Altered Expression of c-Jun, Bcl-2 and Bax, and Apoptotic Cell Death in Rat Hippocampus Following Kainic Acid-Induced Seizures

Yi, Sang Won; Kim, Kwang Soo; Kim, Min Jeong; Kim, Jong Kuk; Yoo, Bong Goo; Ahn, Ji Hyun; Chang, Hee Kyung

Abstract

PURPOSE: To investigate whether c-Jun, Bcl-2 and Bax expressions are altered in rat hippocampus after kainic acid (KA)-induced seizures, and to determine whether such changes correlate with apoptotic cell death.
METHODS
Forty male Sprague-Dawley rats were used. Thirty rats were assigned to the experiment group, and 10 rats the control. KA (20 mg/kg) was injected once intraabdominally. The behavioral patterns were observed after the injection. The rats' brain was extracted 4, 24, and 72 hours after KA injection. c-Jun, Bcl-2 and Bax expression were evaluated by immunohistochemistry, and apoptosis by TUNEL staining. The expression of c-Jun, Bcl-2 and Bax at each hippocampal region were compared, and the relationship between c-Jun, Bcl-2 and Bax expression, and apoptosis was investigated.
RESULTS
c-Jun expression was increased at CA1, CA3 and CA4 regions 4 hours after the injection, and the increased expression was continued to 72 hours at CA3 region. Bcl-2 expression was increased at CA1, CA3 and CA4 regions 4 and 24 hours after the injection, and the increased expression was continued to 72 hours at CA3 region. Bax expression was increased at CA3 and CA4 regions 4 hours after KA injection, and the increased expression was continued to 72 hours at CA3 region. Apoptosis was significantly increased at CA3 region 4 hours after KA injection.
CONCLUSION
c-Jun expression was increased in hippocampus after KA-induced seizures, and cell death-regulating proteins Bcl-2 and Bax expression, and apoptosis were increased at similar regions. These results suggest that c-Jun might be activated in KA-induced apoptotic cell death mechanism.