| Co-Investigator(Kenkyū-buntansha) |
AMESHIMA Shingo Fukui Medical University, Faculty of Medicine, Assistant, 医学部附属病院, 助手 (60262614)
MATSUKAWA Shigeru Fukui Medical University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (00092809)
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| Research Abstract |
Does acute lung (vascular) injury occur when nitric oxide and O_2-exgenously given? If so, dose apoptosis take a role? Does pulmonary vascular endothelial cell cause apoptosis by leukotoxin, an epoxide of linolate? To answer these questions we did some experiments by using isolated perfused rat lungs (IPRL). IPRL were ventilated either with 21% O_2,40% O_2 or 95% O_2 containing air while NO donor (NOC7) either at doses of 0muM,10muM,50muM was added to the perfusate reservoir. Some IPRL were treated either with 160muM peroxynitrite or 320muM ONOO-. Among experimental groups of 95%O_2+NOC7 100muM,95%O_2+NOC7 50muM,95%O_2+NO7 10muM,95%O_2 alone, 40%O_2+NOC7 100muM,40%O_2+NOC7 50muM,40%O_2+NOC7 10muM,40%O_2 alone, 21%O_2+NOC7 100muM,21%O_2+NOC7 50muM,and 21%O_2 alone, group of 40%O_2+NOC7 100muM showed significant increase in lung wet weight/dry weight, perfusate LDH activity. ONOO- caused no significant effects. Since change of pulmonary perfusion pressure was not observed, 40%O_2+NOC7 100muM seemed to exert permeability edema. Thus acute lung injury could be established when optimal molecular ratio of NO and O_2- was reached. When human pulmonary arterial endothelial cells (HPAEC) were incuvated with leukotoxin (Lx), HPAEC immediately produced O_2-. Allopurinol but not indomethacin, apocinin, SOD or LNMMA suppressed such an effect, suggesting that O_2- from HPAEC was produced by xanthine oxidase which was stimulated by Lx. Lx at lower dose elicited apoptosis of HAVEC (detected by tunel method and DNA fragmentation) and caused cell necrosis at higher dose, respectively.
In summary, Lx has a potential of apoptosis of vascular endothelium via production of oxygen radical and NO metabolites.
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