Effect of splenectomy on inducible nitric oxide synthase expression and microvessal density in implanted hepatic tumor model of prehepatic portal hypertension rats

Abstract

Objective To evaluate the role of splenectomy in inducible nitric oxide synthase (iNOS) expression and microvessal density (MVD) in implanted hepatic tumor model of prehepatic portal hypertension rats. Methods The prehepatic portal hypertension rats were divided randomly into two groups: The rats in group A were subjected to splenectomy one week before implantation of tumor tissues; the rats in group B were not subjected to spleuectomy but sham operation one week before implantation of tumor tissues. Walker-256 tumor tissues were implanted in livers of group A and group B. Two weeks after tumor tissue implantation, the samples of tumor tissue were harvested. The expression of iNOS mRNA in two groups was detected by reverse transcription pelymerase chain reaction. MVD was counted by irnmunohistochem-istric staining with CD34 antibody. The volumes of tumor were measure by vernier caliper. Results In group B the iNOS expression was elevated significantly in eomparision with group A (P 0.05). Conclnsion After splenectomy, the expression of iNOS in the implanted hepatic tumor in prehepatic portal hypertension rats was decreased in comparison with that not subject to splenectomy. The lower expression of iNOS could lead to the lower products of NO, which reduced the stimulators in tumor angiogenesis, resulting in the decrease of MVD in tumor tissue. Spleuectomy on prehepatic portal hypertension rats can decrease the invasive abilities of malignant hepatic tumor. Key words: Splenectomy; Inducible nitric oxide synthase; Hepatic tumor; Portal hypertension