Experimental Studies On The Therapeutic Effect Of Fasudil On Ventilator-induced Lung Injury In Rat

Objective:To establish a ventilator-induced lung injury model in rats by mechanical ventilation with different tidal volume,and observing the rat arterial blood gas changes,changes lung tissues pathological,lung wet and dry ratio changes,the contents change of inflammatory cytokine include IL-1??IL-6?IL-8?TNF-a,in rats bronchoalveolar lavage fluid and the tatio Change of autophagy-related protein microtubule-associated protein 1 light chain 3 ? and microtubule-associated protein1 light chain 3?(LC3-?/LC3-?)in lung tissues after mechanical ventilation with different tidal volume changes.T0 observe the therapeutic effect of after addition fasudil in rats ventilator-induced lung injury then provide a new treatment method for the clinical treatment of VILI.Methods:Model Establishment and experimental groups Part one : Different tidal volume on the influence of the lung function in rats.Sprague-Dawley rats were randomly divided into four groups,A group(spontaneous breathing),group B(VT = 10ml/ Kg),C group(VT = 20 ml / kg),D group(VT = 40 ml / kg).then each group was randomly divided into three sub-groups again by 1h,2h and 4h separatedly.To observe the changes of arterial blood gas,changes of lung wet and dry ratio,the changes of IL-1B,IL-6,IL-8,TNF-a in rats BALF,To observe the pathological changes of lung tissue and the changes of LC3-?/LC3-?in lung tissues after mechanical ventilation 4 hours.According to the results to establish rat VILI model.Part two : Study of Fasudil intervention in rat VILI Sprague-Dawley rats were randomly divided into three groups,group S (spontaneous breathing),group V(VILI group),group F(group V+fasudil),group V was in accordance with VT = 40 ml / kg model.group F was based on the V Group injection with fasudil 15ml/kg via the tail vein.then each group was randomly divided into three sub-groups again by 1h,2h and 4h separatedly.To observe the changes of arterial blood gas,changes of lung wet and dry ratio,the changes of IL-1?,IL-6,IL-8,TNF-? in rats BALF,the pathological changes of lung tissue and the changes of LC3-?/LC3-?in lung tissues after mechanical ventilation 4 hours?Results:Compared to the control group(group A and group B),group C and group D arterial blood gas Pa O2?p H were gradually decreased with ventilation time.The difference were significant(P<0.05).the W/D were significantly increased,the difference significant(P<0.05).the content of IL-1?,IL-6,IL-8,TNF-? in group C and group D were significantly higher than group A and group B with time,the differences were significant(P<0.05),group D was significant higher than group C,the difference was significant(P<0.05).Observing the lung tissue HE staining under electron microscopy we can see there were clear alveolar structure,no lung tissue destruction in group A and group B,while in group C and group D showed serious structural damage to the alveolar,the alveolar surface scattered bleeding points,a lot of bleeding,some alveolar fusion.L group C were better than group D.the LC3-?/LC3-?in group C and group D were higher than group A and group B,the differences were significant(P<0.05),compared group C with group D,the difference was significant(P<0.05)after mechanical ventilation 4 hours.Compared to the control group S,group V and group F arterial blood gas Pa O2?p H were gradually decreased with time.The difference were significant(P<0.05),While in the same time point,the Pa O2 and p H in group F were higher than group V,the difference were significant(P<0.05).the W/D were significantly increased in group V and group F,the difference were significant(P<0.05).The content of IL-1?,IL-6,IL-8,TNF-a and LC-3 in group V and group F were significantly higher than group S with time,the differences were significant(P<0.05),while the content in group F were lower than group V,the differences were significant(P<0.05).Observing the lung tissue HE staining under electron microscopy we can see there were clear alveolar structure,no lung tissue destruction in group S,while in group V and group F showed serious structural damage to the alveolar,the alveolar surface scattered bleeding points,some alveolar fusion,lung tissue damages in group F were lighter than group V.the LC3-?/LC3-?group V and group F were higher than group S,the differences were significant(P<0.05),compared group V with group F,the difference was significant(P<0.05)after mechanical ventilation 4 hours.Conclusion:1?After different tidal volume mechanical ventilation in rats,VT=20 ml/kg and40ml/kg may induced lung injury,which VT=40ml/kg present more obvious,it was more suitable for the establishment of VILI model.2? In VILI model,after intervention with fasudil,the inflammatory cytokines in BALF and the pathological changes of lung tissues,the expression of autophgay in lung tissues were significantly decreased,That indicate fasudil have a therapeutic effect in rat VILI which may be related to inhibit the activation of Rho signaling pathway and the expression of autophagy in VILI.