Microglial displacement of GABAergic synapses has endogenous protective function in generation of complex febrile seizures

摘要

OBJECTIVE Microglia-mediated dis-placement of synapses has been reported in the setting of experimental neuroinflammation,but its role in neurological disorders is poorly understood.Complex febrile seizures(FS) are the most common infantile seizures,yet its pathological progress is largely unknown.METHODS Mice pups(postnatal 8-10 d) were posted to 43℃ hyperthermia condition to develop FS,and then the latency and threshold of seizures were determined.The displacement of synapses was observed through immunofluorescence staining.We researched whether microglial displacement of GABAergic synapses will influence complex FS-induced increase in GABAergic neurotransmission and neuronal excitability with patch-clamp electrophysiology.Moreover,we used the CD11 bD TR mice to selective ablation of microglia or pharmacological inhibition of microglia to observe their effects on susceptibility to FS and synaptic stripping.RESULTS GABAergic presynaptic terminals surrounding neuronal soma and GABAergic transmissions were increased in complex FS.Meanwhile,the activated microglia ensheathe glutamatergic neuronal soma to displace,but do not phagocytize,GABAergic presynaptic terminals.Patch-clamp electrophysiology established that the microglial displacement of GABAergic synapses reduced complex FS-induced increase in GABAergic neurotransmission and neuronal excitability,while GABA exerts excitatory action in this immature stage.Moreover,pharmacological inhibition of microglial displacement of GABAergic synapses or selective ablation of microglia in CD11 bDTR mice promoted the generation of complex FS.CONCLUSION Displacement of GABAergic synapses by microglia is a protective event in the pathological progress of complex FS.