TABLE 1.

Chronic Inflammation and Fibrosis in AhR^−/− Mice

Strain	Wet weight		% Increase	Hydroxyproline		% Increase
	Vehicle	Silica		Vehicle	Silica
C57Bl/6	92.70 ± 9.7	147.57 ± 6.0*	44.81 ± 5.1	18.98 ± 1.6	33.29 ± 2.5*	83.72 ± 12.0
AhR−/−	106.16 ± 2.6	151.19 ± 4.1*	31.54 ± 9.0#	24.62 ± 0.4@	32.50 ± 2.7*	51.58 ± 3.2#

Note. Chronic SiO₂ exposure resulted in increased lung wet weight as well as collagen deposition in the lungs of AhR^−/− and C57Bl/6 mice, although this response was attenuated in AhR^−/− mice compared with wild type. Values are means ± SEM.

^@p < 0.05 compared with wild-type baseline value, *p < 0.05 compared with respective vehicle control, #p < 0.05 compared with percent increase of wild-type mice. n = 5–6.