Kurzfassung

Increased mortality after stroke is associated with development
of brain edema. The aim of the present study was to
examine the contribution of endothelial myosin light chain
(MLC) phosphorylation to hypoxia-induced blood–brain barrier
(BBB) opening. Measurements of trans-endothelial electrical
resistance (TEER) were performed to analyse BBB integrity in
an in vitro co-culture model (bovine brain microvascular
endothelial cells (BEC) and rat astrocytes). Brain fluid content
was analysed in rats after...Increased mortality after stroke is associated with development
of brain edema. The aim of the present study was to
examine the contribution of endothelial myosin light chain
(MLC) phosphorylation to hypoxia-induced blood–brain barrier
(BBB) opening. Measurements of trans-endothelial electrical
resistance (TEER) were performed to analyse BBB integrity in
an in vitro co-culture model (bovine brain microvascular
endothelial cells (BEC) and rat astrocytes). Brain fluid content
was analysed in rats after stroke induction using a two-vein
occlusion model. Dihydroethidium was used to monitor intracellular
generation of reactive oxygen species (ROS) in BEC.
MLC phosphorylation was detected using immunohistochemistry
and immunoblot analysis. Hypoxia caused a decrease
of TEER values by more than 40%, which was
prevented by inhibition of the MLC-kinase (ML-7, 10 lmol/L).
In addition, ML-7 significantly reduced the brain fluid content in
vivo after stroke. The NAD(P)H-oxidase inhibitor apocynin
(500 lmol/L) prevented the hypoxia-induced TEER decrease.
Hypoxia-dependent ROS generation was completely abolished
by apocynin. Furthermore, ML-7 and apocynin blocked
hypoxia-dependent phosphorylation of MLC. Our data demonstrate
that hypoxia causes a breakdown of the BBB in vitro
and in vivo involving ROS and the contractile machinery.
Keywords: blood–brain barrier, endothelial cells, myosin light
chain, reactive oxygen species, stroke.» weiterlesen» einklappen