Table 3.

Characteristics of the studies evaluating the effect of RA on pulmonary fibrosis.

Author	Year	Type of animal/cells	Weight of animal/Age	Type of RA	Dose of RA	Effect
Tabata et al.	2006	C57BL/6 mice	Eight-week-old	ATRA	0.5 mg/mice, repeated three times weekly	+
		Lung fibroblasts	–	ATRA	1 μM	+
Esteban-Pretel et al.	2010	Wistar rats	60-day-old	ATRA	100 μg/rat, 10 consecutive days	+
Ozer et al.	2005	Wistar rats	Postnatal day 3	ATRA	500 ug/kg, 10 consecutive days	+
Tabata et al.	2005	C57BL/6 mice	Eight-week-old	ATRA	0.5 mg/mice, repeated three times weekly	+
		Lung fibroblasts	–	ATRA	1 μM	+
Dong et al.	2012	C57BL/6 mice	18–22 g	ATRA	Repeated 3 times weekly, for 28 days	+

Note: RA = retinoic acid; ATRA = all-trans retinoic acid; Effect +: RA plays a protective role against pulmonary fibrosis/extracellular matrix accumulation.