Investigation of characters on functions and pathology of primary brainstem injury in rabbits / 重庆医学

ABSTRACT

Objective To study characters of pathology associated with functional alteration of primary brainstem injury (PBI) at different injury severities in rabbits .Methods Animal model of graded PBI was produced using rabbits .Animals were di‐vided into five groups ,group Ⅰ to Ⅳ with an increase of impact power ,10 cases in each group ,and the control group with 5 cases . The pathology characters of PBI were investigated combining dissection observation with unaided eye ,tissue HE histochemical stai‐ning and electron microscope .Results Slight brainstem injury were observed in group Ⅰ ,and pathological results showed regional subarachnoid hemorrhage (SAH) ,stripping of regional cerebral pia mater ,a few petechial hemorrhage in surface ,nerve cell edema , normal medulla sheath and axon roughly .The brainstem injuries were apparent in group Ⅱ ,and the pathological changes indicated SAH in sheet ,petechial and sheeted hemorrhage in surface ,and slight swelling and vacuoles in nerve cells .The brainstem injuries were observed obviously in group Ⅲ ,exhibiting thick SAH ,petechial and sheeted hemorrhage in surface and inside ,degeneration of nerve cells ,abruption of axon ,and atrophy of axoplasm .Eight of ten animals died of respiratory depression induced by brainstem in‐jury in group Ⅳ ,presenting thick hemorrhage in subarachnoid surrounding brainstem ,the whole brainstem injured ,microscopically with multiple small hemorrhage ,nerve cells only residual nuclei ,myelin lamellar severe stratification and fracture ,and axonal tran‐section ,disintegration .No abnormal pathological changes were shown in control group .Conclusion The impacts to brainstem with higher powers lead to more manifest functional and more severe pathological changes ,with an alternation of injury location from surface to deep .