The Role Of Inducible Nitric Oxide Synthase, Nitric Oxide In The Ventilaor Induced Lung Injury And Its Prevention And Treatment In Rats

Objective:To explore the role of nitric oxide(NO)in acute lung injury induced by different tidal volume of ventilation in rats and its prevention and treatment of glucocorticoid,aminoguanidine in the ventilaor induced lung injury by detecting the expression of inducible nitric oxide synthase(iNOS)in lung tissue.Methods:1 Twenty-four male Wistar rats were randomly divided into three groups:control group, low tidal volume(L-V_T)group, high tidal volume(H-V_T)group.The pathologic alterations of the lungs were observed under light microscope in groups, and the expression of iNOS in lung tissue was measured by immunohistochemistry and RT-PCR,and the content of NO in plasma and lung tissue were measured,and the level of T-AOC in plasma and lung tissue were measured.2 Thirty-two male Wistar rats were randomly divided into four groups:control group, high tidal volume group; Dexamethasone(DEX)group and aminoguanidine(AG)group.The same indexes were measured.Results:1⑴Different levels of interstitial and alveolar edema,infiltration and activation of inflammation cells could be seen in the H-V_T group. There was no obvious pathologic difference between the control group and the L-V_T group(P>0.05).⑵The expression of iNOS mRNA and protein in lung tissue were significantly higher in rats in the H-V_T group than those in the control group and L-V_T group(P<0.01).There was no statistical difference between the last two groups(P>0.05).⑶The content of NO in plasma and lung tissue were significantly higher in rats in the H-V_T group than those in the control group and L-V_T group(P<0.01).There was no statistical difference between the last two groups(P>0.05).⑷The level of T-AOC in plasma and lung tissue were significantly lower in rats in the H-V_T group than those in the control group and L-V_T group(P<0.01).There was no statistical difference between the last two groups(P>0.05).2⑴Apart from the control group,different levels of interstitial and alveolar edema,infiltration and activation of inflammation cells could be seen in experimental groups. There was more obvious pathologic alterations in the H-V_T group. ⑵The expression of iNOS mRNA and protein in lung tissue were significantly higher in rats in the H-V_T group than those in the DEX group and AG group(P<0.01).There was no statistical difference between the last two groups(P>0.05).⑶The content of NO in plasma and lung tissue were significantly higher in rats in the H-V_T group than those in the DEX group and AG group(P<0.01).There was no statistical difference between the last two groups(P>0.05).⑷The level of T-AOC in plasma and lung tissue were significantly lower in rats in the H-V_T group than those in the DEX group and AG group(P<0.01,P<0.05).But the AG group was lower than the DEX group(P<0.01).Conclusion:1.NO play a certain role in the ventilator induced lung injury by the activating of iNOS in vivo.2.There was a small effect on the content of NO in the L-V_T group and no obvious lung injury.3.Dexamethasone and Aminoguanidine may play a role of prevention and treatment in the ventilator induced lung injury by inhibiting the expression of iNOS and reducing the production of NO subsequently.