Epigallocatechin-3-Gallate Ameliorates Glucocorticoid-Induced Osteoporosis of Rats in Vivo and in Vitro

Abstract

Background: Prolonged administration of overdoses of glucocorticoids results in increased bone remodeling, leading to glucocorticoid-induced osteoporosis (GIO), which is primarily due to the dysfunction and apoptosis of osteoblasts. The present study investigated the therapeutic effect and molecular mechanism of action of epigallocatechin-3-gallate (EGCG), a bioactive catechin in green tea, in high-dose dexamethasone-induced osteoblast differentiation in vivo and in vitro.Methods: The anti-dexamethasone (DEX) effects of EGCG on primary osteoblasts were determined on the basis of cell viability and alkaline phosphatase (ALP) and total cellular superoxide dismutase (SOD) activities. Flow cytometry and Western blot analysis were also used to evaluate the expression of related biomarkers in vitro, and bone microarchitecture was also extensively examined in a rat model in vivo.Results: The results showed that EGCG pretreatment significantly increased osteoblast viability and ALP and SOD activities when cells were exposed to DEX. Alizarin red staining indicated that there was more mineralization with EGCG pretreatment, countering DEX effects. EGCG reduced DEX-induced reactive oxygen species at both the mitochondrial and cellular levels in osteoblasts by activating the nuclear factor erythroid-derived 2-like-2 (Nrf2) pathway. In addition, EGCG protected osteoblasts from apoptosis. EGCG also regulated the formation of active glucocorticoid by 11β-hydroxysteroid dehydrogenase activity. Furthermore, femoral micro-computed tomography scans revealed that EGCG improved bone microstructure and mitigated DEX-induced deterioration of bone quality.Conclusion: These findings suggested that EGCG reversed GIO in rats by protecting osteoblasts by activating the Nrf2 signaling pathway.

Protective Effects of 2′,3′-Dihydroxy-4′,6′-dimethoxychalcone Derived from Green Perilla Leaves against UV Radiation-Induced Cell Injury in Human Cultured Keratinocytes

“…24) Skin effects and Nrf2-ARE pathway activation have been studied for the treatment of various other diseases and disorders, including chronic obstructive pulmonary disease, endometritis, and osteoporosis, thus suggesting the efficacy of DDC in the treatment and management of these diseases. [25][26][27] In recent years, DDC research has advanced for the purpose of exploring new compounds that enhance antioxidant function in vivo. Compounds that exhibit protective effects through the activation of the Nrf2-ARE pathway have also been identified in naturally derived plants other than green perilla.…”

“…Compounds that exhibit protective effects through the activation of the Nrf2-ARE pathway have also been identified in naturally derived plants other than green perilla. [28][29][30][31] Some of these compounds are derived from food sources and are considered safe and nontoxic 24,26) ; DDC used in this study is also a food-derived compound and is highly safe and approachable. Therefore, although further study is required in the future, DDC is expected to be useful in the prevention or treatment of skin damage caused by UV-A irradiation.…”

Epigallocatechin-3-Gallate Attenuates Adriamycin-Induced Focal Segmental Glomerulosclerosis via Suppression of Oxidant Stress and Apoptosis by Targeting Hypoxia-Inducible Factor-1α/ Angiopoietin-Like 4 Pathway

“…Thus, inhibiting ROS production and cell apoptosis may delay the progress of FSGS. Interestingly, EGCG have anti-oxidative and anti-apoptotic effects [7,8], which indicates its potential therapeutically effect in FSGS. In our study, both the ROS production and cell apoptosis were up-regulated following Adriamycin stimulation.…”

“…Epigallocatechin-3-gallate (EGCG) is a bioactive constituent accounting for more than 50% of the total catechins in green tea, which have anti-oxidative and antiapoptotic effects [7,8]. As described above, both ROS production and cell apoptosis are involved in FSGS, which indicates the potential therapeutically effect of EGCG in FSGS.…”

Influence of Green Tea Extract with Different Concentrations of Epigallocatechin Gallate on Calvaria Bone Repair of Ovariectomized Rats

“…The effects of EGCG on bone tissue were also studied by Liu et al (2018), both in vivo and in vitro. These authors demonstrated in vitro that EGCG is capable of increasing osteoblast viability as well as ALP and superoxide dismutase activity in rats with osteoporosis by glucocorticoid…”