The Influence Of Hot And Cold On Biological Features Of Rat Hepatic Cancer Model Induced By DEN

Object:To investigate the effects of various cold or heat stimuli on the tumor biological features,including the formation,proliferation and metastasis of tumor,in the DEN induced hepatic carcinoma rats by means of setting appropriate temperature as the cold and heat stimuli,and to determine the possible immunological mechanisms.Method:(1) Setting of environmental temperature:thirty male Wistar rats were randomly divided into blank control group and cold-heat stimulating groups;set the environmental temperature to 40℃,36℃,-4℃or 0℃for the corresponding cold-heat stimulating group,and maintained it for 3 hours per day for four weeks,whereas maintained the environmental temperature at 22℃for the control group.And then their mode of life was observed.(2) Forty-two male Wistar rats were randomly divided by weight into blank control group(N,n=6),model group(G1,n=12),heat stimulating group(G2,n=12) and cold stimulating group(G3,n=12).The rats in the G1,G2 and G3 group were treated with 0.2% DEN(10mg/kg) through intragastric administration,once per day,5 times per week for 14 weeks,while those in the N group were treated with the same amount of saline.Kept the G2 group under the heat environment(36±2)℃,the G3 group under the cold environment (0±2)℃for three hours per day,and five times per week for twenty weeks.Sacrificed the rats at the end of the 20th week,observed the morphologic changes of the livers and the serum,liver and lung biopsy samples were collected.(3) HE stained liver samples were used to observe the inflammatory reaction which was graded by the Edmondson standard.(4) The liver function tests,which were consisted of alanine aminotransferase(ALT), aspartate aminotransferase(AST),albumin(ALB) and y-Glutamyltranwferase (gamma-GT),were made using automatic biochemical analyzer.(5)Vascular endothelial growth factor(VEGF),proliferating cell nuclear antigen(PCNA) and Kiel 67 antigen(Ki-67) expressions of the tumor tissue were examined by immonohistochemistry technology.(6) Serum IL-2,IL-4,IL-10 and IFN-γlevels were measured by ELISA.Result:(1) General state of the rats:before the model making of the rats,there was no significant difference among the groups in weight;but after the forming of the model,the weights of all those who underwent the stimuli were obviously decreased when compared to the N group(P<0.05),while there was no statistically significant difference in weights among the G1,G2 and G3 groups(P>0.05);the death rates of the G1,G2,G3 and N groups were 16.67%(2/12),33.33%(4/12),16.67%(2/12) and 0%(0/6) respectively.(2) Liver function:the serum ALT,AST,ALB andγ-GT levels of the G1,G2 and G3 groups increased obviously when compared to those of the N group;the liver function of the G3 was better than those of the Gl and G2,while that of the G2 was worse than the G1.(3) Indicators for carcinoma formation:the HE stained liver pathologic slices of those in the G1,G2,G3 group showed carcinoma nodules and hepatic cirrhosis;judging by the Edmondson standard,the lesions of the G2 group were apparently worse than those of the G1 and G3 groups;the immonohistochemical results suggested low-leveled VEGF expression in the N group,while those of the G1,G2,G3 group were significantly higher, when compared to the G1 group,those of the G2 were higher,but the G1 group were lower.(4) Indicators for carcinoma proliferation:the immonohistochemical results suggested low-leveled Ki-67 and PCNA expression in the N group,while those of the G1,G2,G3 groups were significantly higher,when compared to the G1 group,those of the G2 group were higher,but the G1 group were lower.(5) Indicators for carcinoma metastasis:when the rats were sacrificed,pulmonary metastasis were found in those of the G1,G2 and G3 group,and the pulmonary metastasis rates of the G1,G2,G3 and N groups were 25.0%(3/12),41.67%(5/12),16.67%(2/12) and 0%(0/6) respectively.(6) Immunological indicators:spleen index calculating results suggested that those of the G1,G2 and G3 groups were obviously higher as compared with the N group;the G2 and G3 groups were significantly different with the sequence of G2>G1>G3;ELISA results of the G1,G2 and G3 groups indicated immunological imbalance,specifically,the serum IL-2 and IFN-γlevels decreased while the serum IL-4 and IL-10 levels increased when compared to the N group,with the sequence of G2>G1>G3.Conclusion:(1) Long term(20 weeks) cold or heat stimuli[(0±2)℃,(36±2)℃]can induce effects of different degree on rats.(2) Long term cold stimuli with(0±2)℃have some inhibitory,effects on the formation,proliferation and metastasis of the carcinoma,while the heat stimuli with(36±2)℃promoted them.(3) The effects on the immunologic function and the Th1/Th2 drift may be the possible mechanisms for the changing of the biological features due to the cold or heat stimuli.