What role sex hormones play in the hippocampus of Amazon rodent submitted to lithium-pilocarpine?

Resumen

Sex hormones and epilepsy relation is complex, so far not completely understood. Proechimys guyannensis, an Amazonian rodent commonly described as an animal model of resistance to epileptogenesis, still captive us with their natural endogenous mechanism. The aim of this study was to determine the relationship between sex hormones receptors with GABA interneurons and metabotropic glutamate receptor 2/3 in the hippocampus of Proechimys females submitted to the lithium-pilocarpine epilepsy model. Thirty-six Proechimys females, ovariectomized and non-ovariectomized were treated with repeated administration of pilocarpine. After 30- and 90-min post Status Epilepticus (SE), animals were decapitated. Using Western blotting we analyzed the expression of ER-beta, ER-alpha, progesterone,mGlu2/3, and GABA antibodies in hippocampus. Data was analyzed with two-way ANOVA test. Subsequently, we used immunofluorescence to colocalized ER-alpha and beta, and progesterone with GABA and mGlu2/3 in the hippocampus regions. Images were captured with confocal microscopy and analysis was done with Image J software. High levels of ER-alpha protein expression were detected. Group and ovariectomy affected ER-alpha expression. Although, ER-beta and mGlu2/3 receptor showed no effect in the expression. Group affected progesterone expression, and ovariectomy GABA. Immunofluorescence showed also a higher presence of ER-alpha rather than beta. CA2, CA3, and hilus were the principal regions with changes in colocalization throughout groups and antibodies combination. High levels of ER-alpha protein expression may suggest some protective effect since ER-alpha has shown a critical role in estrogen-induced protection against brain injury. Predict whether the expression of beta and alpha ER lead to seizure resistance or if seizure events lead to beta and alpha expression changes is difficult. Progesterone a powerful anticonvulsant, colocalized principally with mGlu2/3 in CA3 region. These facts might lead to analyze how sex hormones interact in the Proechimys hippocampus and might be the clue of the epileptogenesis resistance.