This Is AuburnElectronic Theses and Dissertations

The effect of concurrent and non-concurrent (delayed) administration of mepivacaine hydrochloride and triamcinolone acetonide on inflamed equine osteochondral and synovial explants in co-culture




Boorman, Sophie

Type of Degree

Master's Thesis


General Veterinary Medicine


During equine lameness investigation, intra-articular administration of a local anesthetic followed by a corticosteroid is common for diagnosis and treatment of osteoarthritis (OA). Anecdotally, veterinarians are advised to separate diagnosis and treatment to allow recovery of articular tissues from the inflammatory effect of the local anesthetic; however, no scientific evidence supports this need for rest. 5 geldings and 1 mare (aged 3-18 years) were euthanized for reasons unrelated to the study. From each horse, 48 synovial explants and 12 osteochondral explants were harvested from the stifles and transferred to a 12-well plate (2 wells per group, 2 synovial explants and 1 osteochondral explant per well). Explants were stimulated with 10 μg/ml recombinant equine interleukin-1β (IL-1β) and 10 μg/ml tumour necrosis factor-α (TNF-α). They were treated as 6 groups: unstimulated control, stimulated control, triamcinolone acetonide (TA, 10-6 M), mepivacaine hydrochloride (MH, 4.4 mg/ml), MH + TA (concurrent) and MH + TA (delayed). The delayed group was treated with MH and, six days later, treated with TA. Media were replenished and analysed every 3 days for 9 days total. ELISA analyses for markers of tissue cytotoxicity (lactate dehydrogenase, LDH), inflammatory eicosanoids (prostaglandin E2, PGE2), and markers of matrix degradation (matrix metalloproteinase 13, MMP-13 and dimethylmethylene blue assay, DMMB, for glycosaminoglycan, GAG) were performed. Data were analysed with 2-way ANOVA or mixed-effects models with Tukey’s multiple comparisons. There were no differences in LDH, PGE2, MMP-13 and GAG between delayed and concurrent groups at any time point; no differences were found in culture medium levels of cytotoxicity, inflammation or matrix degradation between explants treated concurrently with MH and TA and those that had a 6-day delay between MH and TA treatments. In this model, no benefit of a 6-day delay between local anaesthetic and corticosteroid treatments was found.