You-xin Ji*,Ke-tao Lan,Chuan-xin Geng,Xiao Zou,and Song-ping Wang
Department of Medical Oncology,Qingdao Central Hospital,Second Affiliated Hospital of Qingdao University,Qingdao 266042,China
BRAIN ischemia stroke is a devastating disease,with more than 10% stroke patients either severely disabled or dead.Although rodent filament middle cerebral artery occlusion (MCAO)model can mimic human brain ischemic stroke well,its wide use was restricted by difficulty in surgery,especially in ligating pterygopalatine artery (PPA).Twenty-seven male Sprague-Dawley rats were randomly divided into A,B,C groups (n=9).All the rats were performed MCAO surgery with sutures of difference sizes.Group A used 4-0 blocking suture plus ipsilateral PPA block,group B used 3-0 blocking suture plus ipsilateral common carotid artery (CCA) block,and group C used 3-0 suture plus ipsilateral PPA block.Twenty-seven male C57BL/6 wild type mice were also randomly divided into a,b,c groups.Group a used 5-0 blocking suture plus ipsilateral PPA block,group b used 6-0 blocking suture plus ipsilateral CCA block,group c use 6-0 suture plus ipsilateral PPA block.All the sutures were blared by flame,making one side of the suture to a round and smooth tip to avoid blood vessels damage.Dry the suture in an oven at 60°C after soaked in poly-L-lysine solution (0.1% w/v in water) for 15 minutes.Cerebral blood flow (CBF) was recorded before and after surgery.Twenty-four hours after the surgery,the brains were harvested,cut into 2-mm section,and stained with 2,3,5-triphenyltetrazolium chloride.CBF,brain infarct volume,and brain morphology were compared among groups.CBF of the occluded side was found significant decreased by 80%after MCAO in each group (P<0.05).The CBF of the un-occluded side was slightly increased after MCAO,but with no significant difference (P>0.05).The infarct volume in rats was 605.5 ± 116.3 mm3in group A,676.9 ± 33.4 mm3in group B,and 669.8 ± 50.6 mm3in group C,significantly different between 3-0 suture groups (group B,C) and 4-0 suture group (group A) (P<0.05),but not between group B and group C.In mice,the infract volume in group b and group c were 67.0 ± 9.4 mm3and 64.7 ± 9.1 mm3respectively (P>0.05).In group a using the 5-0 suture,the internal carotid artery (ICA) was easily penetrated and the subarachnoid hemorrhage (SAH) rate was as high as 33.3%,affecting the infarction result.The brain infarct volume and morphology were much stable and constant in rats using 3-0 sutures and mice using 6-0 sutures,either with CCA or PPA block.Suture-induced MCAO animal model is most commonly used,but the small operation area and deep PPA impose difficulty for ligation,especially in mouse model.Poly-L-lysine treatment does not increase the diameter of the suture,but the blood vessel tissue adherence to the suture,making PPA completely blocked at its ICA origin.Suture size also influences the infarct size and volume.The infarct volume,positions,and variation were identical with either CCA or PPA blocking in both rats and mice.It is therefore not necessary to ligate PPA when using poly-L-lysine-treated suture,making filament-induced MCAO animal model easier to establish.SAH resulting from perforation of the intracranial portion of the ICA or the anterior cerebral artery represents a typical complication of the MCAO model.It could alter the infarct volume and general conditions of the animal,leading to changes in animal behavior and biological results,thus should be excluded from study.Suture size is an important factor in SAH.In conclusion,pretreated suture of appropriate size with CCA blocking is easy to perform and able to provide stable brain infarction result in both rats and mice.It could serve as a substitute for the more complicated PPA blocking method in establishing permanent rodent stroke model.Its application in temporary stroke model needs further study.
Chinese Medical Sciences Journal2011年4期