Biological Characteristics Of Nude Rat And Its Use As Animal Tumor Model

In this study, we used nude rat, a kind of T cell immunodeficient rat, as a animal model to analyze its biological characteristics and to explore the application in the research of hepatocellar carcinoma (Huh—7).The rnu/rnu rats aged 0-30w were used in periodical weight, growth curve and breeding character (primiparity days, little number) measurement, while rats aged 8w were used in the weights measurement of viscera and hematological & blood biochemical parameters examination by biochemical analyzer. Its average little number was 13.2±0.6 and survival rate was 50%.The average interval between two little was 40.3±7.6. The earliest birth was 89-day-age and the longest was 156-day-age, mostly in 92～105 days age which occupied 45 percent of all the pairs. Weight of rnu/rnu rat increased relate to its age before 18 weeks, then the weight increased relatively and reached the platform of body weight in the later stage. The increasing rate of weight of male rnu/rnu rats were higher than the rate of their female littermate. The weight of male and female rnu/rnu rats were 365.5851±12.3621g and 268.2178±12.4128g respectively at 30w age. It showed that there are no abnormalities in position, appearance, and histological structure of organs such heart, liver, spleen, kidney and lung. About 20% some female rnu/rnu rats had the ovays with abnormal appearance or partial histological structure loss. Significant differences were found in related organ weight and index between the male and female rnu/rnu rat. Moreover, there were significant gender-related differences in the level HCT, CHE, Na, HGB, TBA. However, no significant difference were found in classification of lymphocyte between male and female.We established a metastatic animal model of hepatocellar carcinoma by orthotopic and subcutaneous transplantation of Huh-7 cell line onto rnu/rnu rat,. The growth of tumor was superior to that of nude mice. In orthotopic transplant model of rnu/rnu rat, tumor formation rate was 95.5% and metastasis rate of liver, lymph node and midriff were 100%, 72.6% and 17.8% respectively, significantly higher than that in nude mice. Tumorgenecity, invasion, metastasis and morphological characteristics of the implanted tumors were studied by light microscopy, electron microscopy and flow cytometry. The result showed that orthotopic transplant rumor animal model of rnu/rnu rat had basically reproduced the clinical course of hepatocellar carcinoma, and the replication and especially the metastasis of Huh-7 in rnu/rnu rat 1 was better than that in nude mice which should be valuable for research on mechanism and new therapies for metastasis.