Table 1.

Correlation co-efficients (r² values) for the relationship between silica-induced pulmonary toxicity (BALF LDH, PMN and MCP-1) and the number of significantly differentially expressed genes in the lungs and blood of silica exposed rats. The toxicity measurements and the number of differentially expressed genes in the silica exposed rats at postexposure time intervals of 0, 1, 2, 4, 8, 16, and 32 weeks following a one week exposure were used to determine the correlation co-efficients (r² values). The 32-week data were obtained from the present study while data for all other post-exposure time intervals were obtained from our previous publications (Sellamuthu et al., 2011a, 2012).

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

BALF, bronchoalveolar lavage fluid; LDH, lactate dehydrogenase, PMN, polymorphonuclear leukocytes; DEG, differentially expressed gene.