Green tea (Camellia sinensis) aqueous extract alleviates postmenopausal osteoporosis in ovariectomized rats and prevents RANKL-induced osteoclastogenesis in vitro.

Xin Wu,Xuan-Jun Wang,Qiang-Qiang Zhu,Chuan-Qi Xie,Jun Sheng,Chang Shen,Ming-Yue Wang,Bin Sun,Yan-Ping Huang,Meng-Fei An,Yun-Li Zhao

doi:10.29219/fnr.v62.1478

Abstract

BackgroundGreen tea (Camelliasinensis [L.] Kuntze) belongs to the plant family Theaceae and is mainly distributed in East Asia, the Indian subcontinent and Southeast Asia. This plant has been proven to be beneficial to human health, and green tea is the second most consumed beverage in the world after water. However, until now, the effect of green tea aqueous extract (GTE) upon postmenopausal osteoporosis has remained unclear. In this study, we investigated the therapeutic effects of GTE on estrogen deficiency-induced osteoporosis and explored the possible mechanisms in vivo and in vitro.Materials and methodsOvariectomized (OVX) female rats were orally administered with GTE at doses of 60, 120, and 370 mg kg−1 for 13 consecutive weeks. The biochemical parameters, bone gla protein, alkaline phosphatase, acid phosphatase, estrogen, interleukin-1β, and interleukin-6 in blood samples were detected, and histological change in bones was analyzed by hematoxylin and eosin staining. Meanwhile, the mechanisms of GTE on osteoclast formation were explored in RAW 264.7 cells induced by receptor activation of the nuclear factor kappa B ligand (RANKL).ResultsThe results showed that GTE could increase bone mass and inhibit trabecular bone loss in OVX rats. Furthermore, real-time quantitative reverse transcription polymerase chain reaction analysis from in vitro experiments also showed that GTE reduced the mRNA expression of osteoclast-associated genes such as cathepsin K (cath-K), c-Fos, matrix metalloproteinase 9, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and tartrate-resistant acid phosphatase. In addition, GTE caused a reduction in the protein levels of NFATc1, c-Fos, c-src and cath-K.ConclusionEvidence from both animal models and in vitro experiments suggested that GTE might effectively ameliorate the symptoms of osteoporosis in OVX rats and inhibit RANKL-induced osteoclast-specific gene and protein expression.

Highlights

Green tea (Camelliasinensis [L.] Kuntze) belongs to the plant family Theaceae and is mainly distributed in East Asia, the Indian subcontinent and Southeast Asia
Body weight did not increase in the XLGB group compared with the model group and there were no significant differences between the green tea aqueous extract (GTE) groups and the model group during the first 7 weeks of treatment
GTE influenced the serology indicators of Postmenopausal osteoporosis (PMOP) in OVX rats In order to examine the effect of GTE upon serology indicators of PMOP in OVX rats, serum Bone gla protein (BGP), Alkaline phosphatase (ALP), acid phosphatase (ACP), E2, and plasma IL-1β and IL-6 levels were determined using appropriate assay kits (Fig. 1)

Summary

Introduction

Green tea (Camelliasinensis [L.] Kuntze) belongs to the plant family Theaceae and is mainly distributed in East Asia, the Indian subcontinent and Southeast Asia. The mechanisms of GTE on osteoclast formation were explored in RAW 264.7 cells induced by receptor activation of the nuclear factor kappa B ligand (RANKL). Real-time quantitative reverse transcription polymerase chain reaction analysis from in vitro experiments showed that GTE reduced the mRNA expression of osteoclast-associated genes such as cathepsin K (cath-K), c-Fos, matrix metalloproteinase 9, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and tartrate-resistant acid phosphatase. Conclusion: Evidence from both animal models and in vitro experiments suggested that GTE might effectively ameliorate the symptoms of osteoporosis in OVX rats and inhibit RANKL-induced osteoclast-specific gene and protein expression

Methods

Results

Conclusion