Qiao S, Nagasaka T, Harada T, Nakashima N
Department of Laboratory Medicine, Nagoya University School of Medicine, Japan.
Placenta. 1998 Jul-Aug;19(5-6):361-9. doi: 10.1016/s0143-4004(98)90075-3.
This study investigates the extent of apoptosis in complete hydatidiform mole (CHM), using an in situ 3'-end DNA labelling (TUNEL) technique on formalin-fixed and paraffin-embedded sections. The sections were also immunostained with antibodies to p53, Bax and Bcl-2 proteins. In 10 normal placenta cases and 15 CHM cases, the apoptotic index was <1 and 2-4 per cent, respectively. The labelled trophoblastic cells possessed pyknotic nuclei and densely eosinophilic cytoplasm which corresponded well to the so-called apoptotic bodies by light and electron microscopy. The p53 positive reaction was restricted to the nuclei of cytotrophoblasts and intermediate trophoblasts, while the syncytiotrophoblasts showed only rare immunolocalization. Strong p53 expression was seen most often in cytotrophoblasts of CHM (>30 per cent of nuclei) which also showed a higher apoptosis index, while cytotrophoblasts in normal placentae were weakly and focally labelled (<10 per cent of nuclei). There were statistical differences between normal and CHM cases (P<0.05). Bcl-2 accumulation, on the other hand, was observed predominantly in syncytiotrophoblasts of normal placentae, and cytotrophoblasts and intermediate trophoblasts did not express Bcl-2 in all cases. Interestingly, syncytiotrophoblasts were found to be negative for Bax protein and positive in cytotrophoblast, which is consistent with the function of the protein in conveying increased apoptosis susceptibility to this cell population. The results show that the level of apoptosis correlates with the histological type of the gestational trophoblasts, and apoptosis index is higher in cytotrophoblasts in CHM. The fact that p53 quantitative expression and an increase in the Bax/Bcl-2 ratio were also observed in CHM suggested that they may contribute partly to the high level of apoptosis.
本研究采用原位3'-末端DNA标记（TUNEL）技术，对福尔马林固定、石蜡包埋切片进行检测，以研究完全性葡萄胎（CHM）中的凋亡程度。切片还用p53、Bax和Bcl-2蛋白抗体进行免疫染色。在10例正常胎盘病例和15例CHM病例中，凋亡指数分别<1%和2%-4%。标记的滋养层细胞具有固缩核和嗜酸性致密细胞质，通过光镜和电镜观察，这与所谓的凋亡小体非常吻合。p53阳性反应局限于细胞滋养层和中间滋养层的细胞核，而合体滋养层仅显示罕见的免疫定位。在CHM的细胞滋养层中最常观察到强p53表达（>30%的细胞核），其凋亡指数也较高，而正常胎盘中的细胞滋养层呈弱局灶性标记（<10%的细胞核）。正常病例和CHM病例之间存在统计学差异（P<0.05）。另一方面，Bcl-2的积累主要在正常胎盘的合体滋养层中观察到，并且在所有病例中细胞滋养层和中间滋养层均不表达Bcl-2。有趣的是，发现合体滋养层Bax蛋白呈阴性，而细胞滋养层呈阳性，这与该蛋白在使该细胞群体增加凋亡易感性方面的功能一致。结果表明，凋亡水平与妊娠滋养层的组织学类型相关，CHM中细胞滋养层的凋亡指数更高。在CHM中还观察到p53定量表达以及Bax/Bcl-2比值增加，这一事实表明它们可能部分导致了高水平的凋亡。
