[Susceptibility to seizures and expression of fibroblast growth factor 17 in rats with Cortical dysplasia and its effects on the hippocampal neurons].

OBJECTIVE

To assess the susceptibility to seizures, expression of fibroblast growth factor 17 (Fgf17) in rats with Cortical dysplasia (CD), and its effect on hippocampal neurons.

METHODS

Pregnant SPF SD rats were intraperitoneally injected with Carmustine on E17 to establish a model of CD in the offspring rats. The offspring were randomly divided into the normal control, epilepsy group, CD group, and CD plus epilepsy group (n = 20 each). At 6 weeks of age, the rats from the epilepsy and CD plus epilepsy group were intraperitoneally injected with lithium chloride and pilocarpine to induce status epilepticus (SE). Quantitative real-time PCR and Western blotting were used to detect the mRNA and protein levels of Fgf17 at 24 hours and 30 days post-SE, respectively. An electrophysiological signal system was used to record the firing rate, amplitude, and seizure duration of the electroencephalogram (EEG) in rats from the 4 groups at 30 days post-SE. According to the concentration of Fgf17 in the culture medium, 12 1-day-old rats were divided into the control group, 500 nmol/L Fgf17 group, and 1 000 nmol/L Fgf17 group (n = 4 each). Immunofluorescence staining was used to observe the morphometry and number of hippocampal neurons in the 3 groups. This study was approved by the Ethics Committee of the Fifth Affiliated Hospital of Zhengzhou University (Ethics No.: KY2023005).

RESULTS

Hematoxylin-Eosin (HE) staining indicated CD in rats from the CD group and CD plus epilepsy group. Compared with the epilepsy group, the CD plus epilepsy group exhibited a faster rate of seizure onset, higher EEG amplitudes, and longer seizure at 30 days post-SE (P < 0.05). Both the CD and the CD plus epilepsy groups showed lower mRNA and protein expressions of Fgf17 in the hippocampus at 24 hours and 30 days post-SE compared with the control and epilepsy groups (P < 0.05), with the expression significantly decreased in the CD plus epilepsy group. Both the 500 nmol/L and the 1 000 nmol/L Fgf17 groups showed a greater number of hippocampal neurons compared with the control group (P < 0.05). The number of hippocampal neurons in the 1 000 nmol/L Fgf17 group was significantly greater compared with the 500 nmol/L Fgf17 group (P < 0.05).

CONCLUSION

Rats with CD exhibit decreased Fgf17 expression and increased epileptogenic susceptibility, which may be associated with reduced number of hippocampal neurons.