Effect of long-time mechanical ventilation on early postoperative inflammatory responses in hipp-ocampi of mice / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of long?time mechanical ventilation on early postoper?ative inflammatory responses in the hippocampi of mice. Methods Forty?eight healthy male C57BL∕6 mice, aged 8-10 weeks, weighing 20-25 g, were divided into 3 groups ( n=16 each) using a random number table control group ( group C) , operation group ( group O) and long?time mechanical ventilation after operation group ( group MV) . Open reduction and internal fixation was performed after tibial fracture was induced in O and MV groups. Group O inhaled isoflurane for 6 h after operation. The mice were me?chanically ventilated for 6 h under isoflurane anesthesia in group MV. On 1 and 3 days after the end of ven?tilation, 8 mice were randomly selected, and contextual fear conditioning test was carried out to assess the cognitive function. The rate of time spent freezing was calculated. Then venous blood samples were collected and hippocampi removed for determination of the levels of interleukin?6 ( IL?6) , tumor necrosis factor?al?pha ( TNF?α) and IL?1β in plasma and hippocampal tissues by enzyme?linked immunosorbent assay. Re?sults Compared with group C, the rate of time spent freezing was significantly decreased, and the levels of IL?6, TNF?α and IL?1β in plasma and hippocampal tissues were significantly increased after the end of ventilation in group O ( P<0.01) . Compared with group O, the rate of time spent freezing was significantly decreased, and the levels of IL?6, TNF?α and IL?1β in plasma and hippocampal tissues were significantly increased after the end of ventilation in group MV ( P<0.01) . Conclusion The mechanism by which long?time mechanical ventilation leads to early postoperative cognitive dysfunction is related to induction of in?flammatory responses in the hippocampi of mice.