Table 1.

Correlation coefficients (r² values) for the relationship between silica-induced pulmonary toxicity (BALF LDH, PMN and MCP-1) and the number of significantly differentially expressed genes (SDEGs) in the lungs and blood of silica-exposed rats

	BALF LDH	BALF PMN	BALF MCP-1
Lung SDEGs	0.776	0.879	0.927
Blood SDEGs	0.831	0.923	0.958

The toxicity measurements and the number of differentially expressed genes in the silica-exposed rats at post-exposure time intervals of 0, 1, 2, 4, 8, 16 and 32 weeks after a 1-week exposure were used to determine the correlation coefficients (r² values) (reproduced with permission from Inhalation Toxicology 2012: 24: 570–579).