Study on the cerebral microcirculation of rats with subarachnoid hemorrhage by using laser speckle technique

Abstract

Objective To study the value of laser speckle technique in measuring blood flow changes in the cerebral microcirculation of rats with subarachnoid hemorrhage (SAH). Methods Rat double blood injection method was used to establish the model of SAH. Rats were divided into control group, SAH 5-day group, SAH 7-day group, saline 5-day group and saline 7-day group. After sensory nerve function examination, cerebral cortical blood flow was measured by laser speckle technique, and apoptotic index and electron microscopy were detected. SPSS 17.0 statistical software was used to make statistical analysis by variance analysis or non-parametric test. Results SAH 5-day group showed significant sensory dysfunction. There were significant differences between SAH 5-day group (12.100±1.287) and control group (15), SAH 7-day group (14.700±0.675), saline 5-day group (14.900±0.316) and saline 7-day group (15) (Z values were -4.059, -3.655, -3.908, -4.059, respectively; respectively P<0.01); Electron microscopy showed that the morphology of neurons in the control group and saline injection groups was basically normal; neurons in the SAH 5-day group showed obvious edema and extensive neuronal degeneration or necrosis; neurons in the SAH 7-day group showed slight swelling and some neurons had degeneration or necrosis. There were obvious apoptotic cells in cerebral cortex of SAH groups. The apoptotic index of SAH 5-day group [(19.870±1.909)%] and control group [(1.840±0.474)%], SAH 7-day group [(13.770±1.924)%], saline 5-day group [(1.740±0.299)%], saline 7-day group [(1.790±0.407)%] had statistical differences (t values were 28.985, 7.117, 29.670, 29.291, respectively; respectively P<0.01). SAH 7-day group and control group, SAH 5-day group, saline 5-day group, saline 7-day group had statistical differences (t values were 19.037, -7.117, 19.537, 19.263, respectively; respectively P<0.01). Cerebral cortical blood flow in SAH groups decreased, and the most obvious decrease was found in SAH 5-day group (64.000±6.218), compared with control group (106.000±13.081), SAH 7-day group (75.700±8.274), saline 5-day group (105.100±13.169), saline 7-day group (104.100±10.609). There were significant differences (t values were -9.170, -3.575, -8.924, -10.312, respectively; successively P<0.01, 0.05, 0.01, 0.01). There were significant differences between SAH 7-day group and control group, SAH 5-day group, saline 5-day group and saline 7-day group (t values were -6.191, 3.575, -5.978 and -6.675, respectively; successively P<0.01, 0.05, 0.01, 0.01, 0.01). Conclusion Laser speckle technique is suitable for studying the blood flow changes of cerebral microcirculation in SAH rats. Key words: Subarachnoid hemorrhage; Cerebral microcirculation; Cerebral blood flow; Laser speckle