Liman N, Alan E, Bayram G K, Gürbulak K
Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Erciyes, Kayseri, Turkey.
Reprod Domest Anim. 2013 Feb;48(1):33-45. doi: 10.1111/j.1439-0531.2012.02021.x. Epub 2012 Apr 4.
Apoptosis has been shown to be an important regulator of endometrium function. To clarify the regulation of apoptosis in the cat endometrium during the normal oestrus cycle, the expressions of the apoptosis-related proteins (Bcl-2 and Bax) and their correlation to the inhibitor of apoptosis protein Survivin were analysed using immunohistochemistry. The TUNEL technique (TdT-mediated dUTP nick end labelling) was also used to detect DNA fragmentation characteristic of apoptotic cells. The results demonstrated that TUNEL labelling is not effective for the detection of apoptosis in cat endometrium. Survivin was expressed in the luminal and glandular epithelial cells of cat endometrium during all phases of the oestrus cycle. Survivin was localized in both the cytoplasm and nuclei of superficial and deep uterine gland cells during the luteal phase, while only cytoplasmic staining was observed during the follicular and anoestrus phases. Bax immunoreactivity in the cytoplasm of luminal and glandular epithelial cells as well as the smooth muscle cells of blood vessels was weak in the anoestrus phase. Compared with anoestrus, the intensity of Bax immunostaining was moderate in the follicular phase and increased dramatically in the luteal phase. Bcl-2 immunostaining in the cytoplasm of luminal and glandular epithelial cells was moderate in the anoestrus phase. During the early follicular phase, cytoplasmic Bcl-2 immunostaining was detected mostly in glandular epithelial cells. In the mid-follicular phase, in glands, the amount of Bcl-2 protein increased progressively from the superficial to the deep layer. In contrast, the expression of Bcl-2 decreased in the secretory phase, being very low or absent in the mid- and late luteal phases. The overall results suggest that Survivin, Bax and Bcl-2 proteins may cooperatively contribute to cell apoptosis and cell proliferation in the cat uterus during the oestrus cycle.
细胞凋亡已被证明是子宫内膜功能的重要调节因子。为阐明正常发情周期中猫子宫内膜细胞凋亡的调控机制，采用免疫组织化学方法分析凋亡相关蛋白（Bcl-2和Bax）的表达及其与凋亡抑制蛋白Survivin的相关性。还运用TUNEL技术（TdT介导的dUTP缺口末端标记）检测凋亡细胞特有的DNA片段化。结果表明，TUNEL标记法对检测猫子宫内膜细胞凋亡无效。在发情周期的各个阶段，Survivin均在猫子宫内膜的腔上皮和腺上皮细胞中表达。在黄体期，Survivin定位于浅层和深层子宫腺细胞的细胞质和细胞核中，而在卵泡期和乏情期仅观察到细胞质染色。在乏情期，腔上皮和腺上皮细胞以及血管平滑肌细胞细胞质中的Bax免疫反应较弱。与乏情期相比，卵泡期Bax免疫染色强度中等，在黄体期显著增加。在乏情期，腔上皮和腺上皮细胞细胞质中的Bcl-2免疫染色中等。在卵泡早期，细胞质Bcl-2免疫染色主要在腺上皮细胞中检测到。在卵泡中期，在腺体中，Bcl-2蛋白的含量从浅层到深层逐渐增加。相反，在分泌期Bcl-2的表达下降，在黄体中期和后期非常低或不存在。总体结果表明，Survivin、Bax和Bcl-2蛋白可能在发情周期中协同促进猫子宫中的细胞凋亡和细胞增殖。
