Histological Changes in Developing Lungs of Albino Mouse on Treatment with Retinoic Acid

Aim: To assess the impact of excessive use of retinoic acid on fetal lung. Methods: Female albino mice were mated to get conceived and were divided into two groups (A and B) of 6 each; group A was a control and those in group B was treated with retinoic acid (RA) 60mg/kg/day on 7.0, 8.0 and 9.0 days of pregnancy. Mice were sacrificed on 19th day of gestation, the fetuses were dissected; their lungs were removed for gross and microscopic study. Results: The comparison of dead and alive fetuses was found to be significant between the groups (p value <0.05). In addition, the histological examination of lungs in group B showed severe hypoplasia with underdeveloped bronchial passages, reduced size of the sacculi, and increased thickness of their wall; when compared to controls, the difference between the groups was statistically significant. Conclusion: The result is suggestive of retinoic acid being responsible to induce morphological changes in the lung architecture when taken during early pregnancy to the extent of even resulting in neonatal deaths. It is therefore pointed out that it may be used with caution in early pregnancy.