Influence of edaravone on microcirculation in injuried area of cerebral injury SD rats by optical intrinsic signal imaging (OISI) observation

Abstract

Objective To monitor the changes of microcirculation after free radical scavenger edaravone treatment by optical intrinsic signal imaging (OISI) in injuried area of cerebral injury SD rats in vivo. Methods Sixty male SD rats were randomly divided into 3 groups: normal group (n=20) , control group ( injury group, n=20) and experimental group (free radical scavenger edaravone- treating group, n= 20). A steel needle was penetrated into cerebral somatosensory area in rats to establish cerebral injury animal models. The rats in experimental group were intraperitoneal injected with free radical scavenger edaravone (3 mg/kg) after cerebral injury. Only operation without administration was performed in control group and the rats in normal group did not receive any treatment. Change character of optical intrinsic signals were recorded in the exposed cortex of all the rats with light illumination using (546±10) nm and (605±10) nm wavelength. Results All the rat models in control group and experimental group were successfully established. Effective dada were acquired from 20 rats in normal group, 12 rats in control group [6 rats in(546±10) nm wavelength and 6 rats in (605±10) nm wavelength] , and 8 rats in experimental group [3 rats in (546±10) nm wavelength and 5 rats in (605±10) nm wavelength] in OISI experiment. The gray scale change curve of reflected light intensity in normal group was fairly gentle. The curve of control group had lots of wave crests. The curve of experimental group had g stages. There was a wave crest in P1 stage and its amplitude was (5.7± 3.5)% of baseline. P1 stage lasted for 2.5 minutes. Reflected light intensity increased with time in P2 stage and lasted for 1 hour. Reflected light intensity decreased with time in P3 stage and lasted for 40 minutes. The amplitudes of five wave crests in P4 stage were (7.1±3.2)%, (8.3±1.8)%, (10.7±1.5)%, (9.9±1.6)% and (7.4±2.0)% of baseline respectively. The durations of wave crests in P4 stage were 1.5, 2.5, 4.4, 4.2 minutes and 4 minutes respectively. There were significant differences of gray scale of reflected light intensity among three groups (F=6.050, P<0.05). Furthermore, after hindlimbs of rats were stimulated, the function response persistence time of somatosensory area was 7 to 8 s in normal group and 11 to 15 s in control group. After intraperitoneal injection of edaravone, the function response course of somatosensory area was the same with the rats in normal group on the whole, but persistence time reduced and was 5 to 5.5 s in experimental group. Conclusions Free radical scavenger edaravone has relatively strong protection effect on blood-supply regulation in brain tissue of injuried area and can obviously improve blood circulation in somatosensory area of cerebral injury. Edaravone can keep relatively stable situation of cerebral microcirculation in the injured areas of cerebral injury rats to some extent. Key words: Brain injuries; Free radical scavengers; Microcirculation; Optical imaging; Edaravone