Figure 3. ZIP4 upregulation aggravates ECM degradation in NP cells. (A) NP cells transfected with the vector and ZIP4 overexpression plasmids. Western blot experiments were used to check the transfection efficiency. (B) CCK8 assay was used for evaluating cell viability. (C) The cytotoxicity detection kit evaluated LDH release in NP cells following IL-1β treatment. (D, E) TNF-α and IL-6 profiles in the cells verified by ELISA. (F) Western blot showing the expression levels of COX2 and iNOS in the cells. (G–I) MDA, SOD, and ROS levels in the cells were determined. Scale bar=100 μm. (J) MMP-3, MMP-13, collagen II and aggrecan levels in the cells confirmed by western blot. N=3. NS P>0.05, *P<0.05, **P<0.01, ***P<0.001 (vs. vector).