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Updated: Jun 26, 2026
Neurodevelopmental Reflex Testing in Neonatal Rat Pups
Published on: April 24, 2017
Effects of neonatal dexamethasone or methylprednisolone on rat growth and neurodevelopment
Ilknur Kilic1, Erol Dagdeviren, Ertugrul Kaya
1Department of Pediatrics, Pamukkale University Faculty of Medicine, Denizli, Turkey.
Insights
Neonatal dexamethasone and methylprednisolone exposure significantly impacts rat pup growth and neurodevelopment. Methylprednisolone appears to be a safer alternative to dexamethasone for neonatal treatment.
Area of Science:
- Neonatal pharmacology
- Developmental neuroscience
- Pediatric clinical research
Background:
- Long-term dexamethasone therapy in premature infants is linked to impaired growth and smaller head circumferences.
- Understanding the differential effects of neonatal corticosteroids is crucial for optimizing infant care.
Purpose of the Study:
- To compare the effects of equivalent anti-inflammatory doses of neonatal dexamethasone and methylprednisolone on rat growth and neurodevelopment.
- To evaluate potential safety differences between these two corticosteroid treatments in a preclinical model.
Main Methods:
- Rat pups were administered tapering doses of dexamethasone, methylprednisolone, or saline from postnatal day 3 to 6.
- Body weight, length, and neurological responses were systematically recorded and analyzed on multiple postnatal days.
- Physical development was assessed through standardized neurological and developmental tests.
Main Results:
- Both dexamethasone and methylprednisolone groups exhibited reduced weight compared to controls, with dexamethasone showing the most significant reduction.
- Dexamethasone-treated pups displayed significantly shorter body length and lower neurological scores throughout the study period.
- While methylprednisolone also impacted early neurological scores, recovery was observed by postnatal day 21.
Conclusions:
- Neonatal methylprednisolone treatment may offer a safer profile compared to dexamethasone regarding growth and neurodevelopmental outcomes.
- These findings suggest that methylprednisolone could be a preferred alternative in clinical settings where neonatal corticosteroid therapy is necessary.
Background:
Clinical studies have demonstrated that premature infants receiving long-term dexamethasone therapy have reduced linear growth, decreased weight gain, and smaller head circumferences. The purpose of the present study was to investigate the effects of the same equivalent doses for anti-inflammatory potency of neonatal dexamethasone and methylprednisolone on rat growth and neurodevelopment.
Methods:
The pups were randomly separated into three treatment groups on postnatal day (PD) 3. At postnatal 3-5 days, tapering doses of corticosteroids or sterile saline were administered subcutaneously. Group 1 was the dexamethasone group (n = 12; PD 3, 0.5 mg/kg; PD 4, 0.25 mg/kg; PD 5, 0.125 mg/kg; PD 6, 0.05 mg/kg s.c.); group 2, methylprednisolone group (n = 12; PD 3, 2.6 mg/kg; PD 4, 1.3 mg/kg; PD 5, 0.650 mg/kg; PD 6, 0.325 mg/kg; group 3, control group (n = 12; normal saline injected). Weight was recorded on PD 3-6, 8, 14, 22, length was recorded on PD 3, 7, 14, 21 for each group. Neurological responses and physical development were tested on PD 7, 14, 21.
Results:
On PD 4-6, 8, 14, 22 the weight in the dexamethasone and methylprednisolone groups was lower than in the control group, but the weight in the dexamethasone group was the lowest (P < 0.05). The length in the dexamethasone group was significantly shorter than in the methylprednisolone group on PD 14 and 21. Dexamethasone-treated animals had a reduced total neurological score compared with the methylprednisolone and control groups on PD 7, 14, 21. Although methylprednisolone-treated animals had lower total neurological score than that of the control group on PD 7 and PD 14 (P < 0.05), total neurological scores were not different in the methylprednisolone and control groups on PD 21.
Conclusions:
Postnatal methylprednisolone treatment might be safer than dexamethasone treatment in newborns.
