Granulocyte Colony-Stimulating Factor Attenuates Blood-Brain Barrier Damage and Improves Cognitive Function in Spontaneously Hypertensive Rats

Background: Cerebral small vessel diseases (CSVDs) always coincide with endothelial dysfunction and blood-brain barrier (BBB) damage. However, the detailed mechanisms of CSVD are still unclear and the therapeutic efficacy is not so satisfaction. Granulocyte-colony stimulating factor (G-CSF) can play a neuroprotective role in many neurological diseases. We investigated whether G-CSF exerted positive effects on BBB protection and cognitive function improvement in spontaneously hypertensive rats (SHRs), a rat model displaying the early histopathological changes of CSVD. Method: Twenty-four-week-old SHRs received daily administrations of either G-CSF (50μg/kg) or normal saline (NS) for 7 days. The novel object recognition test (NORT) was then conducted after treatment. After behavioral test, we examined IgG fluorescence staining to indicate BBB leakage. G-CSF receptor (G-CSFR), aquaporin-4 (AQP4) and glial fibrillary acidic protein (GFAP) expression were determined by immunofluorescence. The surface structure of endothelial cells was examined by scanning electron microscopy (SEM). Results: G-CSF significantly attenuated IgG leakage and improved non-spatial memory in SHRs. G-CSFR was expressed at higher levels in both G-CSF-SHRs and NS-SHRs. The surface structural changed on the endothelial cells and expression of AQP-4 and GFAP decreased after G-CSF treatment. However, no significant differences in Claudin-5 expression were observed. Conclusion: These findings demonstrated that the administration of exogenous G-CSF can improve cognitive function in a model of CSVD, possibly due to the recovery of endothelial and BBB function.