bax及bcl－2基因表达在γ线照后小鼠骨髓造血细胞凋亡及修复中的定量变化及意义探讨

Quantitative changes and significance of bax and bcl-2 expression in radiation-induced apoptosis of hematopoietic cells

至今，在国内外同类文献中，尚未见到采用免疫细胞化学技术研究ｂａｘ及ｂｃ１－２基因表达在辐射诱导的骨髓造血细胞凋亡及修复中的改变，其定量研究更未见报道。本文采用６０Ｃｏγ射线以２５—７０Ｇｙ剂量全射照射２１３只ＬＡＣＡ小鼠，动物于照射后６小时、１、３、６、１０、１５、２１天及４周分批活杀，将骨髓组织进行Ｈｅｌｙ’ｓ液或３％戊二醛和１％锇酸固定，制作光镜及电镜标本；同时对骨髓细胞涂片采用ＬＳＡＢ免疫细胞化学法进行Ｂａｘ及Ｂｃ１－２蛋白染色，并结合图像分析，研究了辐射诱导的造血细胞凋亡的规律及Ｂａｘ及Ｂｃｌ－２蛋白的定量变化及意义。结果表明：在照射剂量范围内，骨髓出现明显损伤及损伤后重建现象，其病理特点分为造血细胞减少期、骨髓空虚期、再生基本恢复期及基本恢复期四个阶段。在照后６小时，各剂量组骨髓造血细胞出现凋亡的形态改变，表现为核染色质浓缩、边移，呈半月型、环形或不规则状；可见凋亡小体，或游离或被邻近细胞吞噬。ｂａｘ基因于照后６小时（恢复造血细胞减少期）表达明显增多，而ｂｃｌ－２基因表达于照后１５天（再生恢复期）明显增多，表现为积分光密度及数密度增加，与对照组比，其差异显著，有统计学意义。表明ｂａｘ基因过量表?

Abstract There has not been reported on bax and bcl-2 expression in radiation-induced apoptosis of hematopoietic cells by means of immunocytochemistry, let alone quantitative research. 213 LACA mice were irradiated with a dose of 2.5, 4.0, 5.5 or 7.0 Gy γ-rays, sacrificed at 6 hours, 1,3,6,10,15,21 days and 4 weeks after radiation respectivly, and the bone marrow was fixed in Helly's solution or 3% glutaraldehyde and 1% OsO 4,made the specimens of LM and EM. At the same time, the bone marrow smears were stained with bax and Bcl-2 antibodies by means of the LSAB immunocytochemical method. In combination with image analysis, we studied the quantitative changes and significancc of bax and bcl-2 expression in radiation-induced apoptosis of hematopoietic cells. The results showed the bone marrow appeared to be obviously injured and reconstructed after radiation, and its characteristics of pathologic changes were divided into four phases, namely the injury phase,void