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Updated: Jun 6, 2026
Neurobehavioral Assessments in a Mouse Model of Neonatal Hypoxic-ischemic Brain Injury
Published on: November 24, 2017
Comparing neuroprotective drug efficacy in rodent neonatal brain injury models
John D E Barks1, Yiqing Liu2, Julie Sturza2
1Department of Pediatrics, University of Michigan Medical School, The University of Michigan, Ann Arbor, MI, USA. jbarks@med.umich.edu.
Background:
A challenge in preclinical neonatal neuroprotection research is the implementation of study designs that enable direct comparison of multiple potentially effective drugs. We used adaptive design to test four FDA-approved drugs (azithromycin, erythropoietin, caffeine, and melatonin) concurrently and determine which best combined safety and efficacy.
Methods:
Seven-day-old (P7) rats underwent hypoxia-ischemia (HI; right carotid ligation + timed 8% O2 exposure); some experiments included pre-treatment with agents that induced inflammation, and some included post-HI brief moderate hypothermia. Sensorimotor and neuropathology measures were incorporated into a Composite Score that also accounted for deaths. Outcome was initially evaluated at P21 and in confirmatory studies at P35. A pre-specified Bayesian algorithm with futility and efficacy stopping rules was devised to analyze emerging data and adjust subsequent animal allocation among drug groups.
Results:
In all models, either azithromycin or erythropoietin (EPO) offered superior neuroprotection at P21, and the other was "runner-up". Caffeine and melatonin conferred modest neuroprotection in pure HI but were quickly eliminated in hypothermia-treated HI. At P35, azithromycin and EPO outcomes were generally similar.
Conclusion:
These results support azithromycin as a candidate neuroprotective agent that warrants future studies in large animal neonatal cerebral hypoxia-ischemia models.
Impact:
We used adaptive design to compare four repurposed drugs (azithromycin, caffeine, erythropoietin, and melatonin) in neonatal rodent brain injury. Key factors differentiating our approach from existing reports were within-litter comparisons, evaluation in multiple models, and measurement of both function and neuropathology. Either azithromycin or erythropoietin was the most neuroprotective in any given model, with the other a close "runner-up". Melatonin and caffeine were neuroprotective in pure HI, but less effective than azithromycin. In other models, they were less effective and eliminated early by the Bayesian algorithm. This supports azithromycin as a candidate neuroprotectant and supports future studies in large animal models.
Insights
Azithromycin and erythropoietin demonstrated superior neuroprotection in neonatal rodent brain injury models. This adaptive study design efficiently compared repurposed drugs for potential clinical use.
Area of Science:
- Neonatal neuroscience
- Pharmacology
- Preclinical research
Background:
- Neonatal neuroprotection research faces challenges in comparing multiple drugs simultaneously.
- Adaptive study designs offer a solution for efficient preclinical drug evaluation.
Purpose of the Study:
- To compare the safety and efficacy of four FDA-approved drugs (azithromycin, erythropoietin, caffeine, melatonin) for neonatal brain injury.
- To identify the most effective neuroprotective agent using an adaptive design.
Main Methods:
- Seven-day-old rats underwent hypoxia-ischemia (HI) with varying pre-treatments and hypothermia.
- A composite score assessed sensorimotor function, neuropathology, and survival.
- A Bayesian adaptive algorithm adjusted animal allocation based on emerging data.
Main Results:
- Azithromycin and erythropoietin (EPO) showed superior neuroprotection in most models.
- Caffeine and melatonin were less effective, especially in hypothermia-treated HI models.
- Outcomes for azithromycin and EPO were similar at P35.
Conclusions:
- Azithromycin is a promising neuroprotective candidate for neonatal hypoxia-ischemia.
- Further studies in large animal models are warranted to validate azithromycin's efficacy.
