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）是一类以骨强度降低、绝经后女性骨折风险显著升高为特征的重要骨骼疾病。已有研究证实饮茶在骨质疏松症的预防与病情缓解中具有重要作用。然而，白茶（WT）水提取物的治疗效应尚未在骨质疏松大鼠模型中开展相关评估。本研究旨在探究白茶在去卵巢（OVX）大鼠中潜在的抗骨质疏松功效。本研究以0.5%重量体积比（w/v）的白茶制剂对去卵巢大鼠进行灌胃给药，持续干预12周。随后检测血液样本中的生化指标、骨抗酒石酸酸性磷酸酶（TRAP）、Ⅰ型胶原C端肽（CTX）及雌二醇水平；同时测定左侧股骨的骨密度与骨矿含量。此外，通过组织病理学检查，对骨钙素、骨桥蛋白及原位末端转移酶标记技术（TUNEL）的表达水平进行检测。去卵巢组大鼠的实验数据显示，股骨干骺端生长板变薄可诱发骨丢失。与之相符的是，作为破骨细胞活性标志物的TRAP与CTX水平显著升高，同时股骨骨密度出现下降；且干骺端生长区的骨钙素、骨桥蛋白表达水平上调。而在白茶干预组（OVX-WT组）中，TRAP与CTX的表达受到抑制，骨矿含量则有所提升。此外，右侧股骨干骺端生长区、增殖区及静止区细胞的TUNEL、骨钙素与骨桥蛋白阳性表达均显著下调。上述研究结果表明，长期饮用白茶可通过抑制去卵巢诱导的骨质疏松大鼠的骨吸收过程，发挥骨保护作用。