Effect of Diazepam on the Expression of Transforming Growth Factor-Beta in Rat Brain Following Transient Cerebral Ischemia

Shin, Jong Hwan; Kim, Jin Joo; Jung, Tae Gyo; Yang, Hyuk Jun; Kim, Jae Kwang; Lee, Gun; Park, Cheol Wan; Hwang, Sung Youn

Abstract

OBJECT: Transforming growth factor-beta (TGF-beta) is involved in many physiological and pathophysiological processes, such as cell growth, differentiation, inflammation, and tissue repair. It is not yet clear whether the presence of this cytokine has deleterious or protective effects for neurons in a given pathophysiological condition. Several authors have demonstrated that TGF-beta has been shown to rescue cultured neurons from excitotoxic and hypoxic cell death and to reduce infarct size after focal cerebral ischemia in mice and rabbits. The present study investigated the effect of diazepam on the expression of TGF-beta in rat brain tissue after inducing transient cerebral ischemia.
METHODS
Ten male rats were killed after a mild and reversible ischemic damage produced by a 15-minutes occlusion of both carotid arteries without occlusion of the vertebral arteries. Five ischemia-treated and 5 sham-operated rats were injected with 10 mg/kg diazepam and vehicle, respectively at 30 minutes, and again 90 minutes following the onset of reperfusion. After 1, 2 and 7 days following the reperfusion, brains were removed from control, sham-operated, and ischemia-treated with or without diazepam-injected groups, then immunohistochemistry and Western blotting for TGF-beta were performed. Cerebral cortices and hippocampi were sectioned from ischemia-treated, shamoperated and control group rats, and stained using cresyl violet.
RESULTS
When the immunoblot-results of TGF-beta expression were analyzed using a image analysis system, TGF-beta expression were increased in ischemia-treated without diazepam-injected rats, and decreased in ischemia-treated with diazepam-injected rats at 2 and 7 days after reperfusion compared to control and sham-operated groups. Cresyl violet staining became intense in ischemia-treated without diazepam-injected group and became unclear in ischemia-treated with diazepam-injected group compared to sham-operated and control groups, respectively.
CONCLUSION
Diazepam influenced the TGF-beta expression in the brain of ischemia-treated rats.