title: Acute changes in muscle blood flow and concomitant muscle damage after an intramuscular administration.
abstract: OBJECTIVE
  The intramuscular route (IM) is widely used but commonly induces injection site muscle damage. This study investigates the hemodynamic changes in an acute lesion induced by the IM administration of propylene glycol (PG) in rabbits.
  
  
  METHODS
  Control groups received 1, 2, or 3 ml of PG (IM). Others were pretreated with pancuronium, dantrolene, indomethacin, or SR140333 and then received 2 ml of PG. The muscle blood flow (MBF) was assessed using fluorescent microspheres before and at 15, 45, 60, 90 min, 3 and 6 h after IM administration. Different areas within the muscle damage were quantified.
  
  
  RESULTS
  Muscle contractions as well as a transient but major MBF increase were observed at the injection site. All treatments reduced hyperemia by up to 81% (dantrolene, 15 min) at 15, 45, and 90 min (p < 0.05). MBF had returned to basal values in all groups at 6 h. The central necrotic area was not modified, but peripheral damage (8.0 +/- 1.3 g) was reduced by dantrolene, indomethacin, and SR140333 (p < 0.05), but not by pancuronium.
  
  
  CONCLUSIONS
  Muscle contraction and hyperemia are not responsible for muscle damage at the injection site, which is the multifactorial phenomenon, involving intracellular calcium and inflammation.
authors.affiliation: UMR 181 Physiopathologie et Toxicologie Expérimentales INRA-ENVT, Ecole Nationale Véterinaire, BP 87614, 31076 Toulouse Cedex 03, France.
authors.forename: Pierre Jean
authors.initials: PJ
authors.lastname: Ferré
authors.forename: Eckart
authors.initials: E
authors.lastname: Thein
authors.forename: Isabelle
authors.initials: I
authors.lastname: Raymond-Letron
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Toutain
authors.forename: Hervé Pierre
authors.initials: HP
authors.lastname: Lefebvre
mesh_terms: D000818:Animals; D007273:Injections, Intramuscular; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects* / Q000502:physiology; D019946:Propylene Glycol / Q000008:administration & dosage*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology
chemical_list: D019946:Propylene Glycol