Table 2.

Semi-quantitative analysis of fibrosis in the heart of the 7.0 mg/kg and 6.0 mg/kg MTX-treated and respective controls groups, in adult and infant animals.

Sirius Red Staining
	INFANT		ADULT
	Control	MTX 7.0 mg/kg	Control	MTX 7.0 mg/kg
% area ratio of collagen/skeletal muscle	0.14 ± 0.07	0.17 ± 0.05	0.14 ± 0.02	0.24 ± 0.06 ****
	Control	MTX 6.0 mg/kg	Control	MTX 6.0 mg/kg
% area ratio of collagen/skeletal muscle	0.10 ± 0.03	0.15 ± 0.03	0.10 ± 0.02	0.16 ± 0.05 **

Results of Sirius red staining, given in area of collagen/skeletal muscle, are presented as mean ± SD and were obtained from 3 animals from each treatment group. Statistical comparisons were made using the Mann–Whitney test: ** p < 0.01, **** p < 0.0001, MTX vs. control.