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Updated: May 14, 2026
Assessment of Memory Function in Pilocarpine-induced Epileptic Mice
Published on: June 4, 2020
Neonatal immune challenge exacerbates seizure-induced hippocampus-dependent memory impairment in adult rats
Ping Yin1, Zhen Li, Ying-Yan Wang
1Pediatric Department of Qilu Hospital, Shandong University, Jinan, China.
Insights
Neonatal exposure to lipopolysaccharide (LPS) primes microglia, leading to heightened neuroinflammation and worse behavioral outcomes after seizures in adulthood. Minocycline treatment mitigated these effects, suggesting a therapeutic window.
Area of Science:
- Neuroscience
- Immunology
- Developmental Biology
Background:
- Microglia, the brain's resident immune cells, play a critical role in neuroinflammation.
- Neonatal immune challenges may have long-lasting effects on brain development and function.
- Understanding the link between early-life inflammation and later neurological disorders is crucial.
Purpose of the Study:
- To investigate the impact of neonatal lipopolysaccharide (LPS) exposure on microglia activation.
- To determine if neonatal LPS exposure influences neurobehavioral outcomes following seizures in adulthood.
- To evaluate the therapeutic potential of minocycline in mitigating LPS-induced effects.
Main Methods:
- Neonatal male rat pups were injected with LPS or saline on postnatal days 3 and 5.
- Microglia activation was assessed using immunohistochemistry.
- Seizures were induced at postnatal day 45 using kainic acid (KA); neurobehavioral tests (Y-maze, Morris water maze, inhibitory avoidance) were performed.
Main Results:
- Neonatal LPS exposure led to persistent microglia activation into adolescence.
- LPS-treated rats exhibited increased proinflammatory responses and poorer performance in behavioral tasks after KA-induced seizures.
- Minocycline treatment during the neonatal period attenuated neuroinflammation and improved memory deficits.
Conclusions:
- Neonatal immune activation primes the brain, predisposing it to exacerbated behavioral deficits after seizures.
- Priming of microglia by early-life inflammation may underlie these long-term consequences.
- Targeting microglia activation early in life holds therapeutic promise for seizure-related neurological impairments.
Abstract:
Our aim was to examine whether neonatal lipopolysaccharide (LPS) exposure is associated with changes in microglia and whether these alternations could influence later seizure-induced neurobehavioral outcomes. Male pups were first injected intraperitoneally with either LPS or saline on postnatal day 3 (P3) and postnatal day 5 (P5). Immunohistochemical analysis showed that LPS-treated animals exhibited increased microglia activation that persisted into adolescence. At P45, seizures were induced in rats by intraperitoneal injection of kainic acid (KA). Rats treated with LPS neonatally showed significantly greater proinflammatory responses and performed significantly worse in the Y-maze, Morris water maze, and inhibitory avoidance tasks after KA insult. Treatment with minocycline at the time of neonatal LPS exposure to block LPS-induced microglia alternation attenuated the exaggerated neuroinflammatory responses and alleviated memory impairment associated with the KA insult. Our findings suggest that neonatal immune activation can predispose the brain to exacerbated behavioral deficits following seizures in adulthood, possibly by priming microglia.
