Objective To investigate the effects of hyperbaric oxygen (HBO on the expressions of endothelin-1 (ET-1),endothelial nitric oxide synthase (eNOS)and endothelin A receptor(ETAR) in cerebral circulation blood vessel in the rabbit model of cerebral ischemia.Methods Forty healthy adult New Zealand rabbits were randomly divided into 2 groups;the surgical group (n =30) and the control group (n =10).The rabbits in the surgical group were further divided into the HBO + cerebral ischemia group (n =15) and the simple cerebral ischemia group (n =15) in accordance with different treatment methods.In the surgical group,cerebral ischemia model was established by thread embolus method.The HBO + cerebral ischemia group was exposed to HBO at a pressure of 0.22 MPa(2.2 ATA)for 60 minutes,one session a day,for a succession of 3 days.In the sham surgical group,neck vessel was only separated and the incision was soon sutured.The animals in the sham surgical group and the cerebral ischemia group did not receive HBO exposure,had normal diet and left there intact for 3 days.Three days later,all the animals were sacrificed,and then immunohistochemical staining was performed by using ET-1,ETAR and eNOS antibodies,and observations were made on the expressions of ET-1,eNOS and ETAR in the internal carotid artery and basilar artery of the 3 groups.Results Experimental results indicated that there were expressions of ET-1,eNOS and ETAR in the internal carotid artery and basilar artery after HBO exposure.As compared with those of the sham surgical group and the cerebral ischemia group,the expression levels of ET-1 and ETAR in the internal carotid artery (51.6 ± 2.1,53.4 ± 1.5) of the HBO + cerebral ischemia group were obviously higher than those in the basilar artery (20.3 ± 2.6,24.3 ± 1.7),and eNOS expression level in the basilar artery (52.1 ± 2.3) was significantly higher than that in the internal carotid artery(22.3 ± 1.2).Conclusions HBO exposure could enhance ET-1 and ETAR expression levels in the internal carotid artery,and could improve eNOS expression in basilar artery,resulting in anterior circulation contraction and posterior circulation dilation.

Objective To investigate the effects of hyperbaric oxygen (HBO on the expressions of endothelin-1 (ET-1),endothelial nitric oxide synthase (eNOS)and endothelin A receptor(ETAR) in cerebral circulation blood vessel in the rabbit model of cerebral ischemia.Methods Forty healthy adult New Zealand rabbits were randomly divided into 2 groups;the surgical group (n =30) and the control group (n =10).The rabbits in the surgical group were further divided into the HBO + cerebral ischemia group (n =15) and the simple cerebral ischemia group (n =15) in accordance with different treatment methods.In the surgical group,cerebral ischemia model was established by thread embolus method.The HBO + cerebral ischemia group was exposed to HBO at a pressure of 0.22 MPa(2.2 ATA)for 60 minutes,one session a day,for a succession of 3 days.In the sham surgical group,neck vessel was only separated and the incision was soon sutured.The animals in the sham surgical group and the cerebral ischemia group did not receive HBO exposure,had normal diet and left there intact for 3 days.Three days later,all the animals were sacrificed,and then immunohistochemical staining was performed by using ET-1,ETAR and eNOS antibodies,and observations were made on the expressions of ET-1,eNOS and ETAR in the internal carotid artery and basilar artery of the 3 groups.Results Experimental results indicated that there were expressions of ET-1,eNOS and ETAR in the internal carotid artery and basilar artery after HBO exposure.As compared with those of the sham surgical group and the cerebral ischemia group,the expression levels of ET-1 and ETAR in the internal carotid artery (51.6 ± 2.1,53.4 ± 1.5) of the HBO + cerebral ischemia group were obviously higher than those in the basilar artery (20.3 ± 2.6,24.3 ± 1.7),and eNOS expression level in the basilar artery (52.1 ± 2.3) was significantly higher than that in the internal carotid artery(22.3 ± 1.2).Conclusions HBO exposure could enhance ET-1 and ETAR expression levels in the internal carotid artery,and could improve eNOS expression in basilar artery,resulting in anterior circulation contraction and posterior circulation dilation.

Objective To investigate the establishment of focal cerebral ischemia model in rabbits with the improved suture method.Methods A total of 45 healthy and clean adult New Zealand rabbits were divided into either a sham operation group (n =5) or a model group (n =40) using random number table method before modeling,and the sex was not limited.The self-made head ends of 2-0 fishing lines dipped in paraffin were used as the sutures.The external carotid artery was cut and inserted into a intracranial artery through the internal carotid artery and blocked the origin of middle cerebral artery.The neurological function score was performed after 6 h.The neurological deficit scores ≥2 was successful modeling.The rabbits were killed by anesthesia.The brain slices were stained with 2％ 2,3,5-triphenyl tetrazolium chloride solution.The infarct foci were observed.The diameters of suture head and the depth of suture insertion were compared in the model rabbits with successful modeling,failure,and death in the model group.Results There were 40 rabbits in the model group,six of them died,including 4 died of subarachnoid hemorrhage within 4 h after operation,and 2 died from anesthetic accident.The mortality rate was 15.0％.Seven rabbits failed,mainly because of cerebral vasospasm and the insertion depth of suture was insufficient.Twenty-seven had successful modeling,and the success rate was 67.5％.All the rabbits in the sham operation group survived.The diameter of the suture head and insertion depth in the successful modeling rabbits were compared with the death and failure outcome in rabbits.The difference was statistically significant (diameter:0.52 ± 0.14 mm vs.0.45 ±0.40 mm and 0.58 ±0.17 mm;depth:5.49 ±0.17 cm vs.6.04 ± 0.11 cm and 4.26 ±0.30 cm;all P ＜ 0.05).Conclusions The improved suture method can successfully prepare the focal cerebral ischemia model of middle cerebral artery in rabbits.The method is simple.Its repeatability and practicability are better.