The effect of head-down tilt in experimental acute ischemic stroke

Background Collateral therapeutics exert a promising protective effect on the outcome of acute ischemic stroke. Cerebral blood flow (CBF) may be modulated by different head positioning. The current study aimed to determine the effect of head-down tilt (HDT) on stroke in a rodent model. Methods The model of middle cerebral artery occlusion and reperfusion (MCAO/R) was used in this study. Neurological deficit scoring, 2,3,5-triphenyltetrazolium chloride staining, brain water content, perivascular aquaporin protein-4 (AQP4) localization, pericyte marker platelet-derived growth factor receptor beta (PDGFR beta), and CBF velocity were evaluated at 24 h after MCAO/R and HDT treatment. Results In the rat model of MCAO/R, brain infarct volume and neurological deficit score were significantly alleviated in the -30 degrees and -60 degrees groups compared to those in the lying flat (0 degrees) group. Compared with the 0 degrees group, an increase in CBF velocity was detected in the -30 degrees group through two-photon microscopy imaging at 24 h after MCAO/R. Compared with the SHAM group, a decrease in PDGFR beta was observed in both the MCAO/R and HDT treatment (-30 degrees) groups. The integrated optical density of PDGFR beta was found to be higher in the HDT treatment (-30 degrees) group than in the MCAO/R group. An impairment in perivascular AQP4 polarity and an increase in brain water content were observed after MCAO/R, which were not exacerbated by HDT treatment (-30 degrees). Conclusions Our findings suggest that HDT treatment at certain degrees may exert a neuroprotective effect after MCAO/R through improving CBF velocity and the protection of pericytes.

Automated summary

The study suggests that head-down tilt treatment at certain degrees may provide neuroprotective effects after MCAO/R by improving cerebral blood flow velocity and protecting pericytes.