title: Mitogen-activated kinase pathway activation in epidermal lamellae in the acute stages of carbohydrate overload laminitis models and the effect of regional deep hypothermia on signalling pathways.
abstract: BACKGROUND
  In sepsis models, mitogen-activated protein kinases (MAPKs) are reported to incite inflammatory injury to tissues and are purported to be a therapeutic target.
  
  
  OBJECTIVE
  To assess MAPK signalling in lamellae in sepsis-related laminitis (SRL) at different time points after induction of laminitis via carbohydrate overload, and to determine the effect of regional deep hypothermia (RDH) on MAPK signalling.
  
  
  METHODS
  In vitro study using archived tissue samples.
  
  
  METHODS
  Lamellar concentrations of MAPKs were assessed in archived lamellar samples from 2 studies: 1) the starch gruel model of SRL with 3 groups (n = 6/group) of horses (control, onset of fever [DEV] Obel Grade 1 lameness [OG1]); and 2) from limbs maintained at ambient (AMB) and hypothermic (ICE) temperatures (n = 6/group) in animals given a bolus of oligofructose. Immunoblotting and immunolocalisation were used to assess lamellar concentrations and cellular localisation of total and activated (phosphorylated) forms of p38 MAPK, extracellular-regulated kinase (ERK) 1/2, and stress-activated protein kinase/c-jun N terminal kinase (SAPK/JNK) 1/2.
  
  
  RESULTS
  Lamellar samples had statistically significant increased concentrations of activated ERK 1/2 at the onset of OG1 laminitis (vs. control) in the starch gruel model, but showed no significant change between ICE and AMB limbs in the RDH model. Phospho-SAPK/JNK 1/2 exhibited a similar significant increase in the OG1 samples, but was also increased in ICE (vs. AMB) limbs. No statistically significant changes in lamellar p38 MAPK concentrations were noted.
  
  
  CONCLUSIONS
  Increased concentrations of activated ERK 1/2 and SAPK/JNK in the acute stages of SRL indicate a possible role of these signalling proteins in lamellar injury. Signalling related to ERK 1/2 and SAPK/JNK 1/2 pathways should be further investigated to determine if these play a detrimental role in laminitis and may be therapeutic targets to be manipulated independently of RDH.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Gardner
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Kelly
authors.affiliation: School of Veterinaary Science, University of Queensland, Australia.
authors.forename: A W
authors.initials: AW
authors.lastname: van Eps
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Burns
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Watts
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Belknap
mesh_terms: D000818:Animals; D003080:Cold Temperature; D004040:Dietary Carbohydrates / Q000009:adverse effects; D004817:Epidermis; D005534:Foot Diseases / Q000139:chemically induced / Q000378:metabolism / Q000662:veterinary*; D006724:Hoof and Claw / Q000378:metabolism* / Q000473:pathology; D006734:Horse Diseases / Q000139:chemically induced* / Q000378:metabolism; D006736:Horses; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism / Q000662:veterinary*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D004040:Dietary Carbohydrates; D020928:Mitogen-Activated Protein Kinases
keywords: digital lamellae; horse; inflammation; laminitis; mitogen-activated protein kinase; sepsis