人类胚胎胸腺细胞凋亡的定量研究

THE QUANTITATIVE STUDY ON APOPTOTIC THYMOCYTES OF THE HUMAN EMBRYONIC THYMUS

用５３例人类胚胎胸腺标本对胸腺细胞在发育过程中的凋亡现象进行了定量研究。结果显示，８周时开始出现胸腺细胞，１１周时腺实质开始区分出皮质和髓质。此后，皮质内正常胸腺细胞的量始终明显多于髓质，而凋亡胸腺细胞的量却明显少于髓质。不同发育阶段的胸腺细胞凋亡率，在皮质变化较小，波动于１．４％～４．７％之间；在髓质则变化较大，波动于６．５％～７４％之间，其峰值出现于１７～２２周。表明胸腺细胞的凋亡主要发生在髓质，而且具有明显的阶段性。

The apoptotic process of thymocytes of the human embryonic thymus was studied with 53 specimens.The results are as follows:the thymocytes begin to appear at 8 weeks of gestation;the cortex and medulla can be distinguished at 11 weeks.Afterwards the normal thymocytes in the cortex are much more than those in the medulla,but the apoptotic thymocytes in the cortex are much fewer than those in the medulla.With the developing process,the apoptotic rate of the thymocytes in the cortex varies from 1.4% to 4.7%,showing a little fluctuation,but on the contrary,that in the medulla varies from 6.5% to 74%,showing a large fluctuation and a peak value during 17￣22 weeks.These results revealed that in the developing thymus the apoptosis of the thymocytes takes place mainly in the medulla and varies with the devolopment stages.