Fig. 1

Pre-activation of hMSCs enhances the efficacy of CM in attenuating mechanical stretch injury. Mechanical stretch induction of NF-κB was reduced by FBS- and XF-cultured MSC CM in comparison with the MEM-α stretch control (a). Pre-activation of both FBS- and XF-cultured MSCs further enhanced the ability of the MSC CM to attenuate NF-κB when compared to naive MSC CM. Mechanical stretch-induced release of IL-8 (b) was ameliorated by both naive CM groups but more significantly so by the pre-activated XF-hMSC CM (b). Mechanical stretch-induced LDH release again was attenuated by all the MSC CM groups, but more so in the pre-activated FBS MSC CM group (c). The decrease in cell viability, as induced by mechanical stretch, was also abrogated by both naive MSC CM treatments but was more enhanced in the pre-activated XF-hMSC CM group (d). ***P < 0.001 versus MEM-α non-stretch control; ^$, ^$$ and ^$$$P < 0.05, 0.01 and 0.001, respectively, versus MEM-α stretch; ^#, ^## and ^###P < 0.05, 0.01 and 0.001, respectively, versus respective naive FBS or XF-hMSC CM. MEM-α non-stretch control, n = 6; MEM-α stretch control, n = 5 or 6; all other groups, n = 2 or 3