Fig. 3. Knockout of Nrf2 aggravates invertebral disc (IVD) degeneration and reduces autophagy genes expression in induced mouse model of IVD degeneration.

a Analysis of extracellular matrix composition by Safranin O staining of sections from IVDs in WT and Nrf2-KO mice after puncture (Model) or sham-operation. b Histological degenerative scores of IVDs in WT and Nrf2-KO mice after puncture (Model) or sham-operation. Histological changes were observed by hematoxylin and eosin (HE). c Expression levels of the autophagy genes from the NP tissues in WT and Nrf2-KO mice after puncture (Model) or sham-operation were determined by qRT-PCR. Data are mean ± SD (n = 5). Statistical analysis was performed with the Student’s t test. *,#p < 0.05; **p < 0.01; * vs. WT-Sham, # vs. WT-Model. d Western blotting for the protein levels of SQSTM, Atg5, Atg7, and HO-1