长期运动对十二指肠黏膜一氧化氮合成和铁贮存的调控效应

Effects of long-term exercise on regulating duodenal mucosal nitric oxide synthesis and iron storage

目的:观察长期运动对十二指肠黏膜一氧化氮合成和铁贮存的影响及一氧化氮对铁贮存的调节作用。方法:实验于2004-04/09在江苏大学医学院铁代谢研究室完成。①健康雌性SD大鼠40只,随机分为静息组、静息并应用一氧化氮抑制剂组、运动组、运动并应用一氧化氮抑制剂组,每组10只。②静息并应用一氧化氮抑制剂组和运动并应用一氧化氮抑制剂组饮用水中含有一氧化氮抑制剂(1g/L),运动组和运动并应用一氧化氮抑制剂组的大鼠游泳3个月。③3个月后分析各组大鼠血浆铁饱和度,一氧化氮浓度以及十二指肠黏膜一氧化氮含量和非血红素铁含量。结果:实验过程中死亡11只,进入结果分析29只(静息组8只、静息并应用一氧化氮抑制剂组5只、运动组8只、运动并应用一氧化氮抑制剂组8只)。①运动及一氧化氮抑制剂对大鼠血浆铁饱和度和一氧化氮浓度的影响:运动组的血浆铁饱和度低于静息组(P<0.01);运动并应用一氧化氮抑制剂组的血浆铁饱和度低于静息并应用一氧化氮抑制剂组(P<0.05),并且高于运动组(P<0.05)。运动组血浆一氧化氮浓度显著高于静息组(P<0.01);运动并应用一氧化氮抑制剂组的血浆一氧化氮浓度低于运动组(P<0.01),与静息并应用一氧化氮抑制剂组差别不显著(P>0.05)。②运动及一氧化氮抑制剂对大鼠十二指肠黏膜一氧化氮和非血红素铁含量的影响:运动组的十二指肠一氧化氮含量高于静息组(P<0.01);静息并应用一氧化氮抑制剂组的一氧化氮含量低于静息组(P<0.01);运动并应用一氧化氮抑制剂组的一氧化氮含量低于运动组(P<0.01),但高于静息并应用一氧化氮抑制剂组(P<0.01),与静息组差别不显著。与静息组比较,运动组和静息并应用一氧化氮抑制剂组的十二指肠黏膜非血红素铁含量均降低(P<0.05)。结论:静息状态下十二指肠黏膜细胞一氧化氮合成具有较高的紧张性,可能参与维持非血红素铁含量。长期运动可刺激十二指肠黏膜一氧化氮合成,降低铁贮存。但其机制是否涉及运动诱导的一氧化氮的直接作用以及是否参与铁吸收的调节有待于进一步研究。

AIM： To observe the effects of long-term exercise on duodenal mucosal nitric oxide （NO） synthesis and iron storage, and investigate the possible regulatory role of NO in iron storage. METHODS： The experiment was performed between April and September 2004 in the Department of Iron Metabolism, Medicine School of Jiangsu University. ①Forty Sprague-Dawley （SD） rats ware divided into sedentary group （SG1）, sedentary plus L-NAME group （SG2）, exercise group （EG1）, and exercise plus L-NAME group （EG2）, with 10 rats in each.②L-NAME （1 g/L） was administrated into the EG2 and SG2 by the drinking water. The rats in EG1 and EG2 swam for three months. ③At the end of the experimental period （3 months）, plasma transferrin saturation （TS） and NOx concentration, and duodenal mucosal NOx contents and non-heine iron （NHI） contents were analyzed, respectively. RESULTS： Except 11 deaths during the experiment, a total of 29 rats entered the result analysis, including 8 in SG1, 5 in SG2, 8 in EG1 and 8 in EG2.①The effects of exercise and L-NAME on plasma TS and NOx concentration in the rats： As compared to the SG1, the EG1 had the Iowar TS （P〈 0.001）. TS in the EG2 was Iowar than that in the SG2 （P〈 0.05）, but higher than that in the EG1 （P〈 0.05）. Plasma NOx concentration in the EG1 was significantly higher than that in SG1 （P〈 0.01） and it was lower in the EG2 than in the EG1 （P〈 0.01）, but there was no significant difference （P〉 0.05） from that in the SG2.②The effects of exercise and L-NAME on duodenal mucosal NOx and NHI contents in the rats： Compared to the SG1, duodenal mucosal NOx contents ware higher in the EG1 （P〈 0.001）, and significantly lower in the SG2 （P〈 0.001）. Duodenal mucosal NOx contents in the EG2 ware lower than that in the EG1 （P〈 0.001）, and significantly higher than that in the SG2 （P 〈 0.001）. No significant difference in duodenal mucosal NOx contents was found between the EG2 and the SG1. Compared with the SG1, duodenal mucosal NHI contents both in the EG1 and in the SG2 were decreased （P 〈 0.05）. CONCLUSION： Under the sedentary condition, duodenal mucosa may have a highly tonic NO synthesis, which could be involved in maintenance of NHI contents. Long-term exercise may stimulate synthesis of duodenal mucosal NO, and decrease duodenal mucosal iron storage. Long-term exercise regulates duodenal mucosal iron storage, but whether its mechanisms may involve the direct action of exercise-induced NO and whether it may take part in the regulation of iron absorption remains to be determined.