Abstract: ObjectiveTo observe the ultrastructures of vessel and endotheliocyte in the early stage(2 h after stimulation finished) after acute mechanical middle cerebral artery(MCA) vasospasm in cats.MethodsThe right MCA of 6 cats were mechanically stimulated using a small smooth stainless steel nail in the field acrossing the olfactory tract for 30 min.The diameter of MCA was recorded by metrical ocular of microscope.The changes of the perfusion index of brain tissue were observed through the Laser Doppler flowmetry monitor fixed on the skull.The ultrastructure of vessel and endotheliocyte were investigated through the electron microscope.ResultsThe diameter of MCA decreased to 68.78% of normal.2 h later,the diameter of MCA recovered.The perfusion index of the cortex surface decreased to 42.59% of normal and up to 61.87% 2 h later.The chromatin of endotheliocyte congregated to the side and formed the lunular body.The heaves of mitochondria(MIT) are blurry 2 hours after the mechanical stimulation.ConclusionThe persistent mechanical stimulation can cause acute cerebral vasospasm,which may involve the apoptosis of endotheliocyte of MCA.It is important to reduce the mechanical stimulus to the cerebral vessel in order to avoid acute cerebral vasospasm during clinical and basic craniotomy.

Key words: cerebrum, vasospasm, endotheliocyte, apoptosis, craniotomy, cat