[Optical coherence tomography angiography and microvessel density quantification in penumbra after traumatic brain injury in rats].

OBJECTIVE

To observe the dynamic changes of microvascular injury and repair in the penumbra of traumatic brain injury (TBI) rats with effective cerebral perfusion microvascular imaging using optical coherence tomography angiography (OCTA).

METHODS

Transparent closed cranial windows were placed in craniotomy rats after TBI caused by weight drop. All the rats in TBI group and control group underwent head MRI examination on the first postoperative day, and the changes of cerebral cortical microvessel density were measured by OCTA through cranial windows on d0, d2, d4, d6, and d8. On the second day after the operation, the same number of rats in the two groups were selected to complete the immunohistochemical staining of brain tissue with pimonidazole, an indicator of hypoxia.

RESULTS

MRI T2W1 and immunohistochemical staining demonstrated that edema and hypoxia in the traumatic brain tissue extended deeply throughout the entire cortex. OCTA showed that the cortical surface veins of the rats in both groups were significantly dilated and tortuous after operation, and recovered to the postoperative day level on d8. The effective perfusion microvessel density of the rats in both groups gradually recovered after a temporary decrease, and the TBI group decreased from 39.38%±4.48% on d0 to 27.84%±6.01% on d2, which was significantly lower than that on d0, d6, and d8 ( < 0.05). The highest value was 61.71%±7.69% on d8, which was significantly higher than that on d0, d2, and d4 ( < 0.05). The control group decreased from 44.59%±7.78% on d0 to 36.69%±5.49% on d2, which was significantly lower than that on d0, d6, and d8 ( < 0.05). The highest value was 51.92%±5.96% on d8, which was significantly higher than that on d2, and d4 ( < 0.05). Comparing the two groups, the effective perfusion microvessel density in the TBI group was significantly lower than that in the control group on d2 (=0.021), and significantly higher than that in the control group on d8 (=0.030).

CONCLUSION

OCTA can be used as a method of imaging and measurement of effective perfusion microvessels in the injured cerebral cortex of TBI rats. After TBI, the effective perfusion microvessel density in the wound penumbra gradually recovered after decreasing, and increased significantly on d8.