Relevance of synovial fluid chondroitin sulphate as a biomarker to monitor polo pony joints.

Osteoarthritis (OA) of the metacarpophalangeal joint is the most common articular disease in polo ponies leading to early retirement. A biomarker that would discriminate between pathological and physiological changes secondary to exercise could be helpful in OA prevention. The aim of this study was to investigate the effects of polo training on synovial fluid biomarkers of inflammation and cartilage turnover in polo ponies of different skill levels. Synovial fluid samples were collected from metacarpophalangeal joints of polo ponies before and during the polo season (320 d). Nucleated cells, soluble protein, prostaglandin E2 (PGE2), glycosaminoglycans (GAG), and urea were measured. The main synovial fluid GAG are chondroitin sulphate (CS, ~25 µg/mL) and hyaluronic acid (HA, ~400 µg/mL). After a polo match, a transitory increase in protein and PGE2, but not CS and HA, occurred (expressed as urea ratio), returning to basal levels in 24 h. During the polo season, the number of synovial fluid nucleated cells was always in the normal range. Increases in protein and HA occurred during the initial 40 to 80 d, returning to basal levels afterwards. In contrast, in polo prospects the concentration of CS steadily increased during the season. Long-term follow-up revealed that the synovial fluid CS was significantly higher in polo ponies that developed joint diseases within 24 months following our study. In conclusion, CS seems to be an early marker of articular cartilage damage.

L'arthrose (OA) de l'articulation métacarpophalangienne est la maladie articulaire la plus fréquente chez les poneys de polo menant à la retraite anticipée. Un biomarqueur qui était discriminateur entre les changements pathologiques et physiologiques secondaires au exercice pourrait être utile pour la prévention de l'OA. L'objectif de la présente étude était examiner les effets de l'activité de polo sur les biomarqueurs de l'inflammation et de le métabolisme de la cartilage dans le liquide synovial des poneys de polo de différents niveaux de qualification. Le SF était obtenu à partir de les articulations métacarpophalangiennes de poneys de polo, avant et pendant la saison de polo (320 jours). Les cellules nucléés, protéine soluble, prostaglandine E2 (PGE2), glycosaminoglycanes (GAG) et l'urée ont été mesurés. Les principaux GAG de le liquide synovial sont le chondroïtine sulfate (CS, ~25 µg/mL) et l'acide hyaluronique (HA, ~400 µg/mL). Après un match de polo, ocorru une augmentation transitoire de la protéine et de la PGE2, mais pas de CS et de HA (exprimé comme le raison d'urée), qui a retourné aux niveaux basal dans 24 h. Pendant la saison de polo, le numero de cellules nucléés dans le liquide synovial était toujours normaux. La protéine et le HA augmentaient pendant les premiers 40­80 jours, mais tous les deux sont retournés aux niveaux de base plus tard. En contraste, dans le group de jeunes poneys (G1), la concentration de CS a augmenté régulièrement pendant la saison. Accompagnant à long terme avait révéle que le CS de liquide synovial était significativement plus élevée chez les poneys de polo que, dans les 24 mois suivants, avaient developpé des maladies articulaires. En conclusion, le CS du liquide synovial semble être un marqueur précoce des destructions de la cartilage articulaire.(Traduit par les auteurs).

Influência do exercício na indução da apoptose e necrose das células do líquido sinovial de eqüinos atletas / Exercise induced apoptosis and necrosis in the synovial fluid cells of athletic horses

Examinaram-se os efeitos do estresse mecânico na resposta inflamatória e adaptativa dos tecidos articulares de cavalos atletas. O líquido sinovial foi colhido das articulações metacarpofalangeanas de eqüinos atletas antes, 3, 6 e 24 horas após o exercício, assim como de um grupo controle (cavalos não exercitados). A porcentagem de apoptose/necrose, o TNF-a e a PGE2 foram determinados pelo ensaio de AnexinaV/Iodeto de Propídeo, bioensaio (L929) e ELISA, respectivamente. Os resultados mostraram que a contagem total de células nucleadas foi sempre menor no grupo controle em relação ao grupo atleta (P<0,05). Observaram-se aumentos na porcentagem de células em apoptose (P<0,05) e necrose (P<0,05), concentração de PGE2 (P<0,05) e proteína sinovial (P<0,05), e diminuição da concentração de TNF-a (P<0,05) após 3 horas do término do exercício. O grupo atleta apresentou grau moderado de inflamação articular após o exercício intenso. Esta resposta dos tecidos articulares frente ao insulto mecânico do exercício, com maior intensidade às 3 horas após término da atividade esportiva e retornando à normalidade 24 horas após, revela a capacidade da adaptação articular ao estresse físico, em eqüinos atletas.

The effects of biomechanical stress on inflammatory and adaptative responses of articular tissues in athletic horses were investigated. Synovial fluid was collected from the metacarpophalangeal joints of athletic horses before exercise and 3, 6, 24 hours after exercise, and as well as from the control group (without exercise). Apoptosis/necrosis percentage, TNF-a and PGE2 were determined by annexin V/PI assay, bioassay (L929) and ELISA, respectively. The results showed that total leukocyte count was higher in the athletic group when is compared with the control group. Three hours after the exercise was done there were increases of cellular apoptosis (P>0.05) and necrosis (P<0.05) percentage, PGE2 concentration (P<0.05) and protein concentration (P<0.05), and the TNF-a level has dropped. The athletic group showed moderate level of joint inflammation after the strenuous exercise. This articular tissue response to biomechanical insult due to the exercise, with high intensity after 3 hours after training associated with normality after 24 hours, reveals the articular adaptation to physical stress in athletic horses.

Effect of intraluminal distention on microvascular perfusion in the equine small colon.

OBJECTIVE: To determine the effect of experimental intraluminal distention on microvascular perfusion of the small colon in horses. ANIMALS: 6 mixed-breed healthy horses (mean age [+/- SDI, 9.1 +/- 2 years). PROCEDURE: Under general anesthesia, the small colon was exposed by celiotomy and 3 segments were demarcated. In 1 of these segments, intraluminal obstruction was created by placement of a latex balloon inflated to a pressure of 40 mm Hg (obstructed segment). The other segments were the sham-operated segment and the control segment. Microvascular perfusion was evaluated in the mucosal, submucosal, muscular, and serosal layers by injection of 15 microm-diameter colored microspheres into branches of the caudal mesenteric artery. Recovery of microspheres was performed by tissue digestion, washing, and centrifugation. Distribution of microspheres in the intestinal layers was evaluated by direct observation of stained frozen sections by light microscopy. RESULTS: A significant reduction was observed in total microvascular perfusion of obstructed segments, which was 26.4% of that of control segments. This reduction was not evident in the mucosal layer. CONCLUSIONS AND CLINICAL RELEVANCE: Intraluminal distention of the equine small colon wall can promote ischemia by a reduction in microvascular perfusion in the intestinal wall. Intestinal layers do not seem to be affected to the same extent, because the absolute value for mucosal perfusion did not decrease in the obstructed segment.

Enterorrafias em plano aposicional convencionale com adesivo à base de cianoacrilato no cólon descendente de eqüinos / Conventional appositional pattern and cyanoacrylate tissue adhesive in descending colon enterorrhaphy in horses

Em eqüinos, as enterotomias no cólon descendente säo necessárias para remover enterólitos, corpos estranhos e material alimentar compactado que näo podem ser removidos por técnicas conservativas. Este segmento intestinal possui um suprimento sangüíneo pobre, além de predisposiçäo a complicaçöes pós-operatórias relacionadas à contaminaçäo bacteriana. Assim, este estudo foi conduzido com o objetivo de efetuar avaliaçöes clínicas e anatomopatológicas do emprego de adesivo tecidual à base de cianoacrilato no cólon descendente de eqüinos, comparando-o a uma técnica de sutura aposicional convencional. A intervençäo cirúrgica foi realizada em 15 animais posicionados em decúbito lateral direito, através de laparotomia pelo flanco esquerdo, sob anestesia geral inalatória. Após a exteriorizaçäo do cólon descendente, foram realizadas duas enterotomias de cinco centímetros de extensäo cada, distanciadas 20cm uma da outra. Os animais foram aleatoriamente distribuídos em cinco tempos de observaçäo de três animais cada e sacrificados aos três, sete, 14, 35 e 70 dias de pós-operatório. O adesivo butil-2-cianoacrilato e o fio de poliglactina 910 mostraram-se igualmente apropriados para uso em enterorrafias desse órgäo, sendo que o fio de poliglactina 910 provocou inflamaçäo inicial mais intensa que o cianoacrilato e, mais tardiamente, ambos causaram inflamaçäo granulomatosa do tipo corpo estranho observada, primeiramente, junto ao fio de poliglactina 910 (7º dia) e, a partir do 35º dia, ao redor do cianoacrilato