大剂量内毒素（ＬＰＳ）可引起成年雄性小鼠胸腺严重萎缩，胸腺细胞大量凋亡。但对ＬＰＳ耐受动物的胸腺重量、胸腺指数、胸腺细胞总数及活细胞数均明显高于非耐受组，且胸腺细胞ＤＮＡ断裂少，电泳未见凋亡细胞特有的“梯状”ＤＮＡ碎片出现。表明耐受内毒大的动物其胸腺细胞凋亡亦呈现耐受性。 Large dose of endotoxin (LPS) can cause severe thymus atrophy in adult male mice, thymus apoptosis in large numbers. However, the thymus weight, thymus index, total thymocytes and viable cells in LPS-tolerant animals were significantly higher than those in non-tolerant groups, and DNA fragmentation in thymocytes was small. There was no “ladder” DNA fragment characteristic of apoptotic cells in electrophoresis appear. The animals that tolerated large endotoxemia also showed thymocyte apoptosis.