Protective effects of N-acetylcystine on pulmonary microvascular permeability of lung injury in dog after cardiopulmonary bypass / 中华急诊医学杂志

ABSTRACT

Objective To evaluate the protective effect on the pulmonary micmvascolar permeability and thereby to ameliorate the lungs injury attributed to cardiopuimonary bypass(CPB).Method Twenty-four adult hybrid health dogs were randomly divided into three groups(8 in each group)group C(normal saline given after CPB),group N1(NAC given intravenously just before CPB)and group N2(NAC given just after CPB).The changes of respiratory index(RI)and malondialdehyde(MDA)content in lung tissue were observed.Samples were taken three times,before CPB(T0),30 min after CPB surned off(T1)and 60 min after CPB sumed off(T2).The leucocyte count and slbumin content in bronchoalveolar lavage fluid(BAlF),the pulmonary micmvascular permeability index(PMPI),and the histological changes of lung under light microscope and electromicroscope in 3 groups were examined.Results No significant differences were found in the levels of Ri and MDA content of lung tissue between groups before CPB.However,they gradually reduced after CPB(P<0.05)in the three groups,but they still were significantly lower in group N1 and group N2 compared with those in group C at,T1 and T2(P<0.05)and those in group N1 were significantly lowere than those in group N2 at T1 and T2(P<0.05).MDA gradually increased after CPB in three groups(P<0.05),but it was still significantly lower in group N1 and group N2 than that in group C at T1 and T2(P<0.05).The leucocyte count and albumin content in BALF were significantly lower in group N1 and group N2 in comparison with those in group C(P<0.05)and they were significantly lower in group N1 compared with those in group N2(P<0.05).The PMPI were significantly lower in group N1 and sroup N2 compared with those in group C(P<0.05)and they were significantly lower in group N1 compared with those in group N2(P<0.05).By using electromicroscope,the apparent inflammatory change of lung with endothelium cellular swelling,inter-endothelial cells spaces widened,and the indistinctness,deformation or decurtation of microfilarnent were observed.And the dissolution of laminated body,swollen mitochondria and plasmolysis were found in alveolar epithelial cell Ⅱ in group C.However,these changes were markedly alleviated in group N2 and group N1.Conclusions The results clearly demonstrate that NAC could protectie effect on the CPB injured lung and reduce the pulmonary microvascalar permeability,and the protetive effect is better in group N1 than that in group N2.