Expression of mitochondrial apoptotic pathway-related factors in Sprague-Dawley rats with spontaneous mammary neoplasms / 中国实验动物学报

ABSTRACT

Objective To investigate the expression of AIF, CYT C, PAF-1, caspase-3, and XIAP in Sprague-Dawley rats with spontaneous mammary neoplasms.Methods One-hundred and thirty 3-4-week old SPF Spargue-Dawley rats (♀∶♂=1∶1) were fed in a specific pathogen free (SPF) breeding barrier for 60 weeks.The occurrence of spontane-ous breast tumors was recorded and histopathology was performed to identify the types of tumors.The rats were divided into 3 groupsrats with normal breast tissue ( group I) , with benign tumors ( group II) and with malignant tumors ( group III) . The expression of AIF, CYT C, APAF-1, caspase-3 and XIAP proteins and mRNAs were detected by immunhistochemistry ( IHC) and RT-PCR assay.Results Among these 130 SD rats, 14 rats were observed having spontaneous mammary neo-plasms with the incidence rate of 10.77%(14/130).In these neoplasm cases, 7 cases were mammary fibroadenomas, 7 cases of breast carcinoma, both with an incidence rate of 5.38%.Immunohistochemistry showed that, compared with the group I, the positive expressions of AIF, APAF-1, caspase-3 were decreased significantly (P<0.01), and the CYT C and XIAP expressions were significantly increased in the group II.The positive expression of all genes except XIAP was de-creased in the group III(P<0.01).Compared with the group II, APAF-1 and XIAP were significantly higher in the group III (P<0.01), and the positive expression of AIF, Cyt C, and caspases-3 were significantly decreased (P<0.01).In the results of RT-PCR assay, except APAF-1 which showed significant correlation with the results of immunohistochemistry ( P<0.05 ) , all the others showed an extremely significant correlation with immunohistochemical results ( P <0.01 ) . Conclusions Mammary tumors are most common spontaneous neoplasms in SD rats.Abnormal expression of mitochondrial apoptotic pathway-related factors AIF, CytC, APAF-1, caspase-3, and XIAP are correlated with the carcinogenesis and de-velopment of breast tumors.