| ObjectiveThe mechanism of blood brain barrier（BBB）injury caused by cerebral ischemia/reperfusion（I/R）has been thoroughly studied,but there are still some unsolved problems.β-1,3-galactosyltransferase 2（B3galt2）is expressed in the brain,but its role in the pathogenesis of cerebral ischemia remains unclear.The purpose of this study is to investigate whether B3galt2 has a protective effect on BBB injury in mice after I/R,and clarify its mechanism.MethodsMiddle cerebral artery occlusion（MCAO）model was established by embolization method.We assessed the infarct volume by 2,3,5-triphenyltetrazolium chloride（TTC）staining.Neurological score and rotating rod test were performed to observe the changes of neurological function.Evans blue（EB）leakage used to detect observe the changes of BBB permeability.Meanwhile,FITC-Dextran exudation was used to detect observe the permeability of small molecular weight substances.The levels of B3galt2、Occludin、Claudin-5、TGF-β1、TGF-βR（II）、p-Smad2/3、p-Smad1/5/9、ERK1/2、JNK were detected by Western blot.CD31,occludin and claudin-5 were observed by immunofluorescent staining.ResultsThe results showed that the levels of B3galt2 in cerebral microvessels increased at 12h,24h and 72h after reperfusion.Overexpression of B3galt2（LV-B3galt2）could reduce the infarct size after I/R and improve neurological function.In addition,LV-B3galt2 had a neuroprotective effect on BBB injury,and LV-B3galt2 could inhibit the degradation of microvascular Occludin and Claudin-5.Compared with wild-type（WT）mice,B3galt2-/+mice showed severe BBB impairment,neurological impairment,and decreased levels of TGF-β1,TGF-βR（II）,and p-Smad2/3 proteins in microvessels after I/R.Human Recombinant TGF-β1（r-TGF-β1）was injected into lateral ventricles and reduced BBB damage in B3galt2-/+mice after I/R.The results suggest that B3galt2 has a protective effect on I/R injury,and the potential mechanism may be related to the TGF-β1/TGF-βR（II）/p-Smad2/3 signaling pathway.ConclusionsB3galt2 overexpression has a protective effect on BBB injury after cerebral ischemia in mice.B3galt2 regulates ischemia induced-BBB injury through TGF-β1/TGF-βR（II）/p-Smad2/3 signaling pathway. |
