Effects of Inhaled Corticosteroids on the Growth Plates of Infant Rats

Area of Science:

• Pediatric Endocrinology
• Pharmacology
• Developmental Biology

Background:

• Inhaled corticosteroids (ICS) are widely used for pediatric respiratory conditions.
• Potential adverse effects include hypothalamic-pituitary-adrenal axis suppression and growth retardation.
• The specific impact of different ICS on growth plate development requires further investigation.

Purpose of the Study:

• To evaluate the effects of inhaled budesonide and fluticasone propionate on the growth plates of infant rats.
• To compare the dose-dependent inhibitory effects of these corticosteroids on key growth plate parameters.

Main Methods:

• Infant rats (10 days old) were administered low and high doses of budesonide and fluticasone propionate (50-250 mcg/day) for 10 days.
• Tibias were analyzed using immunohistochemical staining to assess chondrocyte proliferation, apoptosis, IGF-1, and glucocorticoid receptor levels.
• Measurements of resting, proliferative, hypertrophic, and total growth plate zones were compared between treatment groups.

Main Results:

• High-dose fluticasone propionate (250 mcg) demonstrated a significantly greater inhibitory effect on growth plate parameters compared to high-dose budesonide (p = 0.01).
• Fluticasone significantly impacted chondrocyte proliferation, apoptosis rates, IGF-1, and glucocorticoid receptor levels.
• All measured growth plate zones (resting, proliferative, hypertrophic, total zone) were negatively affected by high-dose fluticasone.

Conclusions:

• Fluticasone propionate, particularly at higher doses, exhibits a more pronounced negative impact on the developing growth plate compared to budesonide.
• These findings highlight the potential for specific inhaled corticosteroids to inhibit longitudinal bone growth in pediatric populations.
• Further research is warranted to elucidate the long-term consequences and clinical implications of these observed effects.