γ线引起小鼠骨髓造血细胞凋亡的定量病理研究

Quantitative pathologic studies for apoptosis of hemapoietic cells in irradiated mouse bone marrow

迄今，骨髓辐射损伤后造血细胞凋亡的病理研究很少，其定量变化规律更未见报道。本文采用６０Ｃｏγ射线照射ＬＡＣＡ小鼠，于照射后６小时、１天及３天分批活杀，将右股骨骨髓经３％戊二醛及１％锇酸固定，制作半薄切片、超薄切片，并用ＣａｍｂｒｉｄｇｅＱｕａｎｔｉｍｅｔ９７０型图像分析仪，定量研究了辐射诱导的骨髓造血细胞凋亡的形态特征及其与照射剂量之间的关系。结果表明：对照组动物骨髓仅有少数造血细胞凋亡，而照射后６小时各剂量组动物骨髓内发生凋亡的造血细胞均明显增多，病理特点为：凋亡早期见核染色质浓缩、边移，呈半月形、环形或不规则形；中期见大小不等，形状不一的染色质团块周围有核膜包绕，核碎片形成；晚期见凋亡小体形成，可游离于细胞间或被邻近细胞吞噬。定量分析示各照射组动物凋亡的骨髓造血细胞的数密度和面密度均明显增加，与对照组比，其差异显著（Ｐ＜００１）。且剂量越大，凋亡细胞的数密度和面密度越大。最后，本文作者根据实验结果指出：凋亡是辐射介导的骨髓造血细胞死亡的主要死亡方式。本研究为急性放射病的诊治提供直接依据，亦可能对其他原因引起的细胞凋亡的研究具有参考意义。

So far there have rarely been reported on apoptosis of hemapoietic cells in bone marrow after radiation, let alone, its quantitative pathologic studies. 78 LACA mice were irradiated with doses of 2 5, 4 0, 5 5 and 7 0 Gy 7-rays, and sacrificed at 6 hours, 1 day and 3 days after radiation respectively. Bone marrow of right femur was removed and fixed in 3% glutaraldehyde and 1% OsO 4 and embedded in spurr s resin. Semi-thin and thin sections were made and observed by LM and EM. The number and area densities of apoptotic cells were also detected by means of Cambridge Quantimet 970 image morphometry. The results showed: There were only few hemapoietic cells with apoptosis in control mouse bone marrow, whereas 6 hours after radiation much more apoptotic hemapoietic cells were found in each irradiated group bone marrow. Furthermore, the higher radiation dose was, the more apoptotic cells were. The characteristics of apoptotic cells were the chromation became pyknotic and packed into smooth masses and wrapped with nuclear membrane (margination of chromatin), just as semiluner ring-like or irregular shapes. The nucleus may also break up (karyorhexis) and became apoptotic bodies, which may be phagocytized by macrophage or neighboring cells or remain free. The results of quantitative analysis showed both number and area densities of the bone marrow cells obviously increased in every radiation groups, compared with the controls (P<0 01), and the higher radiation dose was, the more number and area desities were. Finaly, the authors pointed out that apoptosis is the main death mode for radiation-induced hemapoietic cell death. These results filled an important material in this domain. And this phenomenon offers a direct evidence for the dignosis and treatment of acute radiatin sickness and may give the reference significance to the studies of apoptosis. induced by other reasons.