Continuous digital hypothermia initiated after the onset of lameness prevents lamellar failure in the oligofructose laminitis model.

Equine veterinary journal

PubMedID: 24004323

Van Eps AW, Pollitt CC, Underwood C, Medina-Torres CE, Goodwin WA, Belknap JK. Continuous digital hypothermia initiated after the onset of lameness prevents lamellar failure in the oligofructose laminitis model. Equine Vet J. 2013;.
REASONS FOR PERFORMING STUDY
Prophylactic digital hypothermia reduces the severity of acute laminitis experimentally, but there is no evidence for its efficacy as a treatment once lameness has already developed.

OBJECTIVES
To investigate the therapeutic effects of digital hypothermia, applied after the onset of lameness, in an experimental acute laminitis model.

STUDY DESIGN
Randomised, controlled (within subject), blinded, experimental trial.

METHODS
Eight Standardbred horses underwent laminitis induction using the oligofructose model. Once lameness was detected at the walk, one forelimb (CRYO) was continuously cooled, with the other forelimb (NON-RX) maintained at ambient temperature. Dorsal lamellar sections (proximal, middle and distal) harvested 36 h after the onset of lameness/initiation of cryotherapy were analysed by 2 blinded observers: laminitis pathology was scored (0 [normal] to 4 [severe]) and morphometric analyses were also performed.

RESULTS
Median [interquartile range] histological scores were greater (P<0.05) in NON-RX (proximal 2.8 [2.5-4]; middle 3.5 [2-4]; distal 2.5 [2-3.8]) compared with CRYO limbs (proximal 0.5 [0.5-1.4]; middle 1 [0.6-1]; distal 0.75 [0.5-1]). There was complete physical separation of lamellar dermis from epidermis (score of 4) in 4 of the NON-RX feet at one or more section level(s), which was not observed in any CRYO sections. Histomorphometry was thus limited to sections that remained intact; there was a trend of increased total- (TELL) and secondary- (SELL) epidermal lamellar length, and decreased secondary epidermal lamellar width (SELW) in NON-RX limbs compared with CRYO at all 3 levels; differences were significant (P<0.05) for SELL and SELW in the distal sections.

CONCLUSIONS
Digital hypothermia reduced the severity of lamellar injury and prevented lamellar structural failure (complete dermo-epidermal separation) when initiated at the detection of lameness in an acute laminitis model. This study provides the first evidence to support the use of therapeutic digital hypothermia as a treatment for acute laminitis.