Impact of Early- and High-Dose Caffeine on the Cerebellum Development in Newborn Rats

Abstract

<b><i>Introduction:</i></b> Preterm newborns struggle with maintaining an adequate respiratory pattern; early caffeine administration is suggested to stimulate respiration and reduce bronchopulmonary dysplasia, however, its consequences on the immature cerebellum remains unknown. This study aimed to assess the impact of early caffeine administration, at standard and high doses, accompanied by supplemental oxygen on cerebellar development in an experimental model. <b><i>Methods:</i></b> Five groups of Wistar pups were formed (<i>n</i> = 8 offspring/group): (a) negative control: no intervention; (b) placebo: pups remaining from birth until the 7th day of life (DOL) exposed to fractional inspired oxygen (FiO₂) 45%, resembling preterm infant condition and as a placebo, 0.2 mL oral 5% dextrose, from the first DOL until the 14th DOL; (c) caffeine group: oral caffeine, 1st DOL 20 mg/kg, and from 2nd to 14th DOL, 5 mg/kg (standard dose); (d) caffeine at the standard dose, plus O₂: during the first 7 DOLs (FiO₂: 45%); (e) caffeine: 40 mg/kg in the first DOL, 10 mg/kg the next 14 DOLs, plus O₂ in the first 7 DOLs (FiO₂: 45%). Subjects were sacrificed on their 15th DOL; measurements were taken from the cerebellum, specifically the external granular layer (EGL) and molecular layer (ML), with quantification of cell migration. <b><i>Results:</i></b> Caffeine administration in pups resulted in a delay in cerebellum development based on persistent transitional EGL cells; this finding was exacerbated in groups exposed to caffeine plus O₂, as evident from the thicker EGL. The negative control group showed near-complete cell migration with a thicker ML and a significantly smaller EGL. <b><i>Conclusions:</i></b> Early caffeine administration in newborn rats disrupts cerebellar cortex cell processes and connectivity pathways, with exacerbated effects in groups receiving caffeine plus O₂.