One of the main non-psychoactive phytocannabinoids of cannabis is cannabidiol (CBD), which has attracted much attention for its neuroprotective roles. The present study was designed to assess whether pretreatment of CBD can attenuate two of the destructive processes of cerebral ischemia, including oxidative stress and cell death. The male rats were randomly divided into 6 main groups (control, MCAO, vehicle, and CBD-treated groups). Using stereotaxic surgery, a cannula was inserted into the right lateral ventricle of the rat brain. CBD was injected at doses of 50, 100 and 200 ng/rat for five consecutive days. After pretreatment, middle cerebral artery (MCA) was blocked for 60 min using the intraluminal filament technique. 24 h after reperfusion, each main group was considered for measurement of infarct volume, superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), p53 gene expression, pathological alterations, and expression of Bax, Bcl-2, cytochrome C, and caspase-3 proteins. The results revealed that CBD at dose of 100 ng/rat reduced the infarction volume and MDA level in cortical and striatal areas of rat brain compared with vehicle group. In addition, the CBD at dose of 100 ng/rat elevated the activity of SOD enzyme in cortex and striatum. The increase in the activity of CAT was also seen at dose of 100 ng/rat in cortex. Furthermore, the Bcl-2/Bax ratio was significantly diminished by the dose of 100 ng/rat CBD in cortex. Moreover, a decrease in expression of cytosolic cytochrome C was observed by CBD at doses of 100 and 200 ng/rat in cortex. CBD at doses 100 and 200 ng/rat also reduced the expression of caspase-3 in cortical and striatal areas, respectively. P53 was downregulated following administration of CBD at dose of 100 ng/rat. Moreover, histological analysis showed the decrease in the percentage of pyknotic neurons in 100 and 200 ng/rat CBD-received groups. CBD played the anti-apoptosis and anti-oxidant roles in cerebral ischemia by affecting the pathways of intrinsic apoptosis, endogenous antioxidant enzymes, and lipid peroxidation.
Keywords: Antioxidant enzymes; Bax/Bcl-2; Cannabidiol; Caspase-3; Cerebral ischemia; Cytochrome C; p53.
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