| Part One: Effects of topiramate on hippocampal neurons damage in immature rats with chronic seizure[Objective]To explore the effects of topiramate (TPM) on hippocampal neurons damage in immature rat with chronic seizure.[Methods]Sixty male Wistar rats aged 3 weeks were randomly divided into 5 groups. The rats in 4 of the groups (group B, C, D and E) were injected intraabdominally with Pentylenetetrazol (PTZ) to construct a murine model of epilepsy and then assigned to receive gastric infusion with either distilled water (group B) or TPM at a dose of 20 mg/kg, 40 mg/kg, or TPM 80 mg/kg (groups C, D and E) daily for 2 consecutive months. The rats in the remaining group received intraabdominal injection of normal saline and then gastric administration of distilled water (group A). Changes of body weight and behaviors of the rats were recorded. Levels of serum neuron-specific enolase(NSE) were measured by ELISA and the pathological changes in hippocampus were observed.[Results]1.Effect on body weightThere is no significant difference in group A and group B. TPM had influence on body weight gain of rats at this experimental condition. Body weight gain of rats in group C, D, E were lower than that of rats in group A, B ( P all < 0.001 ),and rats in group E were affected more significantly than ones in group C, D (P both < 0.001 ), while there is no significant difference in group C and group D.2. Effect on behaviors of the ratsNo seizure developed in group A. In group B, the frequency of seizure was (48.4±3.7)times, while in group C (44.7±2.9) times, in group D (44.3±3.1) times and in group E (42.7±3.2) times.Compared with group B, the frequency of seizure were significantly decreased in group C , D and E (P < 0.05 or P < 0.01 ).While there were no significant difference in group C, D, E.3. Effect on the levels of NSE in serumThe levels of NSE in serum were (18.717±2.954)μg/L,(35.713±5.974)μg/L,(27.402±6.401 )μg/L,(24.791±6.221)μg/L and (21.473±6.875)μg/L in group A, B, C, D, E , respectively. Compared with group A, levels of NSE were significantly increased in group C and D (P both < 0.01 ), but levels of NSE did not change significantly in group E. Compared with group B, levels of NSE were significantly decreased in group C , D and E (P all < 0.05 ). While there were no significant difference in group C, D, E.4. Effect on hippocampus pathomorphologyFew neuronal deaths in hippocampus were observed in group A. The number of dead neurons was significantly lower in group C, D, E than in group B (P all < 0.001) with a reversed relation with the dosage of TPM. The percentage of neuron death was (5.8±1.9)%,(72.2±9.8)%,(43.9±7.1)%,(25.9±5.5)%,(10.5±4.2)% in CA3 region of hippocampus and (5.1±1.8) %,(65.6±8.1)%,(40.5±6.4)%,(23.1±5.2)%,(8.9±3.6)% in CA1 region of hippocampus in group A, B, C, D, E , respectively.[Conclusion]TPM plays a protective role in epilepsy-induced neuronal damage in a dose-dependent manner. Part Two: Effects of topiramate and folic acid on hippocampal neurons damage in immature rats with chronic seizure[Objective]To explore the effects of topiramate (TPM) and folic acid (FA) on hippocampal neurons damage in immature rat with chronic seizure.[Methods]Forty-eight 3-week-old male Wistar rats were randomly divided into 4 groups of 12 rats each. The rats in 3 of the groups (positive control group, TPM group, TPM + FA group) were injected intraabdominally with Pentylenetetrazol (PTZ) to construct a murine model of epilepsy and then assigned to receive gastric infusion with distilled water (positive control group), TPM 40 mg/ (kg. d) (TPM group), TPM 40 mg/ (kg. d) + FA 5 mg/ (kg. d) (TPM + FA group )daily for 2 consecutive months., respectively. The rats in the remaining group received intraabdominal injection of normal saline and then gastric administration of distilled water (negative control group). The seizure behaviors of the rats were recorded. Levels of serum neuron-specific enolase(NSE) were measured by ELISA and the pathological changes in hippocampus were observed.[Results]1. Effect on behaviors of the rats1.1 No seizure developed in the negative control group. Compared with the positive control group, frequencies of seizure occurred significantly fewer in TPM group and TPM + FA group (P both < 0.05). Frequencies of seizure were no significant difference between TPM group and TPM + FA group.1.2 Water maze test: The times of learning to swim to the platform rightly were (6.9±2.3) times,(9.3±2.6) times,(12.6±3.4)times,(8.4±2.7) times in negative control group,positive control group,TPM group and TPM + FA group, respectively. Compared with TPM group, the times were significantly decreased in negative control group,positive control group and TPM + FA group(P < 0.001 or <0.05)。2. Effect on the levels of NSE in serum The levels of NSE in serum were (18.717±2.954)μg/L,(35.713±5.974)μg/L,(24.791±6.221)μg/L and (22.550±7.019)μg/L in negative control group,positive control group,TPM group and TPM + FA group, respectively. Compared with the negative control group, levels of NSE were significantly increased in positive control group and TPM group ( P both < 0.01 ) , but levels of NSE did not change significantly in TPM + FA group. Compared with the positive control group, levels of NSE were significantly decreased in TPM group and TPM + FA group (P both < 0.05 ).3. Effect on hippocampus pathomorphologyLight microscope: Few neuronal deaths in hippocampus were observed in the negative control group. The number of dead neurons was significantly lower in TPM group and TPM + FA group than in the positive control group (P both < 0.01). The percentage of neuron death was (5.8±1.9)%,(72.2±9.8)%,(25.9±5.5)%,(16.1±4.8)% in CA3 region of hippocampus and (5.1±1.8)%,(65.6±8.1)%,(23.1±5.2)%,(14.9±4.3)% in CA1 region of hippocampus in negative control group,positive control group,TPM group and TPM + FA group, respectively.Electron microscopy: In the negative control group, ultrastructure showed the sharply demarcated boundary, clear nuclear membrane, clear inner and outer membrane and crista of in mitochondria in hippocampal neuron. Hippocampal neurons in positive control group,TPM group and TPM + FA group revealed marked ultrastructural changes, indicated by karyopyknosis, significant mitochondrial swelling, breakage and disappearance of mitochondria crista, vacuolar degeneration and disruption of the outer membrane of mitochondria. The damage degree of mitochondrial ultrastructure was (0.34±0.09),(3.76±0.28),(2.85±0.21)and (2.09±0.31)grade in negative control group,positive control group,TPM group and TPM + FA group, respectively, there were significant differences between four groups ( P < 0.01 ).[Conclusion]TPM has protective effect on hippocampal neurons damage in immature rats with chronic seizure , and FA can strengthen the neuroprotective role of TPM . |
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