Mitigation of Oxidative Damage by Green Tea Polyphenols and Tai Chi Exercise in Postmenopausal Women with Osteopenia

BackgroundOsteoporosis is a degenerative bone disease predominantly in postmenopausal women. Green tea polyphenols (GTP) and Tai Chi (TC) have been shown to be beneficial on human bone health. This study examined the efficacy of GTP and TC on mitigation of oxidative damage in postmenopausal women with osteopenia.
MethodsA 6-month randomized and placebo-controlled clinical trial was conducted in 171 postmenopausal women with osteopenia, who were recruited from Lubbock County, Texas. These participants were treated with placebo, GTP (500 mg daily), placebo + TC (60-minute group exercise, 3 times/week), or GTP (500 mg daily) + TC (60-minute group exercise, 3 times/week), respectively. Their blood and urine samples were collected at the baseline, 1-, 3- and 6-months during intervention for assessing levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidative DNA damage biomarker, and concentrations of serum and urine GTP components.
ResultsThe elevated concentrations of serum and urinary GTP components demonstrated a good adherence for the trial. A significant reduction of urinary 8-OHdG concentrations was found in all three treated groups during 3-month (P<0.001) and 6-month (P<0.001) intervention, as compared to the placebo group. The significant time- and dose-effects on mitigation of the oxidative damage biomarker were also found for GTP, TC, and GTP+TC intervened groups.
ConclusionOur study demonstrated that GTP and TC interventions were effective strategies of reducing the levels of oxidative stress, a putative mechanism for osteoporosis in postmenopausal women, and more importantly, working in an additive manner, which holds the potential as alternative tools to improve bone health in this population.
Trial RegistrationClinicalTrials.gov NCT00625391

### 研究背景
骨质疏松症是一种退行性骨病，高发于绝经后女性群体。绿茶多酚（Green Tea Polyphenols, GTP）与太极拳（Tai Chi, TC）已被证实对人体骨骼健康具有益处。本研究旨在探究绿茶多酚与太极拳对骨质减少症绝经后女性氧化损伤的改善效果。
### 研究方法
本研究针对从美国德克萨斯州拉伯克县招募的171名骨质减少症绝经后女性，开展了一项为期6个月的随机安慰剂对照临床试验。受试者被随机分为四组，分别接受安慰剂、每日500mg绿茶多酚、安慰剂联合太极拳（每周3次，每次60分钟团体锻炼）、每日500mg绿茶多酚联合太极拳（每周3次，每次60分钟团体锻炼）干预。分别于干预前（基线）、干预后1个月、3个月及6个月采集受试者血液与尿液样本，以检测氧化DNA损伤生物标志物8-羟基-2'-脱氧鸟苷（8-hydroxy-2′-deoxyguanosine, 8-OHdG）的水平，以及血清与尿液中绿茶多酚成分的浓度。
### 研究结果
血清与尿液中绿茶多酚成分浓度升高，表明本试验具有良好的受试者依从性。与安慰剂组相比，三个干预组在干预3个月（P<0.001）及6个月（P<0.001）时的尿液8-羟基-2'-脱氧鸟苷浓度均显著降低。此外，绿茶多酚、太极拳以及二者联合干预组均表现出对氧化损伤生物标志物改善的显著时间效应与剂量效应。
### 研究结论
本研究证实，绿茶多酚与太极拳干预可有效降低氧化应激水平——氧化应激被认为是绝经后女性骨质疏松症的潜在发病机制；更为重要的是，二者联合干预具有叠加增效作用，有望成为改善该群体骨骼健康的备选方案。
### 试验注册
ClinicalTrials.gov 编号NCT00625391