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Published on: December 4, 2013
Effects of early malnutrition, isolation and seizures on memory and spatial learning in the developing rat
Marta Hemb1, Martin Cammarota, Magda Lahorgue Nunes
1Department of Neurology, Pontificia Universidade Catolica do Rio Grande do Sul, Porto Alegre, Brazil. martahemb@hotmail.com
Insights
Early undernourishment and seizures negatively impact developing rat brains. Both conditions combined worsen body and brain weight and impair spatial memory more than either factor alone.
Area of Science:
- Neuroscience
- Developmental Biology
- Behavioral Neuroscience
Background:
- Undernourishment during development can affect brain structure and function.
- Seizures in early life are a risk factor for cognitive deficits.
- The combined effects of undernourishment and seizures on the developing brain are not fully understood.
Purpose of the Study:
- To investigate the impact of early undernourishment and seizures on memory and spatial learning in a developing rat brain model.
- To determine if undernourishment affects seizure susceptibility.
- To assess the additive or interactive effects of undernourishment and seizures on cognitive function and brain development.
Main Methods:
- Male Wistar rat pups were divided into six groups: nourished controls, nourished with recurrent seizures, nourished with status epilepticus, undernourished controls, undernourished with recurrent seizures, and undernourished with status epilepticus.
- Undernourishment was induced via starvation from postnatal day 2 to 15.
- Seizures were induced using Flurothyl from postnatal day 2 to 4 (recurrent seizures) or on postnatal day 15 (status epilepticus).
- Spatial learning was assessed using the Morris water maze starting on postnatal day 21.
Main Results:
- Early undernourishment reduced body and brain weight but did not alter seizure susceptibility.
- Seizures reduced body weight but not brain weight.
- Undernourished rats and rats experiencing seizures showed impaired performance in the Morris water maze, spending less time in the target quadrant.
- A significant interaction between undernourishment and seizures was observed, indicating an additive detrimental effect.
Conclusions:
- Undernourishment and seizures independently impair spatial memory in developing rats.
- The combination of undernourishment and seizures has an additive negative impact on body weight, brain weight, and spatial memory.
- These findings highlight the vulnerability of the developing brain to combined nutritional and ictal insults.
Purpose:
In this study we evaluated the effects of undernourishment and seizures on memory and spatial learning in a model of developing brain.
Experimental Procedures:
Male Wistar rat pups were allocated to one of six experimental groups: nourished control (NC), nourished recurrent seizures (NRS), nourished status epilepticus (NSE), undernourished control (UC), undernourished recurrent seizures (URS) or undernourished status epilepticus (USE). The UC, URS and USE groups were maintained on a starvation regimen from postnatal day 2 (P2) to postnatal day 15 (P15). URS and NRS groups suffered three daily Flurothyl-induced seizures from P2 to P4. The USE and NSE groups suffered a status epilepticus (SE) on P15. Beginning on P21 all groups were trained in the Morris water maze. At P30 the animals were sacrificed and their brains weighed.
Results:
Our data indicate that early undernourishment does not alter seizure susceptibility at P15, but diminishes body and brain weight (p<0.001), whereas seizures diminish body (p<0.001) but not brain weight (p=0.972). In the Morris water probe test we have observed that undernourished rats spent less time in the target quadrant than nourished animals (p<0.001). Also, rats submitted to recurrent seizures and rats submitted to status epilepticus spent less time in the target quadrant than seizure-free animals (p=0.001). There was a significant interaction between undernourishment and seizure (p=0.013).
Discussion:
Our findings show that undernourishment and seizures have an additive detrimental effect on body and brain weight as well as on spatial memory.
