Protective effects of Ghrelin on ventilator-induced lung injury in rats

Abstract

Objective To investigate the effect of ghrelin pre-treatment on ventilator-induced lung injury. Methods Thirty-six male Sprague-Dawley (SD) rats weighing 280-320 g were randomly divided into three groups (n=12 each): control group, ventilator-induced lung injury group (VILI) and Ghrelin pre-treatment group.The control group was ventilated with Tidal volume (Vt) of 10 ml/kg and positive end expiratory pressure (PEEP) of 0 cmH2O at a rate of 40 breaths/min.The VILI group and Ghrelin pre-treatment group were ventilated with Vt of 30 ml/kg and PEEP of 0 cmH2O at a rate of 40 breaths/min.Rats in the Ghrelin treatment group were subcutaneously injected with Ghrelin (50 ng/kg) 30 min before ventilation.Equal amount of normal saline was given to rats other two groups at the same time.All animals were killed under over-dose anesthesia at 4 h after ventilation and the lungs tissue were harvested or examination of histopathology, wet/dry ratio, lung lavage liquid were collected to measure total protein, cytokines tumor necrosis factor-alpha (TNF-α) and IL-6, meanwhile, blood were drawed to test blood gas to calculate oxygenation index (PaO2/FiO2). Results Compared with the control group, lung tissue was seriously damaged, and total protein and cytokines in bronchoal veolar lavage fluid (BALF), W/D of lung tissue were significantly higher in VILI group.Compared with VILI group, the lung injury was less damaged, the total protein and cytokines in BALF was obviously reduced, the activity of MPO and the W/D were significantly reduced in the ghrelin pretreatment group. Conclusions Ghrelin pretreatment improves the degree of VILI by means of anti-inflammatory effects. Key words: Ghrelin; Lung injury, ventilator-induced; Cytokines