Table 3. Exposure to PM_2.5 induces expression of fibrosis related molecules in the livers of rats in different groups.

Groups (mg kg–1)	MMP13	Col I	Col III	TGF-β1
	mRNA expressions in livers
0	1.00 ± 0.51	1.00 ± 0.31	1.00 ± 0.32	1.00 ± 0.25
0.2	1.15 ± 0.36	1.29 ± 0.46	1.27 ± 0.26	1.24 ± 0.23
0.6	1.54 ± 0.56	1.33 ± 0.43	1.48 ± 0.38	1.36 ± 0.27
1.5	2.21 ± 0.63**	1.58 ± 0.45*	1.66 ± 0.60*	1.51 ± 0.29*
r	0.99	0.92	0.92	0.91
0.3	1.64 ± 0.59	1.39 ± 0.20	1.50 ± 0.40	1.28 ± 0.44
1.5	2.16 ± 0.43**	1.64 ± 0.57*	1.69 ± 0.23**	1.46 ± 0.40*
2.7	2.33 ± 0.88**	1.78 ± 0.30**	1.71 ± 0.42**	1.62 ± 0.40**
r	0.90	0.91	0.79	0.93

Groups	Protein expressions in livers
0	1.00 ± 0.15	1.00 ± 0.26	1.00 ± 0.26	53.88 ± 17.52
0.2	1.12 ± 0.21	1.46 ± 0.52	1.12 ± 0.16	57.19 ± 22.90
0.6	1.29 ± 0.31	1.73 ± 0.37	1.34 ± 0.55	77.58 ± 21.00
1.5	1.49 ± 0.25*	1.92 ± 0.42*	1.70 ± 0.43*	81.62 ± 26.79*
r	0.98	0.88	0.99	0.89
0.3	1.16 ± 0.13	1.63 ± 0.46	1.19 ± 0.39	56.24 ± 18.26
1.5	1.44 ± 0.28*	1.84 ± 0.46*	1.77 ± 0.43*	67.37 ± 14.40
2.7	1.59 ± 0.17**	2.0 ± 0.38*	1.89 ± 0.31*	86.80 ± 22.80*
r	0.98	0.84	0.95	0.99