AIMTo investigate the effects of L-arginine liposome on nitric oxide(NO) and nitric oxide synthase gene (NOS mRNA) in rats chronically exposed to hypoxia-hypercapnia.

METHODSFourty male SD rats were randomly divided into four groups (n=10): normal control group(NC), hypoxia-hypercapnia group (HH), hypoxia-hypercapnia + L-arginine group(HL) and hypoxia-hypercapnia + L-arginine liposome group (HP). Contents of NO in plasma were measured using colorimetric analysis. Expression of nitric oxide synthase gene were measured with situ hybridization.

RESULTS(1) The mean pulmonary artery pressure(mPAP) and weight ratio of right ventricle to left ventricle and septum(RV/LV + S) of HP group were obviously lower than those of HH group and HL group. (2) The NO contents in plasma of HP group were obviously higher than those of HH group and HL group (P < 0.01). (3) Situ hybridization showed the average value of integral light density(LD) of ecNOS mRNA in pulmonary arterioles was significantly higher in rats of HP group than that of HH group and HL group (P < 0.01). (4) Light microscopy showed WA/TA (vessel wall area/total area) and PAMT (media thickness ratio of pulmonary arterioles) were significantly lower in rats of HP group than those of HH group (P < 0.01).

CONCLUSIONL-arginine liposome could lower the mPAP and lighten the remodeling of pulmonary arterioles of the rats chronically exposed to hypoxia-hypercapnia than L-arginine does. It suggests that L-arginine liposome significantly promotes the membrane transportin of L-arginine.