Attenuation of ischemic inflammatory response in mouse brain using an adenoviral vector to induce overexpression of interleukin-1 receptor antagonist.
It has been demonstrated that administration of an interleukin-1 receptor antagonist protein (IL-1ra) reduces ischemic brain injury; however, the detrimental mechanism initiated by interleukin-1 (IL-1) in ischemic brain injury is unclear. In this study, we used mice that were transfected to overexpress human IL-1ra to elucidate the role of IL-1 in the activation of the inflammatory response after middle cerebral artery occlusion (MCAO). Myeloperoxidase (MPO) activity and immunohistostaining were used as a marker of polymorphonuclear leukocytes (PMNL) infiltration. Adenoviral vector (1 x 10(9) particles) was administered by injection into the right lateral ventricle in mice. Five days later, MCAO was performed on the mice using a suture technique. Permanent MCAO was achieved for 24 hours in the Ad.RSVIL-1ra-transfected. Ad.RSVlacZ-transfected, and saline (control) mice. Myeloperoxidase activity was quantified in each region and localization of MPO was determined by immunohistochemistry. After 2 hours of MCAO, the surface cerebral blood flow was reduced to 13.5% +/- 3.4%, 10.75% +/- 2.6%, and 10.9% +/- 2.6% of baseline in the ischemic hemisphere in Ad.RSVIL-1ra-transfected, Ad.RSVlacZ-transfected, and saline-treated mice, respectively. The MPO activity in the ischemic hemisphere in the Ad.RSVlacZ group was similar to that in the saline control group (cortex: 0.40 +/- 0.22 versus 0.33 +/- 0.11; basal ganglia: 0.46 +/- 0.23 versus 0.49 +/- 0.17; P > 0.05); however, it was significantly reduced in the Ad.RSVIL-1ra group (cortex: 0.18 +/- 0.07; basal ganglia: 0.26 +/- 0.15; P < 0.05). Myeloperoxidase immunohistochemistry showed that the massive accumulation of MPO-positive cells in the ischemic cortex, striatum, and corpus callosum regions was greatly attenuated in Ad.RSVIL-1ra-transfected mice. Our results indicate that Ad.RSVIL-1ra-transfected mice provide a useful tool to study the mechanism of action of IL-1. The MPO activity assay and immunostaining after 24 hours of focal ischemia were significantly reduced in IL-1ra gene-transfected mice, suggesting that IL-1 may play an important role in the activation of inflammatory cells during focal cerebral ischemia.
Yang
G Y
GY
Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor 48109-0532, USA.
Liu
X H
XH
Kadoya
C
C
Zhao
Y J
YJ
Mao
Y
Y
Davidson
B L
BL
Betz
A L
AL
D000256:Adenoviridae; D000818:Animals; D015415:Biomarkers; D001921:Brain / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D002545:Brain Ischemia / Q000276:immunology / Q000517:prevention & control / Q000628:therapy*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D007249:Inflammation; D053590:Interleukin 1 Receptor Antagonist Protein; D002546:Ischemic Attack, Transient / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000276:immunology / Q000473:pathology; D009195:Peroxidase / Q000032:analysis; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000096:biosynthesis; D012795:Sialoglycoproteins / Q000096:biosynthesis*
D015415:Biomarkers; C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins; D009195:Peroxidase