Zinc inhibits H(2)O(2)-induced MC3T3-E1 cells apoptosis via MAPK and PI3K/AKT pathways.

Zinc has been shown to increase bone mass and promote bone cell proliferation and differentiation. We, therefore, hypothesized that zinc might be cytoprotective for bone cells during oxidative stress. The cells were divided into H(2)O(2), zinc and zinc+H(2)O(2) groups. In the present study, zinc was found to inhibit H(2)O(2)-induced apoptosis in MC3T3-E1 cells, as shown by analysis of Annexin V/PI double staining. Western blot data showed that in zinc+H(2)O(2)-treated cells, zinc decreased the levels of AIF, Bax and active caspase-9 and -3, which are pro-apoptotic factors. And zinc inhibited release of cytochrome c from mitochondria to cytosol in zinc+H(2)O(2)-treated cells. Further investigation shows that protection is via activation of PI3K/Akt/mTor and MAPK /ERK pathways and inhibition of MAPK/P38 and MAPK/JNK pathways. Protecting osteoblast cells from oxidative damage presents a potential application in the treatment of osteoporosis.