游泳对慢性低氧大鼠肺动脉L-精氨酸/一氧化氮途径的影响

目的 :探讨游泳锻炼对慢性低氧性肺动脉高压大鼠肺动脉L -精氨酸 /一氧化氮途径的影响。方法 :采用慢性低氧高二氧化碳肺动脉高压的大鼠进行游泳锻炼。将大鼠肺动脉孵育 ,测定其对[3 H]-L -Arg的摄取率、一氧化氮合酶 (NOS)活性与一氧化氮 (NO)含量。结果 :与模型对照组比 :游泳锻炼组的肺动脉平均压 (mPAP)降低 2 9 2 % (P <0 0 1 ) ,血浆NO代谢产物的含量升高 1 72 4% (P <0 0 1 ) ,肺动脉组织cNOS的活性升高 5 4 5 % (P <0 0 1 ) ,离体孵育肺动脉摄取低浓度 (0 2mmol/L)和高浓度 (5 0mmol/L) [3 H]-L -Arg分别升高 3 8 6% (P <0 0 1 )与 40 0 %(P <0 0 1 )。结论 :游泳锻炼有降低慢性低氧高二氧化碳大鼠肺动脉压 ,增加NO释放的作用 ,其机制可能是提高了L-Arg的跨膜转运与cNOS的活性

Effect of Swimming Exercise on L-Arginine/Nitric Oxide Pathway in Pulmonary Artery of Rats Chronically Exposed to Hypoxia and Hypercapnia

Objective To investigate the effects of swimming exercise on L-Arginine/nitric oxide(L-Arg/NO) pathway in pulmonary artery of rats chronically exposed to hypoxia and hypercapnia. Methods Thirty-one Sprague-Dawley rats were randomly divided into two groups, normal control group(NC) and chronic hypoxia-hypercapnia group. After four weeks exposed to hypoxia-hypercapnia, the latter group was subdivided into two: hypoxia-hypercapnia control group (HC) and swimming exercise group (SE). The rats of SE swam 30min/day, 6 days/week for 3weeks. Changes of L-Arg transport, NOS synthase activity in pulmonary artery, plasma nitrite content and L-Arg level were measured. Results In SE group, mean pulmonary artery pressure (mPAP) was decreased by 29 2% (P < 0 01), plasma nitrite level and cNOS activity of pulmonary artery were increased by 172 4% and 54 5%, respectively (P < 0 01), compared with HC group. At low (0 2mmol/L) or high (5 0mmol/L) concentration of L-Arg, the velocity of L-Arg transport in SE group was higher than that in HC group, respectively 38 6% and 40 0% (P < 0 01). Conclusion Swimming exercise decreases mPAP and increases NO production of rats chronically exposed to hypoxia and hypercapnia. The enhancement of L-Arg transport and cNOS activity in vessel would partly explain the mechanism.