Effects of Lª²NAME on bloodª²brain barrier permeability after acute carbon monoxide poisoning in rats

    WANG Xin, TIE Xinª²Xin, ZHANG Jingª²Ping, WAN Jianª²Hua, LIU Yu

    1Department of Infectious Diseases, 2Department of Neurosurgery, 3Department of Emergency, First Affiliated Hospital,China Medical University, Shenyang 110001,China

    ¡¾Abstract¡¿ AIM: To determine whether NO mediates bloodª²brain barrier (BBB) injury after acute CO poisoning in rats by investigating the effects of an NO synthase (NOS) inhibitor, N¦Øª²nitroª²Lª²arginine methyl ester (Lª²NAME), on BBB in COª²poisoned rats, and to explore the possible mechanisms involved in this process. METHODS: The experimental rat models of CO poisoning were established. Forty healthy female Spragueª²Dawley rats were separated into four groups. Lª²NAME (30 mg/kg, introperitoneally) was injected 15 min before or 30 min after CO exposure. Changes in BBB permeability were determined by detection of Evans blue (EB) content in rat brains with spectrophotometer 24 h after CO exposure. RESULTS: Compared with that in control group[(6.1¡À1.9) ¦Ìg/g], a significant increase in EB content was found in the rat brains that were COª²poisoned but not treated with Lª²NAME[(27.6¡À1.2) ¦Ìg/g] (P<0.01). However, EB extravasation was significantly restricted in groups that were treated with Lª²NAME 15 min before[(14.8¡À2.3) ¦Ìg/g ]or 30 min after CO exposure [(16.0¡À2.2) ¦Ìg/g ](P<0.01). CONCLUSION: The BBB permeability increases after acute CO poisoning, which can be significantly restricted by pretreatment with NOS inhibitor, indicating that BBB injury caused by acute CO poisoning is partially mediated by NO. ......