[Effects of febrile seizures on motor, behavior, spatial learning and memory in rats]

Febrile seizure is a very common emergency in children. Although researchers home and abroad constantly pay close attention to studies on brain damage and lesion possibly caused by febrile seizure, studies of effects on motor, behavior, spatial learning and memory are relatively seldom. In our study, Sprague-Dawley rats were utilized for the purpose of the exploration of effects of febrile seizures on their motor, behavior, spatial learning and memory.

Sixty 21-day-old male Sprague-Dawley rats, weighing (50 +/- 5) g were divided randomly and equally into febrile seizure group (FS), febrile control group (FG) and normal control group (NG). Febrile seizure animal model was induced by hyperthermal bath with 45 degrees C water. Febrile seizure was induced twice a day, thus ten times within five days in FS group. Rats of FG group were immersed in the same hyperthermal water for 2 minutes. Nothing special was performed on NG group. The abilities of motor and behavior of every rat in these 3 groups were tested in inclined plane test (IPT), overhanging test (OHT) and open field test (OFT) to show their varieties. Furthermore, Morris water maze was applied to evaluate the effects by febrile seizure on spatial learning and memory in rats during the place navigation test and spatial probe test.

In the present experiments, febrile seizures were altogether induced 192 times with the mean latency being (4.25 +/- 0.98) minutes and the mean duration being (1.06 +/- 0.59) minutes. The experiments confirmed that multiple febrile seizures could lead to decreases of abilities in all tests in which analysis of variance indicated that there were significant differences between febrile seizure group and the other two (P < 0.01). In inclined plane test, the turning ability of the rats was weakened. The mean turning time was (9.1 +/- 2.6) seconds for FS, (5.3 +/- 2.1) seconds for FG and (5.3 +/- 2.0) seconds for NG. In overhanging test, the overhanging time was shortened: (33.4 +/- 18.1) seconds for FS, (50.1 +/- 20.3) seconds for FG and (59.0 +/- 20.7) seconds for NG. In the open field test, the rats became less active with the scores (5.1 +/- 2.0) for FS, (10.4 +/- 3.0) for FG and (13.2 +/- 2.3) for NG. Meanwhile, the authors discovered the decreases of the abilities of spatial learning and memory in rats caused by febrile seizures many times. In the place navigation test, the mean escape latency for the rats' looking for hidden platform was prolonged; the efficiency of their search strategy decreased; the swimming time the animals spent in platform region decreased [(44.02 +/- 5.25) seconds for FS, (51.75 +/- 5.28) seconds for FG and (57.07 +/- 5.36) seconds for NG; analysis of variance, P < 0.01.]; the number of times they crossed the platform area decreased [(6.07 +/- 1.77) times for FS, (9.25 +/- 2.07) times for FG and (11.34 +/- 2.37) times for NG; analysis of variance, P < 0.01]; the percentage of their swimming time fell (36.68% for FS, 43.13% for FG and 47.56% for NG).

The experiments confirmed that multiple febrile seizures could result in damage and lesion of motor, behavior, spatial learning and memory in rats.