Objective: To investigate the role of neuropeptide Y(NPY) positive interneurons in the generation and compensation of temporal lobe epilepsy.
Methods: Pilocarpine-induced rat model was founded. Immunohistochemistry was used to observe the number changes and axonal sprouting of NPY interneurons at different time points in the hippocampus of rats.
Results: After lithium-chloride and pilocarpine administration, 92.9% rats were induced status epilepticus (SE) successfully, and the mortality rate was 19.2%. In the experimental group, the number of NPY positive neurons decreased in the hilus of the hippocampus, and was least on 7 d after the SE (P<0.01). In the chronic phase, the number of hilus NPY neurons partially recovered, but was still less than the number in the control group on 60 d after the SE (P<0.05). No evident changes of the number of NPY neurons existed in CA domains (P>0.05) except the loss of them in CA3 area on 7 d after the SE (P>0.05). Increased NPY positive fibers could be seen in the molecular layer of the dentate gyrus on 30 d after the SE.
Conclusion: NPY interneurons have different sensitivities to the injuries induced by seizures at different time points and domains. Loss of NPY interneurons plays an important role in the generation of temporal lobe epilepsy, while axonal sprouting of them may play a significant role in the compensation of temporal lobe epilepsy.