Effect of green tea extract (GTE) in the metabolism and gene expression of osteoblastic cells from calvaria of ovariectomized rats

Abstract

Osteoporosis is a common disease in the postmenopausal period and it is characterized by fragility and loss of bone mass, which might result in severe fractures. Several factors like chronic inflammation and estrogen deficiency are capable of promoting loss of bone mass, because of oxidative stress increase or reduced antioxidative capacity. Thus, antioxidants beverages like green tea have been receiving increasing attention. Green tea extract (GTE) is rich in antioxidants denominated catechins, which are suggested to have anti-inflammatory and antioxidant properties, reducing bone resorption and increasing bone formation. Thus, the aim of this investigation is to perform in vitro assays to evaluate the metabolism of osteoblastic cells from calvaria of ovariectomized rats in the presence of green tea extract (GTE). There will be used wistar female rats, which will be submitted to ovariectomy and after 60 days sacrificed for removal of calvaria fragments. Cells will be isolated and cultivated in cell flasks with osteogenic medium. After subconfluence, cells will be seeded in cell plates of 24 wells in a concentration of 2 x 104 cells/well (n=5) and divided into four groups: control without GTE (C); control with GTE (CGTE); ovariectomized without GTE (O) and ovariectomized with GTE (OGTE). After the experimental periods, the following parameters will be evaluated: cell proliferation and viability, alkaline phosphatase activity, detection and quantification of mineralized nodules, as well as quantitative expression of genes associated to bone metabolism (i.e. ALP, OCN, RANK, RANKL and OPG). Data obtained will be analyzed by statistical softwares for significance of pd0.05, with the goal of finding relevant results of the beneficial effects of green tea extract.