Laminar Inflammation Responses in the Oligofructose Overload Induced Model of Bovine Laminitis

Abstract

Bovine laminitis causes substantial economic losses and animal welfare problems in dairy farms worldwide. Previously published studies have reported that the inflammatory response plays a central role in the pathogenesis of the disease. To our knowledge, inflammation associated with bovine laminitis induced by high levels of exposure to oligofructose (OF) has not been reported and characterized. In fact, the disease manifestations in this model closely approximate those of clinical laminitis. The objective of this study was to characterize the inflammatory response in OF-induced bovine laminitis. A total of 12 Chinese Holstein dairy heifers were utilized in this study. The heifers were randomly divided into two groups, treatment (n = 6) and control (n = 6). The treatment group heifers were administered OF solutions via a stomach tube (dose: 17 g/kg of body weight). Upon development of a lameness score of 2 with consecutive positive reactions in the same claw, they would be humanely euthanized. Control heifers were administered deionized water (dose: 2 L/100 kg of body weight) and humanely euthanized at 72 h. Real-time quantitative PCR (qPCR) assays were performed to determine the messenger RNA (mRNA) concentrations of inflammatory mediators in the lamellae. Concentrations of interleukin (IL)-1β, IL-6, IL-8, C-X-C motif chemokine ligand-1 (CXCL-1), macrophage cationic peptide-2 (MCP-2), E-selectin, intercellular adhesion molecule-1 (ICAM-1), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase-1 (iNOS-1), and plasminogen activator inhibitor-1 (PAI-1) were significantly increased (P < 0.05) in the treatment group. No significant difference was found for tumor necrosis factor alpha (TNF-α), IL-10, CXCL-6, and MCP-1. These results demonstrated and characterized the laminar inflammatory response leading to the pathogenesis of bovine laminitis at the early stages.

Change in Proteolytic Profile in Heifers After Oligofructose Overload

“…However, the role of these proteinases was unclear in OF induced bovine laminitis. Previously, we demonstrated the activation of blood neutrophil and the inflammation reaction of lamellar tissue after OF overload (17,18). This study aimed to investigate the changes in the proteolytic profile in plasma and lamellar tissue in heifers with OF-induced laminitis.…”

Data_Sheet_1.docx

“…By contrast, the gene expressions of laminar ADAMTS-4 and ADAMTS-5 significantly increased in the heifers with OF-induced laminitis. Using the same sample, we previously reported increased laminar IL-1 and IL-6 gene expression (33). An increase in the gene expression of these interleukins may induce increases in ADAMTS-4 and ADAMTS-5 expression because IL-1 and IL-6 reportedly contribute to the induction of ADAMTS-4 and ADAMTS-5 in the cartilage (60).…”

“…In our published literature, we have already proved that the bovine laminitis was successfully established using the OFinduced model, and laminitic heifers developed characteristic histological lesions in the lamellae, including BM destruction and detachment, stretching of epidermal lamellae and changes in basal cell morphology (33). Herein, we utilized the same batch of lamellae tissue as that literature, then conducted further gene-level measurement of representative MPs and TIMPs.…”

“…An overloaded ingestion of OF (a type of non-structural carbohydrate), which can rapidly reduce the pH of rumen liquid, compromises intestinal barrier functions and results in the death of numerous Gram-negative bacteria. The free lipopolysaccharide (LPS) translocates from the digestive tract into the peripheral circulation (32), leading to systemic inflammatory responses and multiple organ damage, including laminitis (33), rumenitis (34), and synovitis (35).…”

“…One of the primary mechanisms of MMP-2/MMP-9 regulation is at the level of transcription (20,39), especially they could be induced response to multiple stimuli, including proinflammatory cytokines, transforming growth factors, and LPS (40). In our previous studies, we utilized the same batch of lamellae samples as this study, and reported the increased gene expression of multiple proinflammatory mediators (33). These results may provide a possible explanation to the increases in MMP-2 and MMP-9 expression observed in the present study.…”