MiR-34a-5p enhanced compression-induced NP cell apoptosis and ECM degradation. (a,b) Human NP cells under compression were transfected with miR-34a-5p inhibitor or miR-34a-5p mimic, and RNA levels of miR-34a-5p were measured by qRT-PCR. ⁎⁎p < 0.01 versus control group, ##p < 0.01 versus compression + NC group, n = 3 [Student's t-test]. (c,d) The protein levels of aggrecan, collagen II, MMP-3, MMP-13, Bax, Bcl-2 and c-caspase 3 in human NP cells transfected with miR-34a-5p inhibitor were measured by western blotting. Proteins were normalized to GAPDH expression levels. #p < 0.05 versus compression + NC group, n = 3 [Student's t-test]. (e-f) The protein levels in human NP cells transfected with miR-34a-5p mimic were measured by western blotting. #p < 0.05, ##p < 0.01 versus compression + NC group, n = 3 [Student's t-test]. (g-h) Human NP cells under compression were transfected with miR-34a-5p inhibitor or miR-34a-5p mimic, and the apoptosis rate was detected by Annexin V-APC/7-AAD staining. #p < 0.05 versus compression + NC group, n = 3 [Student's t-test]. Data presented as means with error bars representing standard deviation (SD).