title: Increased activity of Rho kinase contributes to hemoglobin-induced early disruption of the blood-brain barrier in vivo after the occurrence of intracerebral hemorrhage.
abstract: This study is to examine whether the activation of Rho kinase (ROCK) accounts for hemoglobin (Hb)-induced disruption of blood-brain barrier (BBB) after the occurrence of intracerebral hemorrhage. A model of intracerebral injection of Hb was established in rats. Changes in the levels of mRNA of RhoA, ROCK2 and matrix metalloproteinase-9 (MMP-9) were measured using quantitative real-time polymerase chain reaction. Protein expression of RhoA, ROCK2, claudin-5 and MMP-9, as well as ROCK activity, were determined using Western blotting. Immunohistochemical assay was performed to visualize the expression of RhoA, ROCK2, claudin-5 and MMP-9 in endothelial cells. Hb injection produced a significant increase in BBB permeability and water content in the brain. Significant reduction of claudin-5 expression was detected by Western blotting and immunofluorescence in Hb group. The levels of RhoA and ROCK2 were significantly up-regulated from 6 h to 12 h after Hb injection and were concomitant with the increase in ROCK activity. Immunofluorescence double staining showed enhanced p-myosin light chain immunoreactivity but diminished claudin-5 staining in endothelial cells. Significant up-regulation of MMP-9 expression was detected after Hb injection, and statistical analyses further confirmed a positive correlation of MMP-9 expression with ROCK activity. The results showed that ROCK was activated in endothelial cells by Hb. This may account for the early disruption of the BBB via up-regulation of p-myosin light chain expression and aggravation of injuries to TJ proteins. The activation of ROCK may also increase MMP-9 expression, thereby leading to further BBB disruption.
authors.affiliation: Department of Neurosurgery, The Fifth Affiliated Hospital of Southern Medical University Guangzhou 510900, China ; The National Key Clinic Specialty; Department of Neurosurgery, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Zhujiang Hospital, Southern Medical University Guangzhou 510282, China.
authors.forename: Zhenghao
authors.initials: Z
authors.lastname: Fu
authors.affiliation: The National Key Clinic Specialty; Department of Neurosurgery, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Zhujiang Hospital, Southern Medical University Guangzhou 510282, China.
authors.forename: Yizhao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University Guangzhou Guangdong Province 510515, China.
authors.forename: Fengzhen
authors.initials: F
authors.lastname: Qin
authors.affiliation: Gaoqing Campus of Central Hospital of Zibo, Gaoqing People's Hospital Zibo City, Shandong Province, P.R. China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Yang
authors.affiliation: Guangdong 999 Brain Hospital, Guangzhou City Guangdong Province, P.R. China.
authors.forename: Xinqing
authors.initials: X
authors.lastname: Deng
authors.affiliation: The National Key Clinic Specialty; Department of Neurosurgery, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Zhujiang Hospital, Southern Medical University Guangzhou 510282, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Ding
authors.affiliation: The National Key Clinic Specialty; Department of Neurosurgery, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Zhujiang Hospital, Southern Medical University Guangzhou 510282, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Neurosurgery, The Fifth Affiliated Hospital of Southern Medical University Guangzhou 510900, China.
authors.forename: Weiguang
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, The Fifth Affiliated Hospital of Southern Medical University Guangzhou 510900, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhu
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D002543:Cerebral Hemorrhage / Q000378:metabolism* / Q000473:pathology; D062507:Claudin-5 / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006454:Hemoglobins / Q000008:administration & dosage*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D062725:Tight Junction Proteins / Q000378:metabolism; D015854:Up-Regulation; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D062507:Claudin-5; D006454:Hemoglobins; D062725:Tight Junction Proteins; D054460:rho-Associated Kinases; D020780:Matrix Metalloproteinase 9; D020742:rhoA GTP-Binding Protein
keywords: Blood-brain barrier; Rho kinase; hemoglobin; intracerebral hemorrhage; matrix metalloproteinase; tight junction