Effects of Tadalafil on the Cerebral Ischemia-induced Apoptotic Neuronal Cell Death in Motor Cortex of Gerbils

Ko, Il Gyu; Kim, Sung Eun; Kim, Dong Hyun; Kim, Tae Woon; Kim, Bo Kyun; Shin, Mal Soon; Kim, Chang Ju; Na, Yong Gil; Joo, Kwan Joong; Kim, Khae Hawn

Abstract

PURPOSE
Cerebral ischemia leads to neuronal cell death, and eventually causes neurological impairments. Tadalafil is a long-acting phosphodiesterase type-5 (PDE-5) inhibitor, and it has been used for the treatment of erectile dysfunction. In the present study, we investigated whether tadalafil has the protective effect on apoptotic neuronal cell death in the motor cortex following transient global ischemia in gerbils.
MATERIALS AND METHODS
For this study, Mongolian gerbils were used for the experimental animals, and transient global ischemia was induced to the gerbils by occlusion of both common carotid arteries for 7 min. Gerbils were randomly divided into five groups (n=8 in each group): the sham-operation group, the cerebral ischemia-induced group, the cerebral ischemia-induced and 0.1 mg/kg tadalafil-treated group, the cerebral ischemia-induced and 1 mg/kg tadalafil-treated group, the cerebral ischemia-induced and 10 mg/kg tadalafil-treated group. Tadalafil-treated groups received tadalafil orally once a day for a 7 consecutive days, starting one day after surgery. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and immunohistochemistry for caspase-3 were performed for the detection of apoptotic neuronal cell death in the motor cortex.
RESULTS
The number of TUNEL-positive cells was 21.45+/-3.69/section in the sham-operation group, 771.66+/-97.25/section in the cerebral ischemia-induced group, 688.44+/-81.35/section in the cerebral ischemia-induced and 0.1 mg/kg tadalafil-treated group, 295.66+/-36.34/section in the cerebral ischemia-induced and 1 mg/kg tadalafil-treated group, and 198.47+/-25.25/section in the cerebral ischemia-induced and 10 mg/kg tadalafil-treated group. In the present results, induction of ischemic injury increased apoptotic neuronal cell death in the motor cortex of gerbils. However, tadalafil treatment suppressed the cerebral ischemia-induced apoptotic neuronal cell death in the motor cortex as dose-dependently.
CONCLUSIONS
Here in this study, we showed that tadalafil has protective effect on the cerebral ischemia-induced apoptotic neuronal cell death, and thus this drug may facilitate the recovery following ischemic cerebral injury.