Neurobehavioral changes and the prevention effect by melatonin for neonatal rats with recurrent seizures

Objective To explore neurobehavioral changes in rats with recurrent seizures and the prevention effect of melatonin. Methods 6-day-old (P6) SD rats were randomly divided into four groups of 24 (n=6): the control group (CONT), melatonin per se group (MEL), recurrent neonatal seizure group (RS ) and melatonin administration prior to RS group (RS+ MEL). Rats in RS group were subjected to 5 seizures with flurothyl during the first 14 days of life. In RS+ MEL group, melatonin was injected at 8∶00 before seizures were induced.Neurobehavioral tests including Plane righting experiment, Cliff avoidance test, the grip-strength test and negative geotaxis test were implemented on P24, while open field test on P35. Results ⑴ Plane righting experiment: the time of plane righting in RS group ((0.33±0.51)s) was significantly shorter than that in the CONT group ((1.17±0.40)s) and RS + MEL group ((0.50±0.54)s) (P<0.05). (2)Cliff avoidance test: the time of cliff avoidance in RS group ((16.00±6.32)s) was significantly longer than that in CONT group ((4.00±2.60)s) (P<0.01), while the time of cliff avoidance in RS+ MEL group ((7.67±3.26)s) was shorter than that in the RS group (P<0.05). (3)The grip-strength test: compared with CONT group ((49.50±28.96)s), the time needed to hold on wire in RS group((11.67±7.58)s)was significantly shorter (P<0.05) and longer in RS+ MEL group ((24.83±6.61 )s)(P<0.05). (4)Negative geotaxis test: the time for rats to turn 180°upward in RS group((7.67±1.36)s) was longer than that in the CONT group ((4.50±2.66)s) and RS+ MEL group ((6.17±0.75)s) (P<0.05). (5)Open field test: the time for rats to begin to run in the RS group ((8.17±3.86)s) was longer than that in the CONT group ((3.00±1.41)s) (P<0.05). Conclusion The neurobehaviors are damaged following flurothyl-induced recurrent neonatal seizures, and melatonin can reduce the neurobehavioral injury. Key words: Neonatal; Seizure; Melatonin; Neurobehavior