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Objective To investigate the role of endogenous Hydrogen Sulfide (H2S) in airway inflammation and responsiveness in a rat model of chronic passive-smoking.Methods Male SD rats were randomly divided into a control group (breathing fresh air) and a passive smoking group [cigarette smoking (CS) passively] ,with 18 rats in each group.Six rats in each group were randomly intraporitoneally injected with normal saline, sodium hydrosulfide (NailS) or propargylglycine (PPG, an irreversible inhibitor of cystathionine-γ-lyase).The animals were divided into six subgroups,ie.Con group, Naris group, and PPG group, CS group, CS + Naris group, and CS + PPG group.After 4 months,lung histological change and airway tension were measured.The H2 S levels of plasma and lung tissue were analyzed by the sensitive sulphur electrode assay.The expression of cystathionine-γ-lyase (CSE) was measured by western blot.Results Compared with the Con group, CSE protein expression in lung tissues was increased in CS group(P < 0.05) ; the H2S levels of plasma were significantly higher in GS group,NariS group and CS + Naris group,and much lower in PPG group (P < 0.05, respectively).Compared with CS group, the H2 S levels of plasma were significantly higher in CS + Naris group, and much lower in CS + PPG group (P < 0.05, respectively).The H2S level of lung tissue in each group had no significant difference (P > 0.05).Compared with Con group, score of lung pathology was significant elevated, and the responsiveness of airway smooth muscles to Ach and KCI was significant augmented in CS group.Compared with CS group, the score of lung pathology was decreased, and the responsiveness of airway smooth muscles was decreased in CS + NariS group(P < 0.05), and vise versa in CS + PPG group (P < 0.01).Conclusion H2 S can alleviate airway inflammation and hyperresponsiveness induced by CS, and administration of H2S might be of clinical benefit in airway inflammation and airway responsiveness.

9.Effects of continuous intermedin infusion on blood pressure and hemodynamic function in spontaneously hypertensive rats

Ying YUAN ; Xi WANG ; Qiang ZENG ; Hongmei WU ; Yongfen QI ; Chaoshu TANG

Journal of Geriatric Cardiology 2012;09(1):17-27

Objective To examine the effects of exogenously administered intermedin (IMD,adrenomedullin-2) on arterial blood pressure,cardiac function and the cardiovascular IMD receptor system in spontaneously hypertensive rats (SHRs) as well as to investigate the associated mechanisms.Methods Thirteen week-old male rats were divided in Wistar Kyoto (WKY) group (n =12),SHR group (n =12),IMD group (SHRs infused with IMD 1-47 500 ng/kg per hour,n =12),and ADM group (SHRs infused with adrenomedullin 500 ng/kg per hour,n =12).Results A two-week continuous administration of low dose IMD 1-47 via mini-osmotic pumps markedly reduced blood pressure,the maximal rates of increase and decrease of left-ventricle pressure development (LV ± dp/dtmax),left ventricular systolic pressure and heart rate in SHRs.Furthermore,IMD also inhibited protein over-expression of cardiovascular IMD receptors,myocardial Receptor Activity-Modifying Proteins (RAMP1 and RAMP2),aortic RAMP1,RAMP2,RAMP3,and calcitonin receptor-like receptor (CRLR);suppressed up-regulation of aortic RAMP1,RAMP2,RAMP3 and CRLR gene expression; and markedly elevated the mRNA abundance of myocardial atrial natriuretic peptide (ANP) and myocardial brain natriuretic peptide (BNP).Additionally,IMD 1-47 administration in SHRs increased aortic cAMP concentration and reduced myocardial cAMP concentration.Conclusion These findings support the speculation that IMD,as a cardiovascular active peptide,is involved in blood pressure reduction and cardiac function amelioration during hypertension.The mechanism underlying this effect may involve IMD binding of a receptor complex formed by RAMPs and CRLR,and consequential regulation of cAMP levels and other cardiovascular active factors,such as ANP and BNP.