Thosar Saurabh S, Bielko Sylvanna L, Wiggins Chad C, Klaunig James E, Mather Kieren J, Wallace Janet P
Department of Kinesiology, Indiana University School of Public Health, Indiana University, Bloomington, IN, USA.
Department of Environmental Health, Indiana University School of Public Health, Indiana University, Bloomington, IN, USA.
Med Sci Monit. 2015 Apr 7;21:1015-21. doi: 10.12659/MSM.893192.
This study was designed to test the hypothesis that antioxidant Vitamin C prevents the impairment of endothelial function during prolonged sitting.
Eleven men (24.2 ± 4.4 yrs) participated in 2 randomized 3-h sitting trials. In the sitting without vitamin C (SIT) and the sitting with vitamin C (VIT) trial, participants were seated for 3 h without moving their legs. Additionally, in the VIT trial, participants ingested 2 vitamin C tablets (1 g and 500 mg) at 30 min and 1 h 30 min, respectively. Superficial femoral artery (SFA) flow-mediated dilation (FMD) was measured hourly for 3 h.
By a 1-way ANOVA, there was a significant decline in FMD during 3 h of SIT (p<0.001). Simultaneously, there was a significant decline in antegrade (p=0.04) and mean (0.037) shear rates. For the SIT and VIT trials by a 2-way (trial x time) repeated measures ANOVA, there was a significant interaction (p=0.001). Pairwise testing revealed significant between-SFA FMD in the SIT and VIT trial at each hour after baseline, showing that VIT prevented the decline in FMD 1 h (p=0.009), 2 h (p=0.016), and 3 h (p=0.004). There was no difference in the shear rates between SIT and VIT trials (p>0.05).
Three hours of sitting resulted in impaired SFA FMD. Antioxidant Vitamin C prevented the decline in SFA FMD, suggesting that oxidative stress may contribute to the impairment in endothelial function during sitting.
本研究旨在验证抗氧化剂维生素C可预防长时间坐姿期间内皮功能受损这一假设。
11名男性（24.2±4.4岁）参与了2次随机的3小时坐姿试验。在无维生素C坐姿（SIT）试验和有维生素C坐姿（VIT）试验中，参与者双腿不动地坐3小时。此外，在VIT试验中，参与者分别在30分钟和1小时30分钟时服用2片维生素C片（1克和500毫克）。每小时测量股浅动脉（SFA）血流介导的舒张功能（FMD），持续3小时。
通过单因素方差分析，SIT试验的3小时内FMD显著下降（p<0.001）。同时，顺行切变率（p=0.04）和平均切变率（0.037）显著下降。对于SIT和VIT试验，通过双因素（试验x时间）重复测量方差分析，存在显著交互作用（p=0.001）。两两检验显示，基线后各小时SIT和VIT试验的SFA FMD之间存在显著差异，表明VIT可预防FMD在1小时（p=0.009）、2小时（p=0.016）和3小时（p=0.004）时下降。SIT和VIT试验的切变率无差异（p>0.05）。
3小时的坐姿导致SFA FMD受损。抗氧化剂维生素C可预防SFA FMD下降，表明氧化应激可能导致坐姿期间内皮功能受损。
