title: Pathophysiology of blast-induced ocular trauma in rats after repeated exposure to low-level blast overpressure.
abstract: BACKGROUND
  The incidence of blast-induced ocular injury has dramatically increased due to advances in weaponry and military tactics. A single exposure to blast overpressure (BOP) has been shown to cause damage to the eye in animal models; however, on the battlefield, military personnel are exposed to BOP multiple times. The effects of repeated exposures to BOP on ocular tissues have not been investigated. The purpose of this study is to characterize the effects of single or repeated exposure on ocular tissues.
  
  
  METHODS
  A compressed air shock tube was used to deliver 70 ± 7 KPa BOP to rats, once (single blast overpressure [SBOP]) or once daily for 5 days (repeated blast overpressure [RBOP]). Immunohistochemistry was performed to characterize the pathophysiology of ocular injuries induced by SBOP and RBOP. Apoptosis was determined by quantification activated caspase 3. Gliosis was examined by detection of glial fibrillary acidic protein (GFAP). Inflammation was examined by detection of CD68.
  
  
  RESULTS
  Activated caspase 3 was detected in ocular tissues from all animals subjected to BOP, while those exposed to RBOP had more activated caspase 3 in the optic nerve than those exposed to SBOP. GFAP was detected in the retinas from all animals subjected to BOP. CD68 was detected in optic nerves from all animals exposed to BOP.
  
  
  CONCLUSIONS
  SBOP and RBOP induced retinal damage. RBOP caused more apoptosis in the optic nerve than SBOP, suggesting that RBOP causes more severe optic neuropathy than SBOP. SBOP and RBOP caused gliosis in the retina and increased inflammation in the optic nerve.
authors.affiliation: Ocular Trauma Task Area, U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas, USA.
authors.forename: Jae Hyek
authors.initials: JH
authors.lastname: Choi
authors.forename: Whitney A
authors.initials: WA
authors.lastname: Greene
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Johnson
authors.forename: Mikulas
authors.initials: M
authors.lastname: Chavko
authors.forename: Jeffery M
authors.initials: JM
authors.lastname: Cleland
authors.forename: Richard M
authors.initials: RM
authors.lastname: McCarron
authors.forename: Heuy-Ching
authors.initials: HC
authors.lastname: Wang
mesh_terms: D000399:Air Pressure; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D017209:Apoptosis; D001753:Blast Injuries / Q000378:metabolism / Q000503:physiopathology*; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D005131:Eye Injuries / Q000378:metabolism / Q000503:physiopathology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000378:metabolism / Q000503:physiopathology*; D007124:Immunoenzyme Techniques; D008297:Male; D020221:Optic Nerve Injuries / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000293:injuries*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D053148:Caspase 3; D005904:Glial Fibrillary Acidic Protein; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C505410:Casp3 protein, rat
keywords: apoptosis; blast overpressure; blast-induced ocular trauma; gliosis; optic neuropathy