手术应激对成年和婴幼鼠吞噬受体表达及其细菌杀灭能力的影响

Effect of surgical stress on the expression of phagocytic receptors and the bactericidal activity in adult and infant mice

目的吞噬作用是宿主固有免疫抵御外来入侵病原微生物的一个关键因素。手术应激可产生机体免疫抑制，增加感染的危险。本研究旨在探讨手术应激对成年鼠和婴幼鼠吞噬受体表达及其细菌杀灭能力的影响，分析吞噬体成熟及杀菌机制，进而为临床干预提供依据。方法取婴幼（1～2周龄）和成年（8-10周龄）Balb／C小鼠各40只，分为对照组和手术应激组。腹腔灌洗法分别取术后24h和对照组腹腔巨噬细胞，流式细胞仪测定巨噬细胞表面吞噬受体FcyR和CR3的表达；巨噬细胞与活菌共同孵育不同时间，计数细菌菌落生长数，计算胞内细菌杀灭数。结果经流式细胞仪测定，对照组婴幼鼠巨噬细胞吞噬受体CR3和FcyR荧光强度分别为261．77±22．75和38．42±4．29，较对照组成年鼠（453．33±23．80、43．07±12．01）表达低（P〈0．05）；手术应激后，婴幼鼠表达（49．87±3．04、9．57±0．76）明显下降（P〈0．05），而成年鼠表达（263．00±9．33、45．43±1．98）下降不明显。与细菌共培养30min和60min后，细菌吞噬率分别为43．750o±4．70％和61．29％±10．94％，较成年鼠（58．34％±8．87％和76．02％±3．64％）低（P〈0.05），手术应激后，婴幼鼠细菌吞噬率（38．06％±12．90％和56．15％±11．00oA）亦有所下降。结论婴幼鼠较成年鼠吞噬受体表达低，细菌杀灭能力弱。手术应激后，婴幼鼠吞噬受体的表达进一步降低，吞噬功能明显受损，细菌杀灭能力进一步下降，从而增加了术后感染的风险。

Objective Phagocytosis is a key element of the host innate immune system to fight against microbial pathogens. Macrophages detect pathogens through several phagocytic receptors such as Fc7 receptors and complement receptors. The combination of receptors and pathogens activates various intracellular signal transduction pathways. Surgical stress will cause immune suppression and increases the risk of infections postoperatively. Our research was to investigate the effect of surgical stress on the expression of phagocytic receptors and the bactericidal activity in a mice model. Methods Infant （aged 1-2 weeks） and adults （aged 8-10 weeks） Balb/c mice were randomized to control and surgical stress group （n = 20）. Peritoneal lavage was collected from both groups 24hrs postoperatively. FACSean analysis was performed to detect the surface expression of CR3 and FcγR on macrophages, After co-culture of peritoneal macrophages and Escherichia coli for different time duration, the number of bacterial colony was counted, and the bactericidal ability of macrophages was calculated. Results The expression of phagocytic receptors CR3 and FcTR on the infant maerophage were lower than in the adult in the control group （P〈0. 05）. After surgical stress, the expressions of phagocytic receptors the infant macorphage were more downregulated than in the adult group （P〈0. 05）. The infant macrophage was weaker in the bactericidal activity after 30rain and 60rain co-incubation than in the adult. This was also reduced in infant macrophage after surgical stress. Conclusions The expression of phagocytic receptors on macrophages and the function of infant mice was lower and they are inefficient in killing bacteria. That may increase the risk of infections postoperatively.