with cirrhosis undergoing resection for HCC. Thepresence of liver cirrhosis is the most important risk factor for the development of HCC, as85-90%of HCCs arise in cirrhotic livers and30%are combined with hypersplenism inChina. Surgical treatment has been an effective therapy for HCC patients withhypersplenism in recent years in relation to improved surgical techniques andperi-operative management of patients. Spleen is the body’s largest peripheral lymphoidorgan, with cell immunity and humoral immune function, and plays an important role ofanti-inflammatory and antitumor in the immune response. Splenectomy in normal body,can lead to decreased immune function, cause acute fulminant infection, and evenundermine anti-cancer ability, especially in children. It is inconclusive whether the spleenhas immune function in HCC patients with portal hypertension. There is a debate onsplenectomy when hepatectomy is made in these patients. However, there are fewresearches on animal models.To evaluate the effect of splenectomy on progression of implanted hepatic tumor byestablishing implanted hepatic tumor rat model with portal hypertension.MethodsRat cirrhosis with portal hypertension models were built by subcutaneous injection ofcarbon tetrachloride (CCl4), and then the rats were randomly divided into two groups. Group A was subjected to splenectomy and implantation of Walker256tumor tissue on theleft lobe of liver, and group B was only subjected to implantation of tumor tissue.T-lymphocyte subsets CD4, CD8and CD4/CD8of two groups were examined10daysafter implantation of tumor tissue; the left lobe of liver was resected and the maximaltumor size was measured; expression of Ki67was detected by immunohistochemicalmethod in the tumor tissues. Continuous data were expressed as mean±standard deviationand were compared by t-test. P<0.05was considered statistically significant. All statisticalanalyses were performed with software package SPSS19.0(SPSS Inc, Chicago, IL).ResultsThe establishing of rat model of portal hypertension and the development of Walker256inrat were successful. There were42rat models of portal hypertension in all. The levels ofCD4and CD4/CD8in group A were higher than those in group B (0.36±0.01vs0.35±0.02,1.33±0.08vs1.24±0.05; P<0.05, P<0.01), and the level of CD8in group A was lower thanthat of CD8in group B (0.27±0.01vs0.29±0.02, P<0.01). There was no significantdifference in the maximal diameter of hepatic tumor between the two groups.Ki67-positive rate of tumor in group A was lower than that in group B (0.27±0.02vs0.28±0.02, P<0.05).ConclusionThe implanted hepatic tumor rat with portal hypertension built by subcutaneous injectionof CCl4can be used to model HCC patients with portal hypertension. Splenectomy in therat model can help to improve the immunity against hepatic tumor.