Effect of obesity factor on ventilator-induced lung injury in rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the obesity factor on ventilator-induced lung injury (VILI) in rats.Methods:Forty-five clean-grade male Sprague-Dawley rats, aged 6-8 weeks, were divided into 3 groups ( n = 15 each)according to the body weight normal weight control group (group C), normal weight VILI group (group CV) and obese VILI group (group FV). The body weight was 233-267 g in C and CV groups and 288-332 g in FV group.In group C, the tidal volume (V T) was 10 ml/kg.In CV and FV groups, the rats were ventilated for 4 h with the V T set at 40 ml/kg, respiratory rate 40 breaths/min, inspiratory/expiratory ratio 1∶2, PEEP 0 mmHg, and fraction of inspired oxygen 21% to establish the VILI model.The arterial blood samples were collected immediately before tracheal intubation and at 4 h of mechanical ventilation for blood gas analysis and PaO 2 recording.The remaining blood samples were used for plasma collection.The rats were sacrificed after blood collection at 4 h of ventilation, and the bilateral lung tissues were isolated to collect the bronchoalveolar lavage fluid (BALF). The concentrations of leptin in plasma and tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) in plasma and BALF were detected by enzyme-linked immunosorbent assay.The wet/dry weight (W/D) ratio of lung tissues was measured.The pathological changes of lung tissues were observed after HE staining, and the lung injury score was evaluated.The expression of NF-κB p65 in lung tissues was detected by Western blot. Results:Compared with group C and group CV, the plasma leptin concentration was significantly increased in group FV( P<0.01). Compared with group C, the concentrations of TNF-α, IL-6 and IL-1β in plasma and BALF were significantly increased, PaO 2 was decreased, the lung injury score and W/D ratio of lung tissues were increased, and NF-κB p65 expression was up-regulated at 4 h of ventilation in CV and FV groups ( P<0.01). Compared with group CV, the concentrations of TNF-α, IL-6 and IL-1β in plasma and BALF were significantly decreased, PaO 2 was increased, the lung injury score and W/D ratio of lung tissues were decreased, and NF-κB p65 expression was down-regulated at 4 h of ventilation in group FV ( P<0.05). Conclusion:Obesity factor can reduce VILI in rats, and the mechanism may be related to the increase in plasma leptin levels.