Table 1.

Effect of Metformin administration on lung histopathology in the late stage

Groups	Lesion severity grade						Average severity grade	Lesion distribution grade						Average distribution grade
	0	1	2	3	4	5		0	1	2	3	4	5
Saline	6						–	6						–
Silica				1	2	3	4.33 ± 0.33			1	1	3	1	3.67 ± 0.42
Silica + 100 mg/kg metformin		2			4		3.67 ± 0.84		2	4				1.67 ± 0.21a
Silica + 300 mg/kg metformin	1	3	1			1	1.67 ± 0.71a	1	4	1				1.00 ± 0.26a

Values represent the means ± SD of 6 for each group

^ap < 0.05 vs. silica group (independent-sample t-test)