^(60)Co γ射线放射后大鼠腮腺细胞自噬初步观察

Preliminary observation of autophagy in rat parotid gland cells following ^(60)Co γ radiation

目的:观察^(60)Co γ放射对腮腺细胞自噬的影响及探讨放射后腮腺细胞自噬与凋亡的关系。方法:54只SD大鼠随机分为9组(n=6);对照组、6 Gy及12 Gy放射组各3组。以^(60)Co γ射线对大鼠头颈部进行放射,一次性给予放射剂量。分别于放射后12、24、48 h收集腮腺标本。透射电镜观察细胞自噬及凋亡,免疫组化SABC技术检测Bcl-2、Bax、Beclin1、LC3蛋白表达。结果:正常腮腺细胞与放射后腮腺细胞中均可见自噬体、自噬溶酶体。凋亡细胞中存在自噬体和自噬溶酶体。各放射组自噬阳性率及Beclin1、LC3蛋白表达水平无明显变化(P>0.05);放射组细胞凋亡率显著提高,Bcl-2表达水平下降,Bax表达水平上升(P<0.05)。结论:^(60)Co γ射线可以激活腮腺细胞凋亡,对腮腺细胞自噬的影响可能是微弱的。

Objective： To investigate the effects of ^60Coγ radiation on the autophagy of parotid gland cells and the relationship between autophagy and apoptosis of the cells after radiation. Methods ： 54 male aduh SD rats were randomly divided into 9 groups （ n = 6 ）. The rats in 3 control groups were not exposed to radiation, in 3 groups received a single 6-Gy dose radiation, and in other 3 groups received a single 12 Gy dose radiation. At 12, 24 and 48 h after radiation, parotid gland tissues were respectively collected. The autophagy and apoptosis of the cells were observed by transmission electron microscope. These levels of Bcl-2, Bax, Beclinl and LC3 protein were evaluated with pathological image and immunohistochemical SABC assay. Results： Autophagosome and autolysosome were visible in parotid gland cells of all groups. Autophagosome and autolysosome existed in apoptotic ceils. Compared with all control groups, the autophagy positive rates of radiation groups did not increase or decrease（P 〉0.05）. In radiation groups the apoptotic rate increased（ P 〈 0. 05 ）, Bcl-2 protein decreased and Bax protein increased compared with those in all control groups （P 〈 0.05 ）. The expression of Beclinl and LC3 protein in treatment groups were not statistically different from that in control groups（P 〉 0.05）. Conclusion： ^60Coγ rays can activate the apoptosis of parotid gland cells, but the effect of ^60Coγ ray on the autophagy of the cells may be weak.