Hindlimb laminar inflammatory response is similar to that present in forelimbs after carbohydrate overload in horses.
BACKGROUND
A significant proinflammatory response is known to occur in the forelimb lamina after carbohydrate administration. As the hindlimbs are often less affected by laminitis compared with the forelimbs, we assessed hindlimb inflammatory response in the early stages of carbohydrate-induced laminitis to determine whether differences in the response existed.


OBJECTIVE
To determine whether a similar proinflammatory response occurs in the hindlimb laminae to that previously reported for the forelimb.


METHODS
Archived laminar samples from 12 horses administered 17.6 g of starch (85% corn starch, 15% wood flour)/kg bwt via nasogastric tube that were anaesthetised either after developing a temperature >38.9°C (DEV; n = 6) or at the onset of Obel grade 1 lameness (OG1; n = 6) were used in addition to 6 control horses (CON) that were anaesthetised 24 h after administration of water. Real-time quantitative polymerase chain reaction for selected proinflammatory mediators and MAC387 immunohistochemistry were performed. The data were analysed nonparametrically to compare groups.


RESULTS
Increases in laminar MAC387-positive leucocytes and laminar messenger ribonucleic acid (mRNA) concentrations (P<0.05) for interleukin-1β, interleukin-6, cyclo-oxygenase-2, chemokine (C-X-C motif)ligand (CXCL)1 and CXCL8 were present in both fore- and hindlimb laminae from horses with OG1 lameness. Both CXCL1 and CXCL8 were also increased in forelimb and hindlimb laminae in the DEV horses.


CONCLUSIONS
Administration of carbohydrate resulted in a similar inflammatory response in the hindlimb laminae to that previously reported for the forelimb laminae. These findings suggest that other factors, such as weightbearing, may play an important role in the development of laminitis after a systemic inflammatory condition develops.


CONCLUSIONS
Evidence of inflammation in the hindlimb laminae suggests that the hindfeet should be addressed in the septic horse at risk for laminitis; however, laminitis is often less severe in the hindlimbs due to other factors, such as weightbearing and hoof angle.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, USA.
B S
BS
Leise
R R
RR
Faleiros
M
M
Watts
P J
PJ
Johnson
S J
SJ
Black
J K
JK
Belknap
D000818:Animals; D005534:Foot Diseases / Q000139:chemically induced / Q000473:pathology / Q000662:veterinary*; D005552:Forelimb / Q000473:pathology*; D006614:Hindlimb / Q000473:pathology*; D006724:Hoof and Claw / Q000187:drug effects / Q000473:pathology; D006734:Horse Diseases / Q000139:chemically induced* / Q000473:pathology; D006736:Horses; D007249:Inflammation / Q000139:chemically induced / Q000473:pathology / Q000662:veterinary*; D013213:Starch / Q000009:adverse effects*
D013213:Starch