# Effects of Epigallocatechin-3-O-Gallate on Bone Health
## 3 Biochemical Effects of EGCG
### Increasing Expression of the OSL  
OSX is an osteoblast-specific transcription factor required for bone formation [85; 86; 87; 88]. It activates a repertoire of genes during the differentiation of preosteoblasts into mature osteoblasts and osteocytes and decreases osteoblast proliferation [85]. There are two main pathways through which _Oss_ gene expression is induced: directly or indirectly [89]. RUNX2 plays a key role during bone development by directly initiating the expression of other osteogenic genes, such as _Alp_ and _Col1_ in the early stage and _Opn_ and _Ossx_ in the later stage [90]. For the RUNX2-dependent pathway, OSX inhibits chondrocyte differentiation in \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Ref.**} & \multicolumn{2}{c}{**Effects**} & \multirow{2}{*}{**Functional Changes and Methodology**} & \multirow{2}{*}{**Cell Culture Data**} \\  & & & & \\ \cline{3-4} \cline{6-5}  & **Influence** & **EGCG Conc.** & & \\ \hline \multirow{8}{*}{[48]} & Increase in osteoblast & \multirow{8}{*}{SoS-2} & Protein changes: & Solvent; PBS, EGCG directly dissolved in \\  & differentiation and decrease in & RUNX2 protein levels & RUNX2 protein level analysed by Western blot. & culture medium \\  & RUNX2 protein levels & No change at 62 kDa significant decrease & Costogenic substrate/status: \\  & Increasing the formation of & \multirow{8}{*}{5 uM} & (-65 uK) reduction at 48 kDa with 5 uM of EGCG & Cells cultured in [PERSON]’s F-12 medium with FRS, \\  & HOB-like cells by enhancing & & relative to control & dexamethasone, ascorbic acid. \\  & osteoblastic differentiation & & & \(\beta\)-glycerophosphate (added to induce \\  & & & & mineralisation) \\ \hline \multirow{8}{*}{[33]} & Increasing ALP & \multirow{8}{*}{\begin{tabular}{} \end{tabular} } & \multirow{8}{*}{\
\begin{tabular}{} \end{tabular} } \\  & activity/mineralisation and & & & \\ \cline{3-4} \cline{6-5}  & increasing the expression of the & \multirow{8}{*}{hBM-MSCs} & \multirow{8}{*}{
\begin{tabular}{} \end{tabular} } \\  & RUNX2 and OSL & & & \\ \cline{3-4} \cline{6-5}  & Preventing TNF\& inhibition of & and more aligned those/SCC.Get at low doses & \\ \cline{3-4} \cline{6-5}  & survival and osteogenic & & & \\ \cline{3-4} \cline{6-5}  & differentiation of human & \multirow{8}{*}{5 uM} & (Sand 10 uM reversed TNF-induced & \(\beta\)-glycerophosphate, dexamethasone, ascorbic \\  & hBM-MSCs (at low conc. & & suppression, restoring mRNA levels close & acid 2-phosphate \\  & of EGCG) & to control & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: EGCG influence on the RUNX2 protein level. RUNX2-expressing precursor osteoblasts. RUNX2 expression is initially detected in pre-chondrogenic mesenchymal cells. As development progresses, OSX expression is induced, leading to the differentiation of RUNX2-positive cells into osteoblast precursors [86; 87]. In both membranous and endochondral skeletons, OSX-null preosteoblasts are unable to differentiate into osteoblasts, which means that without OSX, mature osteoblasts are not formed [85]. Moreover, OSX inhibits the Wnt pathway [85; 87]--a RUNX2-independent pathway. The Wnt pathway modulates bone formation through the control of progenitor cell proliferation and differentiation [87]. The influence of EGCG on the expression of OSX was examined in many in vitro studies, with consistently positive effects observed across various cell types (Table 3). In D1 murine mesenchymal stem cells, EGCG enhanced osteogenic differentiation by upregulating osteogenic gene expression, which included increased OSX levels [26]. In hPDLCs, EGCG significantly elevated both the mRNA and protein expression of OSX, indicating its direct role in promoting osteogenesis [29]. Similarly, in hBM-MSCs, low concentrations of EGCG stimulated OSX expression while protecting against the TNF\(\alpha\)-induced inhibition of osteogenic differentiation [33]. In hBM-MSCs, EGCG reversed oxidative damage induced by H\({}_{2}\)O\({}_{2}\), leading to a marked increase in OSX expression and enhanced mineralization capacity [40].