PPAR-γ Activation Alleviates Osteoarthritis through Both the Nrf2/NLRP3 and PGC-1α/Δψ_m Pathways by Inhibiting Pyroptosis

Figure 5

Piog partially attenuates LPS/ATP-induced pyroptosis of chondrocytes through the PGC1-α/Δψ_m signaling pathway. (a) PPAR-γ activation by Piog rescued PGC1-α expression in the presence of LPS/ATP. Western blot analysis for PGC1-α in the control, LPS/ATP, Piog + LPS/ATP, and Piog + GW + LPS/ATP groups. (b) Cells were pretreated with Piog in the presence or absence of SR and then stimulated with LPS/ATP. The level of NLRP3 was detected using western blotting. (c) ELISA was performed to measure IL-1β and IL-18 levels in the control, LPS/ATP, Piog + LPS/ATP, and Piog + SR + LPS/ATP groups. (d) CCK8 assays were performed to determine the chondrocyte viability in the control, LPS/ATP, Piog + LPS/ATP, and Piog + SR + LPS/ATP groups. (e) The intracellular ROS content was detected in the same five groups using Δψ_m assays. (f and g) The ratio of red fluorescent emission of cells with intact Δψ_m against green fluorescent emission of cells with impaired Δψ_m was plotted to represent the changes in Δψ_m. Fluorescent spectrophotometry was used to detect the Δψ_m of JC-1-stained cells in the control, LPS/ATP, Piog + LPS/ATP, GW + Piog + LPS/ATP, and SR + Piog + LPS/ATP groups (bar: 100 μm). GAPDH was used as an internal reference for western blotting. The characteristic immunoblot pictures are located under their densitometric analysis. The data represent three independent experiments and are expressed as mean ± SD. **.

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