Bachelor of Science (BS), Ohio University, 2023, Chemistry

There is a need for a skin model which combines the natural physiology of skin and uses less mice. Natural physiology is obtained using fresh, intact skin explants sourced from living organisms such as humans or mice. This work focused on the standardization and characterization of an in vitro mouse skin explant model for studying ultraviolet (UV) damage and repair mechanisms in skin. In this study, we established a protocol to use skin explants from discarded mice after euthanasia; these skin explants are cuts of intact dermal and epidermal skin suspended in cell culture medium and maintained in vitro. Our tissue explants maintain in vivo skin's characteristics and physiological responses for short periods of incubation time, but use less mice. In addition, our model allows us to study DNA damage and repair and still analyze different incubation periods post-sUV.

Committee: Lauren McMills Dr. (Advisor); Verónica Bahamondes Lorca Dr. (Advisor); Shiyong Wu Dr. (Advisor) Subjects: Biochemistry; Chemistry

Master of Science, The Ohio State University, 2021, Comparative and Veterinary Medicine

Septic arthritis is an important cause of lameness in cattle. There are currently no antimicrobials labeled for treatment of septic arthritis in cattle in the United States. In addition to the well established anti-inflammatory and chondroanabolic properties of platelet-rich plasma (PRP), recent in-vitro experimental studies have also highlighted the immune-metabolic effects and antimicrobial properties of PRP when used alone, and in conjunction with antimicrobials. Given the regulatory restrictions associated with antimicrobial use in cattle, PRP is of potential therapeutic benefit to this common clinical problem. The objective of this study was to evaluate the chondroprotective effects of ampicillin/sulbactam (Amp-S), autogenous PRP alone (PRP) or combined with Amp-S (PRP+Amp-S) in an explant model of bovine Staphylococcus aureus induced septic arthritis. Autogenous PRP was prepared prior to euthanizing 6 cows. Articular cartilage explants were collected from stifle joints and incubated in synovial fluid with 1 x 105 CFU/mL S. aureus ATCC 25923. Cartilage explants were incubated with S. aureus infected synovial fluid alone (S. aureus control), or S. aureus infected synovial fluid with treatments PRP (25% culture medium volume), Amp-S (2 mg/mL Unasyn™), or PRP+Amp-S for 24 hours. Explant chondrocyte viability, metabolic activity and GAG content were measured via live-dead assay/confocal microscopy, Alamar blue assay and DMMB assay, respectively. Data was analyzed with one-way ANOVA (p≤0.05). Cartilage explants inoculated with S. aureus (control) resulted in 64±10.5% dead cells. Treatment PRP (26±2.8%), Amp-S (25±10.6%) and PRP+Amp-S (22±4%) significantly decreased cell death. There was no significant difference in explant cell death and metabolic activity among the treatments. These results indicate that PRP, Amp-S, and PRP+Amp-S mitigated S. aureus-induced chondrocyte death in this in-vitro explant model of bovine septic arthritis. This data serves as a foundatio (open full item for complete abstract)

Committee: Sushmitha Durgam BVSc, MS, PhD (Advisor); Andrew Niehaus DVM, MS (Advisor); Dubraska Diaz-Campos DVM, PhD (Committee Member); Jeffrey Lakritz DVM, PhD (Committee Member); Joseph Lozier DVM, MS (Committee Member) Subjects: Osteopathic Medicine; Veterinary Services