Analysis of non-neoplastic hepatic lesions in SD rats at different age / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the non-neoplastic hepatic lesions in SD rats at different ages. METHODS: The specificpathogen free SD rats were collected from the blank control groups used in subacute toxicity tests,subchronic toxicity tests and chronic toxicity combined with carcinogenic tests for safety evaluation. At the end of each experiment,i. e. week 10,19,56 and 108(assigned into four groups: 10,19,56 and 108 weeks,each contained 100 rats with each sex),rats were executed. The liver organ coefficient was calculated,the pathological examination was performed,and the non-tumorous lesions in the liver were analyzed. RESULTS: The liver organ coefficients at the age of 19,56,108 weeks were lower than that of 10 weeks(P < 0. 05); those at the age of 56 and 108 weeks were lower than that of 19 weeks(P < 0. 05),and that of 108 weeks was greater than of 56 weeks(P < 0. 05). Among the 10-week-old,19-week-old,56-week-old and 108-week-old groups,the types of non-neoplastic hepatic lesions detected in the female rats were 6,6,13 and 15 respectively,meanwhile those in the male rats were 6,6,13 and 15 respectively. Both male and female rats,the incidences of hepatocyte fatty degeneration,edema and hepatic infiltration of inflammatory cells were significantly increased with the increase of age in each group(P < 0. 05). The incidences of intrahepatic bile duct proliferation and intrahepatic bile duct fibrosis in rats at the age of 56 and 108 weeks were higher than those at the age of 10 and 19 weeks(P < 0. 008).Moreover,the frequency of hepatic sinus expansion lesions in rats at the age of 108 weeks was higher than those of 19 weeks(P < 0. 008). CONCLUSION: Spontaneous non-neoplastic lesions in the liver of SD rats were common,primarily demonstrated as hepatocyte fatty degeneration,edema and infiltration of inflammatory cells. The incidences of lesions increased with the increase of age.