Related Experiment Video
Updated: Apr 16, 2026
Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia
Published on: October 25, 2016
Sex-related differences in effects of progesterone following neonatal hypoxic brain injury
Bethany L Peterson1, Soonmi Won1, Rastafa I Geddes1
1Department of Emergency Medicine, Emory University, Atlanta, GA 30322, USA.
Insights
Progesterone shows neuroprotective effects in male neonatal rats with hypoxic-ischemic encephalopathy, reducing tissue damage and inflammation. This study highlights sex differences in brain injury response and potential therapeutic benefits.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Neonatal hypoxic-ischemic (HI) encephalopathy lacks effective treatments.
- Progesterone is effective for adult traumatic brain injury but unstudied in neonates.
Purpose of the Study:
- Investigate progesterone's neuroprotective effects in neonatal HI brain injury.
- Evaluate sex-specific responses to progesterone treatment.
Main Methods:
- Neonatal rats underwent unilateral carotid artery ligation and hypoxia.
- Progesterone was administered post-injury, followed by tissue and behavioral analysis at six weeks.
- Evaluated lesion size, inflammatory factors, neurological reflexes, motor asymmetry, and cognitive performance.
Main Results:
- HI-injured male rats treated with progesterone showed significant long-term tissue protection compared to controls.
- Progesterone reduced activated microglia in male HI-injured rats.
- Both sexes showed modest behavioral benefits, with substantial sex differences observed.
Conclusions:
- Progesterone demonstrates neuroprotective potential in neonatal HI encephalopathy, particularly in males.
- Significant sex differences exist in neuroprotection and behavioral outcomes.
- Immature male and female brains respond differently, necessitating separate analyses.
Abstract:
There is no satisfactory therapeutic intervention for neonatal hypoxic-ischemic (HI) encephalopathy. Progesterone is known to be effective in treating traumatic brain injury in adult animals but its effects in neonatal brains have not been reported. Brain injuries were induced by a unilateral common carotid artery ligation plus hypoxia exposure. Progesterone was administered immediately after hypoxia and daily for 5 days at 8 mg/kg, followed by a tapered dose for two days. At six weeks post-injury, lesion size and inflammatory factors were evaluated. Progesterone-treated, HI-injured male animals, but not females, showed significant long-term tissue protection compared to vehicle, suggesting an important sex difference in neuroprotection. Progesterone-treated, HI-injured male rats had fewer activated microglia in the cortex and hippocampus compared to controls. The rats were tested for neurological reflexes, motor asymmetry, and cognitive performance at multiple time points. The injured animals exhibited few detectable motor deficits, suggesting a high level of age- and injury-related neuroplasticity. There were substantial sex differences on several behavioral tests, indicating that immature males and females should be analyzed separately. Progesterone-treated animals showed modest beneficial effects in both sexes compared to vehicle-treated injured animals. Sham animals given progesterone did not behave differently from vehicle-treated sham animals on any measures.
