亚急性低剂量铅暴露对大鼠细胞免疫功能的影响

为探讨亚急性低剂量铅暴露对大鼠细胞免疫功能的影响，将幼年ＳＤ大鼠分成６组，给予含不同剂量铅的饲料８周，观察铅暴露后大鼠血铅、Ｔ细胞亚群、血清肿瘤坏死因子（ＴＮＦ－α）和脾脏超微结构的变化。８周后各剂量铅暴露组血铅均高于正常对照组（Ｐ＜０．０１），并且随着铅剂量的增加而呈阶梯状升高。各铅暴露组Ｔ细胞亚群分布异常，ＣＤ４明显减少，ＣＤ４／ＣＤ８比例下降，ＣＤ８各组间差异显无显著性；血清ＴＮＦ－α分泌异

Effect of sub-acute low level exposure to lead on cellular immune function in rats

In order to observe the influence of low level exposure to lead on cellular immune functions in rats, sixty rats were randomly divided into six groups and were received diets with different levels of lead for eight weeks. Blood lead, serum tumor necrosis factor-alpha(TNF-alpha) level and the distribution of T lymphocyte subsets were measured. The pathological and ultrastructural changes of spleen were investigated. It was shown that lead exposure resulted in a significant increase of blood lead and decrease of the number of CD4 T-cells. But no significant difference was found in CD8 T-cell among all groups. Serum TNF-alpha at the lowest exposure group was significantly increased but that in other groups was lower than the control group. Electron microscopy for splenic immune cells indicated no significant difference between the lowest lead exposure group and the control group. The mitochondria of other groups were swollen, vaculated and pyknotic, endoplasmic reticulum were swollen and degranulated, nuclear chromatin were loosen. It was suggested that sub-acute exposure to lead, even at relative low exposure, would impair cell-mediated immunity and be harmful to spleen and thymus.