Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis
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| Language: | English |
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The Ohio State University / OhioLINK
2020
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1587579850590509 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu1587579850590509 |
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oai_dc |
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NDLTD |
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English |
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NDLTD |
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Veterinary Services |
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Veterinary Services Sullivan, Stasia N. Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| author |
Sullivan, Stasia N. |
| author_facet |
Sullivan, Stasia N. |
| author_sort |
Sullivan, Stasia N. |
| title |
Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| title_short |
Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| title_full |
Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| title_fullStr |
Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| title_full_unstemmed |
Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis |
| title_sort |
corticosteroid effects on equine deep digital flexor tendon cell viability and biosynthesis |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2020 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1587579850590509 |
| work_keys_str_mv |
AT sullivanstasian corticosteroideffectsonequinedeepdigitalflexortendoncellviabilityandbiosynthesis |
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1719457221098602496 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu15875798505905092021-08-03T07:14:30Z Corticosteroid Effects on Equine Deep Digital Flexor Tendon Cell Viability and Biosynthesis Sullivan, Stasia N. Veterinary Services Introduction: Navicular disease is a common cause of forelimb lameness in horses. Degenerative lesions involving the fibrocartilage on the flexor surface of the navicular bone and opposing dorsal surface of the deep digital flexor tendon (DDFT) are common sources of lameness associated with navicular disease. Intrasynvoial/intrabursal corticosteroids are commonly administered in clinical management of these horses due to their potent anti-inflammatory properties. While corticosteroid-induced cytotoxicity and matrix dysregulatory effects in articular cartilage/chondrocytes are well-recognized, their effects on tenotoxicity and matrix metabolism of tendon tissue/cells are less known. Objectives: To investigate the comparative effects of triamcinolone acetonide (TA) and methylprednisolone acetate (MPA) on metabolic activity and viability of resident cells present in dorsal fibrocartilaginous zone of deep digital flexor tendon (FC-DDFT) and fibrocartilage on the flexor surface of the navicular bone (FC-NB) in an explant model. Secondly, the effects of methylprednisolone on matrix mRNA expression and collagen, glycosaminoglycan contents of DDFT-derived cells under non-inflammatory conditions were evaluated in an in vitro aggregate cell culture model. FC-DDFT and FC-NB explants and DDFT-derived cells required for this research were harvested/isolated from forelimbs of 5 equine cadavers (age, 9 to 15 years) without evidence of musculoskeletal disease.Methods: Explants were incubated with medium (control) or TA (0.6 and 6 mg/ml) or MPA (0.5 and 5 mg/ml) for 6 and 24 hours. Explant metabolic activity and cell viability were measured using the Alamar Blue assay and Calcein-Sytox stained live-dead assay, respectively and compared among treatments at each time. Third passage DDFT-derived cells were maintained as aggregates in ultra-low attachment tissue culture plates and were cultured for 6 days. Next, DDFT-derived cells were treated with 0.05mg/mL and 0.5mg/mL MPA or untreated culture medium for 24 hours. Cells were collected for total RNA isolation and RT-PCR analyses of tendon ECM (collagen type I, type III and COMP) and chondrocytic (sox-9, collagen type II, aggrecan) mRNA expression. Total GAG contents (aggregate and cell culture medium) and soluble collagen content in culture medium were measured. Results: TA (at both concentrations) did not significantly change the metabolic activity and cell viability of FC-DDFT explants compared to controls. TA at 6 mg/ml significantly reduced the metabolic activity (P = 0.02; 0.01) and cell viability (P = 0.041; 0.01) of FC-NB at both time points compared to controls. MPA at both concentrations significantly reduced the metabolic activity and cell viability of FC-DDFT and FC-NB explants at 24 hours; whereas, only 5 mg/ml MPA was toxic at 6-hour timepoint. Based on the observations of the explant study and the increased cytotoxic effects of MPA relative to TA, the second objective of this thesis research evaluated the effects of MPA on DDFT-derived cell phenotype (tendon ECM and chondrocytic mRNA expressions) and ECM synthesis (total collagen and GAG contents) during in-vitro aggregate culture under non-inflammatory conditions. At the concentrations used in this study, the chondrocytic mRNA expression were more susceptible to MPA treatment than tendon ECM mRNA expression. However, when collagen and GAG contents were measured, there were no significant difference between MPA-treated and control DDFT-derived cells. Conclusions: TA was less cytotoxic to FC-DDFT and FC-NB cells compared to MPA. The explant model was suitable for evaluating the effects of commonly used medications on deep digital flexor tendon and navicular fibrocartilage. While MPA affected the gene expression profile of DDFT-derived cells, the collagen and GAG contents were unchanged with MPA treatment. These results lay a foundation for future in vivo work and subsequent clinical recommendations. 2020-10-02 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1587579850590509 http://rave.ohiolink.edu/etdc/view?acc_num=osu1587579850590509 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |