Effect of Combination Therapy Using Hypothermia and Granulocyte Colony-Stimulating Factor in a Rat Transient Middle Cerebral Artery Occlusion Model

Stroke is the third leading cause of death. Hypothermia has been recognized as an effective method in reducing brain injury. In this study, we assessed the effects of granulocyte colony-stimulating factor (G-CSF) as a neuroprotective agent and mild hypothermia on mortality, behavioral function, infarct volume, and brain edema in Wistar rats. Forty male rats were used in five groups (eight rats in each group): control, hypothermy, G-CSF, combination hypothermy + CSF, and sham. Rats were anesthetized by injection of chloral hydrate (400 mg/kg) intraperitoneally. Transient cerebral ischemia was induced by 60-min intraluminal occlusion of left middle cerebral artery. Hypothermia, initiated at the time of reperfu‌sion and G-CSF was started one hour after reperfusion at a dose of 15 mg/kg subcutaneously. The motor behavior was measured using Garcia’s index and animals were assigned for the assessments of infarction, brain swelling, and mortality rate. The mortality was 38.46% (control group) and reduced in other groups. Neurological deficit score of control group (40.31 ± 1.56) was significantly lower than in treatment groups. The total cerebral infarct volume of treatment group was significantly lower than control group (43.96 ± 44.05 mm3). Treatment with hypothermy plus G-CSF (2.69 ± 0.24%) could significantly reduce brain swelling volume than other treatment groups. Our major finding is that mild hypothermic treatment plus G-CSF significantly reduced mortality rate and edema and improved neurological function. The results suggest that the combination of hypothermia and G-CSF is more effectively than other treatment groups being used alone.