Role Of JAK2/STAT3Signal Channels In Mediating Granulocyte Colony-stimulating Factor Effect On Apoptosis Following Cerebral Hemorrhage In Rats

Objective: Cerebral hemorrhage, frequently occurring clinical,higher fatality rate, is common disease, unknown pathogenesis and lackof effective treatment. So clarifying pathogenesis and looking for moleculartarget therapy is particularly important. To study the effect of granulocytecolony stimulating factor (G-CSF) on neuronal apoptosis following cerebralhemorrhage (ICH) and the role of JAK2/STAT3signal pathway in theprocess. Methods:120healthy adult SD rats, irrespective of gender, weighingbetween250and300g, aged2~3months, were divided into controlgroup, intracerebral hemorrhage group and treatment group. According to thedifferent time, each group is divided into five groups, including6h,24h,48h,72hand168h group.In intracerebral hemorrhage Group, using the method ofmodified two times injection of50μL autologous arterial blood that is notsolidified, established cerebral hemorrhage model in rats.In control group,autologous arterial blood was instead of50μL saline. Treatment group wereinjected G-CSF60μg/kg intraperitoneally after surgery an hour at each timepoint, which were injected once at6h group, twice at24h group, three times at48h group, four times at72h group, five times at168h group and the injectioninterval were12h.After the success of modeling, the rats at each time pointwere collected for neurological dysfunction score.Then, with1%sodium pentobarbital intraperitoneal injection anesthesia, brains were removed rapidlyand saved in4%neutral Formaldehyde Solution, for paraffin embedding,slicing, staining for HE, P-JAK2, P-STAT3for immunohistochemistry andapoptosis for TUNEL. Results:(1)The neurological dysfunction score oftreatment group compared with control group at each time point, score islower(P<0.05) and neural function defect. The neurological dysfunction scoreof treatment group compared with cerebral hemorrhage group at each timepoint, score is higher(P<0.05) and neural function lighter.Nerve function isdamaged seriously at48h (P<0.05) in cerebral hemorrhage group and treatmentgroup.(2)In control group, structure of brain tissue was complete, nucleus,cytoplasm uniform. In intracerebral hemorrhage group, nerve cells around thehematoma edema were visible and found a large number of blood cells,inflammatory cells and swelling of nerve cells at6h and24h.Then therenecrosis, nuclear condensation, nuclear dissolution, dyeing were visible andblood cells and inflammatory cell were decreased, a small amount of glial cellproliferation at48h and72h. Nerve cells and inflammatory cells obviouslydecreased and glial cells increased at168h.In treatment group, the expressionwas similar to in intracerebral hemorrhage group at6h and24h. The swellingrange of nerve cell necrosis were less than intracerebral hemorrhage group andstill visible inflammation cell infiltration and proliferation of glial cells at48h,72h and168h.(3)In intracerebral hemorrhage group and treatment group, therewere visible a few neuronal apoptosis at6h, significantly increased at24h and 48h, reached the peak at72h (P <0.05) and still had the expression at168h.Each sub group compared with the control group, the expression increased (P <0.05). The treatment group compared with intracerebral hemorrhage group, theexpression decreased (P <0.05) at each time point.(4)In intracerebralhemorrhage group and treatment group, the positive cells of P-JAK2andP-STAT3were a small amount of expression at6h, obviously increased at24h,and reached the peak at48h (P <0.05), beginingly decreased at72h and stillhad the expression at168h. Compared with control group, the positive cellsincreased (P<0.05) and treatment group compared with intracerebralhemorrhage group, the expression decreased (P <0.05).(5)In intracerebralhemorrhage group, neulogical dysfunction score was negatively correlated withthe expression of neuronal apoptosis P-JAK2and P-STAT3respectively(r=-0.637，r=-0.848, r=-0.848, P<0.05), the neuronal apoptosis was positivelycorrelated with the expression of P-JAK2and P-STAT3(r=0.466, r=0.760,P<0.05). Conclusion: Granulocyte colony-stimulating factor can obviouslyreduce neurological impairment following cerebral hemorrhage and decreasethe expression of neuronal apoptosis and P-JAK2, P-STAT3protein to protectnerve function in rats. In the process, JAK2/STAT3signaling pathway maymediate G-CSF on neuronal apoptosis following intracerebral hemorrhage inrats.