Assessment of optical properties in cerebral ischemic rats by using near infrared spectroscopy

Ischemic stroke is a high prevailing disease and costly in industrialized countries. A valid animal model is essential to develop an extensive research. Among various models, we choose middle cerebral artery occlusion (MCAO) model as it is one of the common used ischemic stroke animal models. The purpose of our study is to investigate the optical properties of ischemic stroke by near infrared spectroscopy (NIRS) with the wavelength in 830 and 690 nm. The optical properties include the absorption coefficient, reduced scattering coefficient and hemodynamic responses. It shows that the correlation between the reduced scattering coefficient and the brain infarction volume from histochemical stain is high in 830 nm, and moderate in 690 nm. Besides, there is significant difference in reduced scattering coefficient between infarction region at cortex and subcortex and that at subcortex only or sham group. These results show that NIRS can be an effective tool to evaluate ischemic stroke.