Cartilage-Sparing Properties of Equine Omega Complete in an Organ Culture Model of Cartilage Inflammation.

The purpose of this study was to determine anti-inflammatory and/or chondroprotective effects of Equine Omega Complete (EOC) on cartilage explants stimulated with lipopolysaccharide (LPS). Explants were aseptically prepared from the intercarpal joints of 17 market-weight pigs and placed in culture at 37°C for a total of 120 hours. For the final 96 hours, explants were conditioned with a simulated digestion extract of EOC (0, 36 or 180 µL/mL), and for the final 48 hours explants were stimulated with LPS (0 or 15µg/mL). Media was removed and replaced every 24 hours. Samples from the final 48 hours were analyzed for biomarkers of cartilage inflammation (prostaglandin E2 [PGE2] and nitric oxide [NO]) and cartilage structure (glycosaminoglycan [GAG]). At the end of the culture period cartilage explants were stained for an estimate of cell viability. Stimulation of unconditioned explants with LPS significantly increased media concentrations of PGE2, GAG and NO compared with that from unstimulated explants. LPS stimulation did not significantly affect cell viability. Both concentrations of EOC prevented significant LPS-stimulated cartilage release of GAG without impairing chondrocyte viability. No other effects of treatment were observed. These data provide evidence for a non-cytotoxic, chondroprotective effect of EOC in cartilage. This in vitro experiment supports the use of EOC in protecting against the detrimental effects of inflammation on cartilage structure.

Culturing Articular Cartilage Explants in the Presence of Autologous Adipose Tissue Modifies Their Inflammatory Response to Lipopolysaccharide.

The purpose of the current study was to explore the effect of autologous adipose tissue on cartilage responses to lipopolysaccharide (LPS). We hypothesized that LPS elicits an inflammatory response in cartilage, and that response is augmented in the presence of adipose tissue. Furthermore, we hypothesized that this augmented inflammatory response is due, at least in part, to increased exposure of cartilage to adipose tissue-derived c3a. Porcine cartilage explants from market-weight pigs were cultured in the presence or absence of autologous adipose tissue for 96 hours, the final 48 hours of which they were stimulated with LPS (0 or 10 µg/mL). Adipose tissue explants were also cultured alone, in the presence or absence of LPS. Media from all cartilage treatments was assayed for c3a/c3a des Arg, PGE2, GAG, and NO, and the viability of cartilage tissue was determined by differential fluorescent staining. Media from adipose tissue explants was assayed for c3a/c3a des Arg and PGE2. LPS produced a significant increase in PGE2, GAG, and NO production when cartilage was cultured in the absence of adipose tissue. Coculture of adipose tissue prevented a significant increase in PGE2 in cartilage explants. There was no effect of adipose tissue on LPS-induced GAG or NO, but the presence of adipose tissue significantly reduced cell viability in LPS-stimulated cartilage explants. Adipose tissue explants from lean animals reduced inflammatory responses of cartilage to LPS via a c3a/c3a des Arg-independent mechanism and were associated with a significant decline in cell viability. Thus, contrary to our hypothesis, adipose tissue from lean animals does not augment the inflammatory response of cartilage to stimulation by LPS. The mechanism of modulatory effects of adipose tissue on LPS-induced increase in PGE2 and decline in chondrocyte viability requires further research but appears to have occurred via a mechanism that is independent of adipocentric c3a/c3a des Arg.

Welfare-improving enrichments greatly reduce hens' startle responses, despite little change in judgment bias.

Responses to ambiguous and aversive stimuli (e.g. via tests of judgment bias and measures of startle amplitude) can indicate mammals' affective states. We hypothesised that such findings generalize to birds, and that these two responses co-vary (since both involve stimulus evaluation). To validate startle reflexes (involuntary responses to sudden aversive stimuli) and responses in a judgment bias task as indicators of avian affective state, we differentially housed hens with or without preferred enrichments assumed to improve mood (in a crossover design). To control for personality, we first measured hens' baseline exploration levels. To infer judgment bias, control and enriched hens were trained to discriminate between white and dark grey cues (associated with reward and punishment, respectively), and then probed with intermediate shades of grey. For startle reflexes, forceplates assessed responses to a light flash. Judgment bias was only partially validated: Exploratory hens showed more 'optimism' when enriched, but Non-exploratory hens did not. Across all birds, however, startle amplitudes were dramatically reduced by enrichment (albeit more strongly in Exploratory subjects): the first evidence that avian startle is affectively modulated. Startle and judgment biases did not co-vary, suggesting different underlying mechanisms. Of the two measures, startle reflexes thus seem most sensitive to avian affective state.