Excessive maternal caffeine exposure during pregnancy is cataractogenic for neonatal crystalline lenses in rats: a biomicroscopic and histopathologic study

Abstract

Purpose: To investigate histologically the influence of maternal caffeine exposure during pregnancy in vivo on crystalline lenses in neonatal rats.

Methods: Experimentally naive, female Wistar-albino rats (200-220 g) were mated with adult male rats over 2 days for copulation. After confirming pregnancy with a vaginal smear method, 50 gravid rats (dams) were randomly divided into five groups (n = 10 in each), consisting of one control and four experimental groups. Groups 1, 2 and 3 experimental dams were treated with intraperitoneal (i.p.) caffeine at doses of 25, 50 and 100 mg/kg/day, respectively, during pregnancy from gestational day 9 through to day 21. Group 4 dams were treated with caffeine in distilled water in a gavage at a dose of 50 mg/kg/day. Group 5 control dams were given i.p. saline solution daily for the same period. After normal delivery, the eyes were examined by slit-lamp biomicroscopy. The neonates were then killed by decapitation at postnatal days 1 or 30 and the eyes removed for histopathologic investigation of the lenses.

Results: Group 1 and control eyes had normal anterior lens capsules with a single layer of anterior cuboidal epithelial cells, regularly oriented cortical and nuclear lens fibres, and a clear posterior lens capsule with no lining epithelial cells behind the equator. In the remaining groups, histopathologic findings suggesting cataractogenesis included eosinophilic degeneration, lens fibre cell swelling and liquefaction, central lens fibres with retained nuclei, and prominent epithelial cells lining the posterior lens capsule behind the equator. Moreover, some lenses in group 3 had immature cataract on slit-lamp biomicroscopic examination at postnatal day 30.

Conclusion: Excessive maternal caffeine exposure during pregnancy had cataractogenic effects on developing crystalline lenses in newborn rat eyes, both macroscopically and histopathologically. If an appropriate dose of caffeine can be identified, caffeine-induced cataract formation may be used as a new experimental cataract model in animal studies.