| Objectives:To establish rabbit jugular vein thrombosis (JVT) model by injecting with thrombin.To investigate the changes of diameter of jugular vein(JV), intracranial pressure(ICP), cerebral blood flow velocity(CBFV) and brain tissue after the jugular vein thrombosis through rabbit jugular vein thrombosis model,and to search for the possible pathophysiological mechanisms,then to explain the impact on intracranial circulatory system.Methods: Forty rabbits were divided into 4 groups randomly,left jugular vein thrombosis (LJVT) group,right jugular vein thrombosis(RJVT) group,bilateral jugular vein thrombosis (BJVT) groupand control group. Before thrombosis:(1) We made an incision about 5cm long on the head for every rabbit,and opened a bone window of 4mm×8mm nearby sagittal line 3mm,then removed the bone and keeped the dura intact.Adult vein remaining needlleiv of 18# was sticked into subarachnoid space toward frontal pole 5mm depth and fixed underneath the fur properly.Then little heparin saline was injected into the needlleiv. The needlleiv was connected with the invasive blood pressure module of ECG. Cerebrospinal fluid pressure represented the intracranial pressure.(2)Pulse probe of 4MHz was placed at the bone window to measure the blood flow velocity of anterior cerebral artery (ACA) by Transcranial Doppler ultrasonic diagnostic apparatus made in U.S. VIASYS company.(3)The JV diameter of every rabbit was measured by color Doppler ultrasonography apparatus produced by U.S. GE company. thrombosis:Interal jugular vein and external jugular vein were dissected on each animal in the experimental groups,and were cliped by two vascular clips at the inferior segment about 2cm of jugular vein. Then the internal jugular vein was injected with thrombin 0.1ml (25u), external jugular vein was injected with thrombin 0.3ml (75u) in the blocked phase.The vascular folders were removed after 20min. Interal jugular vein and external jugular vein were only dissected in the contral group, then sutured.After thrombosis: (1)To confirm whether thrombus model is established or not,each animal was examinated through color Doppler ultrasound and diameter of jugular vein was measured at the same time.(2) ICP and CBFV of ACA were measured at 0h,4h,8h,12h,24h,48h,72h postoperatively in the same way. (3)Animals were decapitated by 4% Klorvess Liquid after 1 week.Periatal lobe brain tissue was dislodged after removing the skull with the rongeur,then was fixed by 4% formalin for 24h.Pathological changes of brain was observed after paraffin embedding,sliceing and HE staining.Results:(1) After Color Doppler ultrasound examination of each animal by the neck, the experimental groups showed there was an echo area of moderate intensity in rabbit jugular vein ,which was no color flow, it can not be completely closed through the probe pressor test.Animal models of jugular vein thrombus were confirmed established Successfully. Successful rate was 100%. The control group showed there was a laminar flow with same color in the jugular vien, vascular permeability sound good, the probe pressure test can be completely closed. This meaned that blood flow of internal jugular vein and external jugular vein was influent.(2) Compared with the prothrombolic,the diameter of internal jugular vein and external jugular vein was enlarged significantly in the experimental groups(P<0.01).There was no Significant difference(P>0.05) in the control group. (3)ICP of LJVT and RJVT increased slightly(P<0.05) and reached to maximum(P<0.01) at 4h,then decreased to normal levelat 12h(P>0.05). ICP of BJVT increased remarkablely(P<0.01) and reached peak(P<0.01) at 12h,then decreased slowly ,and keeping higher level within 72h(P<0.01).ICP of control group fluctuated but were no apparent difference(P>0.05) after operation.(4) CBFV of LJVT and RJVT accelerated at oh,4h (P<0.01),and it reached the fastest speed(P<0.01) at 24h and return to normal(P>0.05) at 48h. CBFV of BJVT speed-up (P<0.01)immediately after thrombosis.It reached the maximum(P<0.01) at 24h,then keeping higher level(P<0.01) within 72h. CBFV of control group did not changed after operation(P>0.05).(5)LJVT showed that glial cells proliferated,glial cell addicted neuronal cell and cerebrovascular thrombosised.RJVT was found that glial cells proliferated,the surrounding space broadened, capillary congested and cerebrovascular thrombosised.BJVT manifested that cerebrovascular thrombosised,lymphocytes infiltrated,perivascular cuffs formed. There was no abnormity on neuronal cell of control group.Conclusions:(1) Through injecting with thrombin , The jugular vien thrombus model was not only fast, reliable, simple, and repeatable, but also with high successful rate.The type of thrombin was consistent with clinical pathology.(2) he diameter of internal jugular vein and external jugular vein were significantly enlarged after rabbit jugular vein thrombosis. Jugular vein thrombosis can impede intracranial venous return. (3)Due to intracranial venous obstruction, ICP increased and CBFV accelerated after rabbit jugular vein thrombosis. Unilateral jugular vein thrombosis may be faster to establish their own compensation, ICP and CBFV returned to normal in a short time; bilateral jugular vein thrombosis, ICP and CBFV can not be compensated within 72h, remain higher than normal levels.(4)Jugular vein thrombosis may induce complex results that cerebrovascular thrombosised,lymphocytes infiltrated, glial cells proliferated,et al.
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