OBJECTIVETo investigate the changes in the expression of EphA5 and its ligand ephrinA5 in the hippocampus of rats with epilepsy and their role in the pathogenesis of temporal lobe epilepsy (TLE).

METHODSA total of 240 Sprague-Dawley rats were randomly divided into control group and TLE group, with 120 rats in each group. A rat model of lithium-pilocarpine TLE was established, and then the rats were divided into subgroups at 12 and 24 hours and 7, 15, 30, and 60 days after epilepsy was induced. In-situ hybridization was used to measure the mRNA expression of ephrinA5 in the CA3 region and the dentate gyrus of the hippocampus in 9 rats; immunohistochemistry was used to measure the protein expression of EphA5 in the CA3 region and the dentate gyrus of the hippocampus in 9 rats; Neo-Timm silver staining was used to observe mossy fiber sprouting in the CA3 region of the hippocampus in 2 rats.

RESULTSIn-situ hybridization showed mRNA expression of ephrinA5 in the CA3 region of the hippocampus, but this was not found in the dentate gyrus. Compared with the control group at the same time point, the TLE group had a significant reduction in the mRNA expression of ephrinA5 in the CA3 region of the hippocampus at 7 and 15 days after epilepsy was induced (P<0.05); at 30 and 60 days after epilepsy was induced, the TLE group had a gradual increase in the mRNA expression of ephrinA5 in the CA3 region of the hippocampus, and there was no significant difference between the TLE and control groups (P>0.05). Immunohistochemistry showed that EphA5 protein was expressed in the CA3 region and the dentate gyrus of the hippocampus and had a similar trend of change as ephrinA5 mRNA. Neo-Timm silver staining showed that the TLE group developed marked mossy fiber sprouting in the CA3 region of the hippocampus at 7 and 15 days after epilepsy was induced.

CONCLUSIONSDownregulation of ephrinA5 and EphA5 in the CA3 region of the hippocampus may participate in the mechanism of mossy fiber sprouting and is closely associated with the development and progression of epilepsy.

Animals ; Ephrin-A5 ; analysis ; genetics ; physiology ; Epilepsy, Temporal Lobe ; etiology ; metabolism ; Hippocampus ; chemistry ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptor, EphA5 ; analysis ; genetics ; physiology

OBJECTIVESTo study the expression patterns of two Eph family molecules, the receptor EphA5, and the ligand ephrin-A5, during spinal cord development.

METHODSThe receptor expression was analyzed using beta-galactosidase knockin mice, and affinity ligand probe binding. The ligand expression was assessed using two different affinity probes, and knockout mouse tissues as controls.

RESULTSEphA5 was expressed in the ventral spinal cord, while ephrin-A5 was located in the dorsolateral regions of the spinal cord throughout development.

CONCLUSIONSThese results show that EphA5 and ephrin-A5 are expressed over broad developmental stages and may play important roles in establishing the dorsoventral organization of the spinal cord.

Animals ; Ephrin-A5 ; biosynthesis ; Gene Expression ; Gene Expression Regulation, Developmental ; Immunohistochemistry ; Mice ; Mice, Inbred C57BL ; Mice, Mutant Strains ; Receptor, EphA5 ; biosynthesis ; Spinal Cord ; embryology ; metabolism

OBJECTIVE: To investigate the relationship among mossy fiber axon sprouting(MFS), synaptic reorganization, and the alteration of expression of Eph A5 and ephrin A3 in the dentate gyrus in rats with pilocarpine-induced chronic temporal lobe epilepsy. METHODS: Mossy fiber sprouting and synaptic formation in rats were observed by Neo-Timm staining, after the acute status epilepticus and chronic spontaneous temporal lobe epilepsy induced by lithium-chloride and pilocarpine. In situ hybridization was used to detect ephrin A3 mRNA and an immunohistochemical staining was applied to determine Eph A5 protein. RESULTS: In entorhinal cortex, only Eph A5 mRNA and protein expressed, which significantly decreased on Day 7 after pilocarpine induced status epilepticus(P<0.01),and resumed to normal levels on Day 30 (P>0.05). In the dentate granule cells, ephrin A3 mRNA reduced obviously on Day 7 after pilocarpine-induced status epilepticus (P<0.01), and returned to normal levels on Day 30 (P>0.05). CONCLUSION The down-regulation of Eph A5 mRNA and protein in entorhinal cortex and dentate gyrus, and ephrin A3 mRNA in dentate gyrus after status epilepticus may be part of the endogenous molecular mechanism of mossy fiber sprouting to the inner molecular layer of dentate gyrus.
Animals ; Axons ; physiology ; Chromosome Pairing ; physiology ; Dentate Gyrus ; physiopathology ; Down-Regulation ; Ephrin-A3 ; biosynthesis ; Epilepsy, Temporal Lobe ; chemically induced ; metabolism ; physiopathology ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Receptor, EphA5 ; biosynthesis ; Status Epilepticus ; chemically induced ; metabolism ; physiopathology