Supplementary Material for: White Tea Reduced Bone Loss by Suppressing the TRAP/CTX Pathway in Ovariectomy-Induced Osteoporosis Model Rats

Osteoporosis is an important skeletal disease characterized by bone weakness and high risk of fracture in postmenopausal women. Tea consumption is known to play an important role in the prevention or alleviation of osteoporosis. However, the therapeutic effects of aqueous extracts of white tea (WT) have not been evaluated in osteoporosis rat models. The aim of this study was to investigate the potential anti-osteoporotic role of WT in ovariectomized (OVX) rats. WT was given orally at 0.5% w/v doses for 12 weeks in OVX rats. Biochemical parameters in blood samples, bone tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide of type 1 collagen (CTX) and estradiol levels were evaluated. Bone mineral density and bone mineral content values were measured in the left femur. In addition to histopathological examination, osteolcalcin, osteopontin and TUNEL levels were determined. OVX group data demonstrated that bone loss occurred by thinning of the metaphyseal growth plates of the femur. Similarly, the levels of TRAP and CTX, markers of osteoclastic activity, were found to be high concurrently with a decrease in femoral bone mineral density. In addition, increased osteolcalcin and osteopontin levels were present in the metaphyseal growth zones. On the other hand, while TRAP and CTX levels were suppressed in the OVX-WT group, bone mineral content increased. In ad­dition, TUNEL, osteocalcin and osteopontin positivity decreased in the right femoral metaphysis growth zones, proliferating zone and resting zone cells. These results showed that chronic WT consumption has a protective effect by reducing bone resorption in OVX-induced osteoporotic rats.

骨质疏松症（Osteoporosis）是一类重要的骨骼疾病，以骨强度减弱、绝经后女性骨折风险升高为核心特征。现有研究证实，饮茶在骨质疏松症的预防与缓解中具有重要作用。然而，白茶（white tea, WT）水提取物的治疗效应尚未在骨质疏松大鼠模型中得到评估。本研究旨在探讨白茶对去卵巢（ovariectomized, OVX）大鼠的潜在抗骨质疏松作用。研究者以0.5%质量体积比的白茶水提取物对去卵巢大鼠进行为期12周的灌胃给药。检测血液样本中的生化指标、骨组织抗酒石酸酸性磷酸酶（tartrate-resistant acid phosphatase, TRAP）、Ⅰ型胶原C端肽（C-terminal telopeptide of type 1 collagen, CTX）及雌二醇水平；测定左侧股骨的骨密度与骨矿含量。除开展组织病理学检查外，同时检测骨钙素（osteocalcin）、骨桥蛋白（osteopontin）及原位末端转移酶标记技术（TUNEL）的表达水平。去卵巢组大鼠的实验数据显示，股骨骨骺生长板变薄可引发骨量丢失。同样，作为破骨细胞活性标志物的TRAP与CTX水平显著升高，同时股骨骨密度降低；骨骺生长区的骨钙素与骨桥蛋白水平亦出现上调。另一方面，去卵巢+白茶给药组（OVX-WT组）的TRAP与CTX水平受到显著抑制，骨矿含量则有所升高。此外，右侧股骨骨骺生长区、增殖区及静止区细胞的TUNEL、骨钙素及骨桥蛋白阳性表达均明显降低。上述结果表明，长期白茶摄入可通过抑制去卵巢诱导的骨质疏松大鼠的骨吸收过程，发挥骨骼保护效应。