Avaliação da expressão de mRNA de mdr1, TNF-alfa, ATP6 ap2 beta-actina em rato wistar audiogênico

Abstract

Epilepsy is a disorder caused by focal or generalized paroxysmal discharges in the brain reflecting in its function. The quadrigeminal plate is directly related to hearing pathway and when electrically stimulated, may cause similar seizures in normal animals as visualized in audiogenic rats. This study used the Wistar Audiogenic Rats (WAR) as an experimental model of epilepsy to analyze mdr1, TNF-, ATP6ap2 and -ctina genes expression. Those animals present severity index (SI) related to seizures caused by sound stimuli from SI0.23 (resistant) to SI0.85 (sensitive). To evaluate gene expression of mdr1 and TNF- were analyzed right and left cortices, hippocampi and quadrigeminal plate. A second group of animals received siRNA and its quadrigeminal plates were removed for analysis. The seizure severity was analyzed by SI score. Total RNA was extracted by Trizol® and submitted to real time RT-PCR analyze. Data showed that five days after the third stimulus group had higher expression of TNF- (4.69±1.0) and mdr1 (3.84±0.7) mRNA at the quadrigeminal plate of WAR with SI0.85 compared to TNF- (1.44±0.4) and mdr1 (1.25±0.4) mRNA of WAR SI0.23. In the 25 days after third stimulus group, the same genes were down-regulated (0.52±0.1) and (0.61±0.1), respectively, in WAR with SI0.85. No other tissue showed difference in the expression of these genes. ATP6ap2 mRNA was down regulated (0.52±0.04) in the first group and upregulated in the second group compared to WAR SI0.23 (1.01±0.1). -actin mRNA had no significant difference in any subgroups. The higher TNF- and mdr1 mRNA and lower ATP6ap2 mRNA expression in quadrigeminal plate show that these genes are involved at the functional mechanism of epilepsy in WAR model. Tissue analysis showed that quadrigeminal plate is the main region for the genetic differences observed among WARs, since it is related to the hearing pathway. Many pathways and cellular mechanisms at quadrigeminal plate linked to epilepsy in rats SI0.85 are unknown and need to be understood.