Restructure Of Pulmonary Vessel In Hypoxic Pulmonary Hypertension (HPH) Rats And The Interference Effect Of Magnesium Agent

Restructure of Pulmonary Vessel in hypoxic pulmonary hypertension (HPH) Rats and the Interference Effect of Magnesium AgentAbstractObjective: To investigate the effect of hypoxic pulmonary hypertension (HPH) in pulmonary vascular remodeling of rat; change of Endothelin-1 (ET-1), Thromboxane A2 (TXA2), Prostacyclin (PGI2),Superoxide dismutase (SOD), Malondialdehyde(MDA) in lung tissue, and observe the prevention and therapeutics effect of Potassium Magnesium-L-Aspartate(PM-L-A) on hypoxic structural remodeling of intraacinar pulmonary arteries(IAPA).Methods: 21 190~230g weight rats were divided into Control (C) ,HPH (H) and Treatment (T) groups, each had 7 rats. The rats of H group and T group were fed in hypoxic environment under normal atmospheric pressure (10.0±0.5%O2, 8 hours /day). T group was administrated with PM-L-A and others administrated normal saline correspondingly. On the 30th day of hypoxia, mean pulmonary artery press (mPAP), mean carotid arterial press (mCAP), right ventricle hypertrophy index (RVHI) examined; MDA, SOD were detected by using thiobarbituric acid method; ET-1, TXA2, PGI2, in lung tissue were measured by means of the radio-immunoassay. Muscularizing degree of intraacinar pulmonary artery (IAPA), relative medial thickness (RMT) and relative medial acreage (RMA) of small pulmonary muscularized arteries was measured and pulmonary vessel changes were studied under light and electron microscope with morphometric analysis.Results: (1) mPAP and RVHI in H group were significantly higher than that in C group (P<0.01), mPAP and RVHI in T group were evidently lower than that in H group (P<0.01), There was no significant difference in mCAP among three groups. (2) In IAPA, the rate of muscular artery (MA), partially muscular artery (PMA) in H group were much higher than that in C group (P<0.01), the rate of non-muscular artery (NMA) in H group were much lower than that in C group (P<0.01), RMT and RMA of IAPA in H group were evidently bigger than that in C group (P<0.01), which were studied under light microscope. In IAPA, the rate of MA, PMA in T group were much lower than that in H group(P<0.01). The rate of NMA in T group were much higher than that in H group (P<0.01), The RMT and RMA of IAPA in T group were also evidently lower than that in H group (P<0.01).(3)The contents of ET-1,TXA2,MDA in the lung tissue of H group were significantly increased than C group(P<0.05), in the contrast the contents of PGI2,SOD was decreased as compared with that in C group(P<0.05), The contents of ET-1,TXA2,MDA in the lung tissue of T group were evidently decreased than that in H group(P<0.05), The content of PGI2,SOD were much higher than that in H group(P<0.05). (4) Endotheliocyte of small pulmonary muscularized arteries in H group proliferated, plumped, swelled and smooth muscle cells plumped and there were lots of mitochondrias and endoplasmic reticulums in the cytoplasm.Conclusion: (1) Rate of NMA in HPH rats was decreased markedly, rate of MA was increased evidently, RMT,RMA in small pulmonary muscularized arteries in HPH rats were increased markedly, non-muscular artery muscularizing was observed, which results in the restructure ofpulmonary vessel. (2) The content of ET-1,TXA2 and oxide free radical in lung tissue of HPH rats were markedly increased, when contents of PGI2,SOD decreased obviously in H group, which related with the pathogenesis of HPH and HPVR. (3) PM-L-A reduced the production of ET-1,TXA2 and oxide free radical and the restructure of pulmonary vessel, increased contents of PGI2,SOD.(4) PM-L-A may play important roles in inhibiting remodeling of IAPA and reducing hypoxic pulmonary hypertension(HPH).