Role of gamma-aminobutyric acid A receptor in lung tissues in lipopolysaccharide-induced acute lung injury in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the role of gamma-aminobutyric acid (GABA) A receptor (GABAAR) in lung tissues in lipopolysaccharide (LPS)-induced acute lung injury in rats.Methods Thirty-two male Wistar rats,aged 8 weeks,weighing 200-230 g,were randomly divided into 4 groups (n =8 each) ∶ control group (group C),group LPS,GABA pretreatment + LPS group (group GABA) and GABAAR antagonist bicuculline pretreatment + LPS group (group BIC).Acute lung injury was induced by intravenous LPS 5 mg/kg in groups LPS,GABA and BIC,while the equal volume of normal saline was given in group C.GABA 50 mg/kg and bicuculline 10 μmol/kg were injected intraperitoneally 30 min before LPS injection in GABA and BIC groups,respectively.Arterial blood samples were collected at 6 h after LPS injection for measurement of arterial partial pressure of oxygen (PaO2).The animals were then sacrificed and lungs removed for determination of W/D lung weight ratio,GABAAR expression,contents of interleukin-6 (IL-6),tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA) and superoxide dismutase (SOD) activity in lung tissues and for microscopic examination.Results Compared with group C,PaO2 was significantly decreased in the other three groups,and W/D lung weight ratio,TNF-α,IL-6 and MDA contents were significantly increased,GABAAR expression was up-regulated,and SOD activity was decreased in groups LPS and GABA (P ＜ 0.05).Compared with group LPS,W/D lung weight ratio,TNF-α,IL-6 and MDA contents were significantly increased,GABAAR expression was up-regulated,and SOD activity was decreased in group GABA (P ＜ 0.05),and no significant change was found in the parameters mentioned above in group BIC and in PaO2 in groups GABA and BIC (P ＞ 0.05).Conclusion GABAA R in lung tissues is involved in the development of acute lung injury induced by LPS.