Abstract:

Objective To investigate the effect of isoflurane (ISO) posttreatment on the membrane permeability of alveolar capillaries and activity of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in acute lung injury (ALI) induced by sepsis in rats. Methods One hundred and twenty male SD rats were randomly divided into sham operation group (Sham group), ISO intervention after sham operation group (Sham-ISO group), ALI model induced by sepsis group (ALI group) and ISO intervention after ALI induced by sepsis group (ALI-ISO group), with 30 rats in each group. Rats in ALI group and ALI-ISO group were selected, and ALI model induced by sepsis was established by cecal ligation and puncture (CLP). Six hours after model establishment, rats in ALI-ISO group inhaled 1.0 MAC ISO for 2 h. Ten rats in each group were served for survival analysis. Ten rats in each group were randomly selected, Evans blue was intravenously injected 30min before sacrifice, lung tissues were obtained for examination of permeability of alveoli (Evans blue content determination). Blood samples were taken from the rest of 10 rats in each group before sacrifice, serum NO contents were measured, right lung tissues were obtained for histopathological examination and protein detection, wet/dry weight ratios and water content were measured, neutrophil counts in bronchoalveolar lavage fluid (BALF) were obtained, lung permeability indexes (LPI) were calculated, and the activity of iNOS in lung tissues was determined. Results The survival of rats in ALI-ISO group 24 h,48 h and 10 d after model establishment was higher than that in ALI group. The parameters of histopathologic accumulative score, lung wet/dry weight ratio, water content of lung, Evans blue content in lung tissues, LPI, serum NO content and activity of iNOS in lung tissues in ALI group and ALI-ISO group were significantly higher than those in Sham group and Sham-ISO group (P<0.05), while these parameters in ALI-ISO group were significantly lower than those in ALI group (P<0.05). The neutrophil counts in BALF in ALI group and ALI-ISO group were significantly higher than those in Sham group and Sham-ISO group (P<0.05), while there was no significant difference between ALI group and ALI-ISO group (P>0.05). Conclusion Posttreatment with 1.0 MAC ISO can reduce the membrane permeability of alveolar capillaries in ALI induced by sepsis, attenuate severity of ALI, and increase the survival.

Key words: isoflurane, posttreatment, acute lung injury, membrane permeability of alveolar capillary, nitric oxide, inducible nitric oxide synthase