Abstracts

Rationale: Undernourishment is responsible for serious physiological and morphological changes on the developing central nervous system. During brain development, the first year of life is the most important period and whatever happens at this time will have indelible repercussions later in life. Undernourishment is not a direct cause of epilepsy but it is known that it might diminish the threshold for seizures induction. In fact, prenatal and lactation malnutrition affects spatial memory in rats. Indeed, studies with experimental animals have confirmed that recurrent or prolonged seizures can lead to a variety of adverse effects on memory and behavior In this study we evaluated the effects of undernourishment and seizures on memory and spatial learning in a model of developing brain. Methods: Male Wistar pup rats were allocated to one out of six experimental groups as follows: Nourished Control (NC), Nourished Recurrent Seizures (NRS), Nourished Status Epilepticus (NSE), Undernourished Control (UC), Undernourished Recurrent Seizures (URS) or Undernourished Status Epilepticus (USE). UC, URS and USE groups were maintained on a starvation regimen from post-natal day 2 (P2) to post-natal day 15 (P15). URS and NRS groups suffered three daily flurothyl-induced seizures from P2 to P4. USE and NSE groups suffered a status epilepticus (SE) at P15. Beginning at P21 all groups were trained in the Morris water maze. At P30 the animals were sacrificed and their brains weighted. 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)(figure 1). Conclusions: Data from this experiment shows that undernourishment, that happened between the second (P2) and the fifteenth (P15) day of life of the pups, diminished body and brain weights as well as damaged their spatial memory, without lowering seizures threshold by the flurothyl model. However we found out that despite undernourishment and seizures have a detrimental additive effect on both, body weight and spatial memory, brain weight from the rats that suffered undernourishment and seizures were higher than of those animals who were undernourished but seizure-free and that could be explained by a possible brain edema. The most important aspect that we conclude by this experiment is that undernourishment, as well as status epilepticus and recurrent seizures have a detrimental effect on spatial memory of pup rats and that the group that showed the worst spatial memory acquisition was the one that suffered undernourishment and status epilepticus. Grants from FAPERGS and CNPq (05/2247.6 and 478065/2006-0).