Changes in rats splenic macrophage during the process of live cancer induced by diethylnitrosamine

Abstract

Objective Background It generally accepted that spleen played complex role in the tumor immunity,which would change in the different periods of cancer. In this study, we investigate the changes in the functions of splenic macrophage (Mtp) in different stages of liver cancer induced by dieth- ylnitrosamine (DEN) in rats, to support the characteristics of two-way and phase of spleen in antitu-mor immunity. Methods Establishing the mode of pulmonary metastasis of liver cancer in forty male SD rat by diethylnitrosamine. In the 8th, 13 th and 16th week, 10 rats were randomly chosen and sacrificed, and divided into cirrhosis,liver cancer and pulmonary metastasis group depending on the pathology result, re-spectively. The other 10 rat were taken as control group. The Mω was isolated by anchoring cultivation. The changes in ultrastructure, phagocytosis, eytokine secretion, antigen processing and presenting, and viability of splenic Mω were detected by transmission electron microscope, VybrantTM Phagoeytosis Assay, DQTM Ovalbumin ,and httman TNF-α ELISpot kits. Results Under the electron microscope,the Mω in the control group had some prominences like pseudopodium, and mitochondria, ribosome, rough endoplasmic reticulum, lysosome can be found in the cytoplasm, and RBC phagocytosed. In the liver cirrhosis and liver cancer group, Mω had more prominences, meanwhile much more mitochondria, ribosome, rough endoplasmic retic-ulum, lysosome can be found in the cytoplasm, especially the liver cancer group. What is more, we can see the macrophage that is phagocytoseing or had phagocytosed other apoptosis and necrosis cells. In the pul- monary metastasis group,the Mω was swelling, with few organelle. As compared to the control group, thefunction of splenic Mω increased in cirrhosis and cancer group,but decreased in metastasis group (phago-cytosis rate:84.7±1.9,89.5±3.1 and 36.0±2.6 vs 75.6±1.7,P <0.05,P <0.01 ;viability: 1.53± 0. 15,1.56±0.14,and 1.12±0. 29 vs 1.48±0. 17, P < 0.05 ; TNF-α secretion: 741.0±52.9,1126. 2± 174.5 ,and 313.8±50.8 vs 626.6±24.6 ,P <0.05 ,P <0.01 ;positive cell rate of antigen processing and presenting:24.03±1.87,27.95±2.63,and 10.46±2.16 vs 16.45±1.86,P<0.01 ). Conclusion In the stage of cirrhosis and early cancer, the immune functions of splenic Mω were reinforcement. It may pro-mote the non-specificity tumor immunity. On opposite, in the stage of pulmonary metastasis, the immune functions of splenic Mω were impaired. It may lead to the decrease of tumor immunity. Key words: Carcinoma,hepatocellular; Spleen; Macrophage