Fig. 4

Knockdown of HOTAIR attenuates IL-1β-induced human NP cell senescence, apoptosis, and ECM degradation. a RT-qPCR analysis of HOTAIR expression in NP cells. b RT-qPCR analysis of MMP-3, MMP-9, MMP-10, type II collagen, and aggrecan expression in NP cells. c Protein expression levels (cleaved caspase-3, Bcl-2, Bax, p16, and p53) as analyzed by western blot. d Histogram showing the relative protein expression levels of cleaved caspase-3, Bax, p16, and p53 in the four groups. e An MTT assay was performed to measure the proliferation of NP cells following plasmid transfection and IL-1β treatment. f Flow cytometric distributions of apoptosis and cell cycle phases of NP cells after plasmid transfection and IL-1β treatment. g Immunofluorescence staining of MMP-9 in NP cells from different groups. Data are presented as mean ± SD from 3 samples for each group in 3 independent experiments. Data were analyzed using Student’s t-test. *P < 0.05 vs. control group. ^#P < 0.05 vs. siScr + IL-1β group