Effect Of Human Interleukin-10 On Ventilator-induced Lung Injury In Rats

Objective: To investigate the effect and the possible mechanism of human interleukin-10 pretreatment on Rats models of ventilator-induced lung injury.Methods: Thirty-six healthy male SD rats(weighing 220~300 g), were randomly assigned into 3 groups(n=12): the respiratory group(Control group), high tidal volume ventilation group(VILI group) and high tidal volume mechanical ventilation plus h IL-10 treatment group(h IL-10 group), Control group by endotracheal intubation after spontaneous breathing was maintained 4 hours; VILI group with high tidal volume mechanical ventilation(VT=30 ml/kg) to establish a rat model of VILI, atracurium infusion inhibits spontaneous breathing, maintain muscle relaxation, small animal ventilator mechanical ventilation, respiratory parameters: the respiratory rate of RR=40 / min, aeration time 4 h, respiratory ratio(I:E) =1:3, positive end expiratory pressure(PEEP) =0, Fi O2 =21%, tidal volume(VT) =30 ml/kg, according to the regulation of body weight VT; group h IL-10 mechanical ventilation before the start of 30 min from the tail vein injection of h IL-10(at a dose of 8000 U/kg), and others same with the VILI group, Control group and VILI group were given the same amount of saline. All the rats accepted laparotomy after ventilated for 4 hours, blood samples were obtained from abdominal aorta for arterial blood gas analysis, and calculate the oxygenation index(Pa O2/Fi O2); serum and bronchoalveolar lavage fluid(BALF) were collected to detect the density of tumor necrosis factor alpha(TNF-?)?interleukin-8(IL-8) and intercellular adhesion molecule-1(ICAM-1) by enzyme-linked immunosorbent assay(ELISA), the total protein content(TP) was detected by BCA. The right upper lung tissue was taken out for hematoxylin and eosin(HE) staining to observe the pathological changes of lung tissue and detect the expression of nuclear factor-kappa B p65(NF-?B p65)with immunohistochemistry; the right middle lung was dried to constant weight in a oven of 65 degrees Celsius to determine the lung wet-to-dry weight ratio(W/D); The right lower lobe of lung tissue was made into tissue homogenate, some of them were used to measure the level of extracellular signal regulated kinase-1(ERK1), p38 mitogen-activated protein kinase(p38 MAPK) and nuclear factor kappa-B p65(NF-?B p65) by protein Western blot and others were used to detect the content of MDA and the activity of SOD.Results:1 Pa O2/Fi O2?W/D: after mechanical ventilation for 4 hours, the Pa O2/Fi O2 of VILI group and h IL-10 group was significantly lower than Control group(P<0.05), the W/D was significantly higher than Control group(P<0.05); compared with VILI group, the Pa O2/Fi O2 of group h IL-10 increased significantly(P<0.05), the W/D decreased significantly(P<0.05).2 HE staining pathological changes: the optic microscope showed no obvious damage to the alveolar structure in Control group; compared with Control group,serious damage to the alveolar structure was observed in VILI group, the exudate in the pulmonary alveoli, interstitial edema and pneumorrhagia were observed obviously, visible fusion of the alveolar cavity, widened lung interval and lager number of inflammatory cells; compared with VILI group, the lung tissue of h IL-10 group has a certain degree of injury, thickened alveoli septum was also visible, but better than VILI group.3 The expression of NF-?B p65 by immunohistochemical: compared with Control group, the expression of NF- ? B p65 was increased in VILI group and h IL-10group(P<0.05); compared with VILI group, the expression of NF-?B p65 was decreased in h IL-10 group(P<0.05).4 The content of MDA? activity of SOD and TP in BALF: compared with Control group, the content of MDA and TP in BALF both increased significantly in VILI group and h IL-10 group(P<0.05), the activity of SOD decreased significantly in VILI group and h IL-10 group(P<0.05); compared with VILI group, the content of MDA and TP in BALF both decreased significantly in h IL-10 group(P<0.05), the activity of SOD increased significantly in h IL-10 group(P<0.05).5 The level of inflammatory cytokines in serum and BALF: when compared with Control group, all these were significantly increased in group VILI and group h IL-10, there were significant differences(P<0.05); compared with VILI group, all of them were significantly decreased in group h IL-10, the difference was statistically significant(P<0.05).6 Western blot: compared with Control group, the expression levels of p38 MAPK and NF-?B p65 both increased significantly in group VILI and group h IL-10, the differences were statistically significant(P<0.05), the level of ERK1 had no great difference(P>0.05); compared with group VILI, the expression levels of p38 MAPK ? ERK1 and NF- ? B p65 decreased significantly in group h IL-10, the difference was statistically significant(P<0.05).Conclusions:1 High tidal volume ventilation can induce acute lung injury, its mechanism may be due to the direct destruction of alveolar structure, resulting in the release of inflammatory mediators, enhancement of oxidative stress and so on.2 Human interleukin-10, as an important endogenous anti-inflammatory factor, by modulating the inflammatory response, improving oxygen, alleviating oxidative stress in the lung tissue to reduce VILI in rats in a certain extent.