Figure 7. HDAC4 overexpression abates the damage-boosting function mediated by ZIP4 overexpression. (A) NP cells were transfected with the sh-NC or sh-HDAC4 overexpression plasmid. Western blot confirmed the transfection efficiency. The HDAC4 overexpression plasmid and ZIP4 overexpression plasmid were cotransfected into NP cells, which underwent 20 ng/ml IL-1β treatment for a 24-hour period in the following step. (B) The LDH level in NP cells treated with IL-1β. (C, D) The profiles of inflammatory factors in the cells verified by ELISA. (E) COX2 and iNOS profiles in the cells checked via western blot. (F–H) MDA, SOD, and ROS levels in the cells were detected. Scale bar=100 μm. (I) MMP-3, MMP-13, collagen II, and aggrecan profiles in the cells examined by western blot. (J) Western blot verified HDAC4, FoxO3a, Sirt1 and NF-κB profiles in NP cells undergoing IL-1β treatment. N=3. **P<0.01, ***P<0.001 (vs. CON); +P<0.05, ++P<0.01, +++P<0.001 (vs. IL-1β); #P<0.05, ##P<0.01, ###P<0.001 (vs. ZIP4+IL-1β).