Why do anesthesia and surgical procedures deteriorate host defense ability in perioperative period?

本研究的目的是探讨外科手术患者产生宿主防御能力障碍的机制。研究结果如下：(1)手术后外周血中淋巴细胞数量减少。用流式细胞术将淋巴细胞分为辅助性T细胞(CD4)和抑制性T细胞(CD8)。上腹部手术后CD_4/CD_8比值(CD_4/CD_8)明显下降。(2)离心法分离淋巴细胞，在培养液中培养。然后用指示剂对核染色质进行染色。(3)在含有FAS抗体的培养液中孵育淋巴细胞，对标记细胞的比率进行分析，发现手术患者外周血中皮质醇、去甲肾上腺素、细胞因子等激素及细胞因子IL-I、TNF的含量明显升高。

The purpose of this study is to invetigate the mechanism by which host-defence inability has been produced in patients who underwent surgical treatment.The findings obtained are followed ; (1)The number of lymphcytes in periperal blood decreased after surgical procedures. The compositions of lymphocytes were separated into helper t-cells (CD4) and supressort-cells (CD8) by cyteflow metry. The ratio of CD4 and CD8 (CD4/CD8) decreased significantly after upper abdominal operations.(2) The lymphocytes were separated by centrifugation and cultured in a medium. Then the nuclear chromatin was stained by an indicator pigment. Microscopic examination revealed an increased fragmentation rate of nuclear chomatin in surgical patients.(3) The lymphocytes were incubated in a medium containing fas-antibody and the ratio of labelled cells were analysed, showing an increased staining in surgical patients.(4)The periphera bloods wete taken from postoperative patients to determine hormones such as cortisol and norepinephrine, and cytokines such as IL-I and TNF.The concentration of TNF in blood correlated very well to fragmentation rate of nuclear chromatin.Th results suggest that surgical invasion stimulate the destruction of peripheral lymphocytes by apoptotic process in postoperative perid.