Chang et al. (2017) reported extensive lung fibrotic injury in histological investigation and enhanced content of hydroxyproline, collagen types I and III in rat lung tissue exposed to nano-nickel oxide (NiO, 0.015, 0.06, and 0.24 mg/kg; 6 weeks). This study suggested that PF induction by NiO-NPs may be related to TGF-β1 activation. Carbon black nanoparticles (5 mg/m3 and 30 mg/m3; 14, 28, and 90 days) also induced PF in rats, which might be linked with persistent lung inflammation through NLRP3 inflammasome activation (Zhou et al., 2020). This evidence concerns the gene NLRP3 and pemphigus foliaceus.