Blood pressure rhythm and circadian clock protein expression after cerebral ischemia-reperfusion in spontaneously hypertensive rats / 国际脑血管病杂志

ABSTRACT

Objective:To investigate the changes of blood pressure and serum circadian clock protein levels after cerebral ischemia-reperfusion in spontaneously hypertensive rat (SHR) and their correlation.Methods:The middle cerebral artery occlusion method was used to prepare the SHR cerebral ischemia-reperfusion model at zero point of Zeitgeber Time (ZT), and the systolic blood pressure within 24 h was continuously monitored after the model was made. The tail vein blood of rats was taken every 3 h, and the changes in serum circadian clock proteins (CLOCK, BMAL1, PER1 and CRY1) levels were detected by enzyme-linked immunosorbent assay. Pearson correlation analysis was used to determine the relationship between blood pressure circadian rhythm pattern and circadian clock protein level fluctuation after cerebral ischemia-reperfusion.Results:In the sham operation group, there were various blood pressure patterns, including dipper (53%), non-dipper (27%), super dipper (13%), and reverse dipper (7%), and the main pattern was dipper. In contrast, the degree of blood pressure disorder in the model group was aggravated, and the non-dipper was the main type, with the proportion as high as 40%. The proportion of super dipper and reverse dipper increased to 27% and 13% respectively; proportion of dipper blood pressure decreased to 20%. The serum level of CLOCK in the model group was relatively stable, while the circadian rhythm of BMAL1, PER1 and CRY1 was significantly changed compared with the sham operation group. Pearson analysis showed that PER1 was negatively correlated with the dipper ( r=-0.565, P=0.002) and super dipper ( r=-0.531, P=0.001) blood pressure patterns, and positively correlated with the non-dipper blood pressure pattern ( r=0.620, P<0.001). Conclusion:The circadian rhythm pattern of blood pressure in SHR after cerebral ischemia-reperfusion was obviously disordered, which was closely associated with the regulation of Per1 gene.