FIGURE 6.

Inhibition of MAPK and depletion of PGE₂ from FF-CM attenuates the inhibitory effect of PGE₂ or FF-CM on hemichannel opening in response to FFSS. A, MLO-Y4 cells were treated with 1 nm PGE₂ for 24 h and then with or without U0126 for 30 min before subjecting cells to FFSS for 30 min or non-FFSS control. B, primary mouse osteocytes were treated with 1 or 100 nm PGE₂ for 24 h and then with or without U0126 for 30 min before subjecting cells to FFSS for 30 min or non-FFSS control. C, MLO-Y4 cells were treated with FF-CM (collected after 24 h of FFSS) or FF-CM depleted of PGE₂ (CM(-PGE₂)) for 24 h before subjecting the cells to FFSS for 30 min or non-FF control. LY dye uptake assay was performed and quantified. All the data are presented as mean ± S.E., n = 3. ***, p < 0.001; **, p < 0.01; *, p < 0.05.