大鼠自发性乳腺肿瘤中Bax、Bcl-2和Caspase-3的表达

Expression of Bax,Bcl-2 and Caspase-3 in spontaneous mammary gland tumors of rats

通过130只(雌雄对半)Sprague-Dawley(SD)大鼠进行自发性乳腺肿瘤造模,并研究自发产生的乳腺肿瘤组织的病理变化及B细胞淋巴瘤/白血病-2(B cell lymphoma/leukmia-2,Bcl-2)、B细胞淋巴瘤/白血病-2相关X蛋白(B cell lymphoma/leukmia-2 associated X protein,Bax)和含半胱氨酸的天冬氨酸蛋白水解酶-3(cysteinyl aspartate specific proteinase-3,Caspase-3)在乳腺肿瘤中的蛋白和m RNA表达变化。造模结果显示共有14只雌性大鼠发生乳腺肿瘤,对总体而言肿瘤的发病率为10.77%(14/130);由于雄性大鼠未见乳腺肿瘤,在雌性大鼠中肿瘤的发病率为21.54%(14/65)。苏木精-伊红(hematoxylin-eosin,HE)染色病理切片观察确定肿瘤分型分别为乳腺纤维腺瘤7例,乳腺腺癌3例,乳腺乳头状癌2例,乳腺浸润性导管癌2例。免疫组织化学(immunohistochemistry,IHC)结果显示,对照组(n=5)Bax、Bcl-2和Caspase-3的蛋白表达量分别为9.75±0.04、8.13±0.35和6.60±0.04,而这3个因子在良性病变组(n=7)的蛋白表达量分别为8.16±0.16、9.14±0.22和4.43±0.1。另外,其在恶性病变组(n=7)的蛋白表达量分别为6.49±0.32、9.24±0.81和3.03±0.10,与对照组相比,Bax和Caspase-3在病变组的表达极显著减少(P<0.01),而Bcl-2在病变组中的表达与对照组相比也显著增加(P<0.05),且正常对照组Bcl-2/Bax比值小于1,而在良性组和恶性组则均大于1。荧光定量聚合酶链式反应(real-time fluorescence quantitative PCR,RTFQ-PCR)结果通过相对定量计算显示,Bax、Bcl-2和Caspase-3在各组中的m RNA的表达量变化与蛋白表达一致,相比差异有高度统计学意义(P<0.01)。综上所述,自发性乳腺肿瘤在雌性大鼠中的发病率较高,且病变类型多样,而雄性发病率为0;且Bcl-2、Bax和Caspase-3与大鼠自发性乳腺肿瘤的发生有着密切的联系,从而为临床乳腺肿瘤的诊断、治疗和预后提供了新的思考方向。

The investigation on the expression and interaction of Bax, Bcl-2 and Caspase-3 in the spontaneous mammary gland tumors of Sprague-Dawley （SD） rats was of great importance to provide a reference for the prevention and treatment of clinical mammary gland tumors. One hundred and thirty （half male and female） SD rats were dissected after feeding 60 weeks, then the tumors were collected for pathological observation, and to measure the protein expression of Bax, Bcl-2 and Caspase-3 by immunohistoehemistry （IHC）, and the mRNA expression of the above factors were detected by real-time fluorescence quantitative PCR （RTFQ-PCR） method. Gross anatomy and pathology showed that 14 female rats had mammary gland tumors, the total incidence of tumors was 10. 77% （14/130）. However, in male rats, breast tumor had not been observed, meanwhile, the tumor occurrence rate in females was 21.54% （14/65）, including 7 cases of breast fibroadenoma, 3 cases of mammary adenocarcinoma, 2 cases of mammary papillary carcinoma, and 2 cases of mammary invasive ductal carcinoma, respectively. IHC results showed that in the control group （n=5）, the protein expression of Bax, Bcl-2 and Caspase-3 were 9.75±0. 04, 8. 13± 0. 35 and 6. 60±0. 04, respectively; in the benign group （n=7）, the protein expression levels of these three factors were 8.16±0. 16, 9.14±0.22 and 4. 43±0. 1, respectively, while in its malignant lesion group （n =7） were 6.49±0. 32, 9.24± 0. 81 and 3.03 ± 0. 10, respectively. In addition, compared with the control group, the expression of Bax and Caspase-3 was significantly reduced （P〈0.01） in the diseased groups, and the expression of Bcl-2 in lesion groups was significantly increased （P〈0. 05）. Moreover, in the control group, the Bcl-2/Bax ratio was less than 1, which was more than 1 in benign and malignant groups. Compared with the IHC results, the RTFQ-PCR results showed that the mRNA expression of above factors were consistent with the protein expression, also showed highly significance （P〈0.01）. It is concluded that female rats have a high incidence of mammary tumors, which was not observed in males; Bcl-2, Bax and Caspase-3 are closely related to spontaneous mammary gland tumor, which may provide a new idea for diagnosis, treatment and prognosis of clinical breast tumor.