PK-PD Correlation of Erigeron Breviscapus Injection in the Treatment of Cerebral Ischemia-Reperfusion Injury Model Rats

By measuring the cerebral infarction rate and neurological behavioral score of rats in a sham operation group, an MCAO model control group and an Erigeron breviscapus injection treatment group, we explored the therapeutic effects of Erigeron breviscapus injection on brain tissue and neuroethological injury in rats. Plasma samples were collected at 18 time points after intravenous injection of Erigeron breviscapus. The levels of scutellarin, 4-caffeoylquinic acid, 5-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid, chlorogenic acid and isochlorogenic acid B in rat plasma at the various time points were determined by an HPLC method, and drug concentration versus time plots were constructed to estimate the pharmacokinetic parameters. Finally, a PK-PD combined model was used to analyze the relationship between the blood concentration, time and therapeutic effects of the seven active components. The results of the pharmacodynamics studies showed that the cerebral infarction rate of rats in the Erigeron breviscapus injection group decreased significantly at 5 min, 10 min, 20 min, 6 h, 8 h, 18 h, 24 h, 32 h, 40 h and 48 h after cerebral ischemia. Abnormal neurological behavior scores were significantly reduced after 4 h of cerebral ischemia. The pharmacokinetics results showed that the seven chemical constituents in Erigeron breviscapus injection reached their highest detection value after 5 min of cerebral ischemia. The lowest detection values of scutellarin and isochlorogenic acid B appeared after 6 h of cerebral ischemia but could not be detected after 8 h. The lowest detection values of 5-caffeoylquinic acid and 4,5-dicaffeoylquinic acid were found in the third hour of cerebral ischemia but not after 4 h. The lowest detection values of 4-caffeoylquinic acid, 3,5-dicaffeoylquinic acid and chlorogenic acid were found during the second hour of cerebral ischemia but not at the third hour. However, at 18 h, 24 h, 32 h and 40 h of cerebral ischemia, the cerebral infarction rates of rats in the Erigeron breviscapus injection group were significantly reduced, with decreased values of 6.22%, 11.71%, 6.92% and 4.96%, respectively, and the effects were stronger than those after 5–20 min of cerebral ischemia. The decreased values reached their highest value after 24 h of cerebral ischemia. Our results show that the effects of Erigeron breviscapus injection on reducing the cerebral infarct rate in MCAO model rats are characterized by a fast onset and long maintenance time. The 5-min blood concentration in cerebral ischemia was the highest test value, and after this time, the cerebral infarction rate of MCAO rats began to decrease. However, the peak value of the effects lagged behind that of the plasma concentration. The maximum effective time for Erigeron breviscapus injection appeared 24 h after cerebral ischemia, which provides a reference for the screening of specific drugs for ischemic stroke, optimal dosing regimens and rational clinical drug use.