Fig. 4. TNF-α, IL-6, HO-1 mRNA and protein levels in livers of rats treated with PM2.5. Mean expression of mRNA in each treated group is shown as an increase compared to the mean expression in the control group, which has been ascribed an arbitrary value of 1. The values are mean ± SD from five individual samples. Using one-way ANOVA, compared with the control group, significant difference is indicated by *P < 0.05 and **P < 0.01.
