M1/70 attenuates blood-borne neutrophil oxidants, activation, and myofiber damage following stretch injury.
The purpose of this study was to determine the role of the CD11b-dependent respiratory burst in neutrophil oxidant generation and activation, interleukin-8 (IL-8) production, and myofiber damage after muscle stretch injury by using the monoclonal antibody M1/70 to block this pathway. Twelve male New Zealand White rabbits were randomly assigned to a treatment group: M1/70 (n = 6), IgG isotype control (n = 3), or saline control (n = 3). After intravenous injection of the assigned agent under gas anesthesia, a standardized single-stretch injury was created in the right tibialis anterior, whereas the left tibialis anterior underwent a sham surgery. Blood-borne neutrophil oxidant generation and CD11b receptor density and plasma IL-8 levels were measured pre- and 24 h postinjury. Damage was assessed histologically at the hematoma site by counting torn myofibers. M1/70 group demonstrated decreased blood-borne neutrophil oxidant generation (P < 0.05) and CD11b receptor density (P < 0.05), an increase in plasma IL-8 concentration (P < 0.01), and less torn myofibers (P < 0.01) compared with IgG isotype or saline control groups. These data indicate that 1). CD11b-dependent respiratory burst is a major source of oxidants produced by the neutrophil, and that treatment with M1/70 2). attenuates neutrophil activation status, 3). increases plasma IL-8 concentration, and 4). minimizes myofiber damage 24 h postmuscle stretch injury.
Brickson
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S
Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53706, USA. sbrickson@education.wisc.edu
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Schell
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Olabisi
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St  Pierre Schneider
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B
Best
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TM
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D039481:CD11b Antigen / Q000378:metabolism / Q000502:physiology; D002452:Cell Count; D002470:Cell Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000473:pathology*; D018482:Muscle, Skeletal / Q000293:injuries* / Q000473:pathology*; D018375:Neutrophil Activation / Q000187:drug effects*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism*; D011817:Rabbits; D016897:Respiratory Burst / Q000187:drug effects; D013708:Tendon Injuries / Q000473:pathology
D000911:Antibodies, Monoclonal; D039481:CD11b Antigen; D016209:Interleukin-8; C483346:M1-70 monoclonal antibody; D016877:Oxidants