Biochemical and hematologic changes in whole blood from Brazilian horses stored in citrate-phosphate-dextrose-adenine pouches for up to 28 days.

BACKGROUND: Anaerobic cellular metabolism causes a series of structural and physiologic changes during storage that could compromise post-transfusion viability, reducing the safety of using blood stored for an extended period. OBJECTIVE: We aimed to follow the biochemical and hematologic alterations of equine blood stored in plastic bags containing citrate-phosphate-dextrose-adenine (CPDA-1) for up to 28 days. METHODS: Whole blood samples (450 mL) were collected from 20 Brazilian Saddle horses into CPDA-1 pouches and stored between 2°C and 6°C in a blood bank. On days 0, 7, 14, 21, and 28 of storage, blood samples were taken and submitted for biochemical (sodium [Na+ ], potassium [K+ ], glucose, and lactate) and hematologic (hemoglobin [Hb], hematocrit [HCT], mean corpuscular volume [MCV], percent hemolysis [% hemolysis]) analyses. RESULTS: The only time the blood pH levels dipped below 7 was after D21 of storage, and the levels were significantly lower than those on the first storage day (D0). Potassium concentrations showed significant increases from D7 and then remained increased throughout the experimental period. Chloride and lactate concentrations revealed a significantly increased trend from D7 that was maintained over time. Mean corpuscular volumes increased significantly on D7 and D14 and, thereafter, remained stable. The mean % hemolysis increased on D28, which was significantly higher than D0. No bacterial growth was found in any pouch after 28 days of storage. CONCLUSIONS: Significant and gradual biochemical changes were observed in equine whole blood during prolonged storage. These changes could compromise the clinical conditions of patients requiring transfusion. In vivo studies are needed to evaluate the effects as well as survival rates and efficacy of transfused red blood cells in recipients.

Effects of endurance racing on horse plasma extracellular particle miRNA.

BACKGROUND: Physical exercise is an essential factor in preventing and treating metabolic diseases by promoting systemic benefits throughout the body. The molecular factors involved in this process are poorly understood. Micro RNAs (miRNAs) are small non-coding RNAs that inhibit mRNA transcription. MiRNAs, which can participate in the benefits of exercise to health, circulate in plasma in extracellular particles (EP). Horses that undergo endurance racing are an excellent model to study the impact of long-duration/low intensity exercise in plasma EP miRNAs. OBJECTIVES: To evaluate the effects of 160 km endurance racing on horse plasma extracellular particles and their miRNA population. STUDY DESIGN: Cohort study. METHODS: We collected plasma from five Arabian horses during five time-points of an endurance ride. Extracellular particles were purified from plasma and characterised by electron microscopy, resistive pulse sensing (qNano) and western blotting. Small RNAs were purified from horse plasma EP, and sequencing was performed. RESULTS: Endurance racing increased EP concentration and average diameter compared to before the race. Western blotting showed a high concentration of extracellular vesicles proteins 2 hours after the race, which returned to baseline 15 hours after the race. MicroRNA differential expression analysis revealed increasing levels of eca-miR-486-5p during and after the race, and decreasing levels of eca-miR-9083 after the end. CONCLUSIONS: This study adds new data about the variation in plasma EP concentrations after long-distance exercise and brings new insights about the roles of exercise-derived EP miRNAs during low-intensity endurance exercise.

Do hematologic constituents really increase due to endurance exercise in horses? / O exercício de resistência realmente leva ao aumento dos constituintes sanguíneos em equinos?

The aim of this study was to evaluate the behavior of blood constituents in a group of horses that successfully completed long endurance rides in tropical conditions. Jugular vein puncture was done to collect blood before, during and after rides. Data were analyzed using a mathematic approach, based on the hematocrit and blood volume where the percentual change in plasma volume was used to correct the values of each variable analyzed. Significance was inferred when P<0.05. The proposed mathematical model to assess blood constituents concentrations allowed the observation of a different pattern of the variables behavior, pointing out that the approach followed by the authors could be more sensitive than ones that did not take this routine. In conclusion, the method used in this study enabled to monitor the physiological processes that actually occur during endurance effort in tropical conditions.

Este estudo objetivou avaliar o comportamento dos componentes do sangue em cavalos que concluiram com êxito provas de enduro em condições tropicais. Punção da veia jugular foi realizada para coletar o sangue antes, durante e após o evento. Os dados foram analisados por meio de uma abordagem matemática, com base no hematócrito e volume de sangue onde a variação percentual no volume plasmático foi utilizada para corrigir os valores de cada variável analisada. O nível de significância adotado foi P<0,05. O modelo matemático proposto para avaliar as concentrações de componentes do sangue permitiu a observação de um padrão diferente no comportamento de várias variáveis plasmáticas, destacando que a abordagem seguida pelos autores é mais sensível do que aquelas que não seguiram este procedimento. Em conclusão, o método utilizado neste estudo permitiu acompanhar os processos fisiológicos que realmente ocorrem durante o esforço de resistência em condições tropicais.

Estabelecimento de índices ecocardiográficos de cavalos de polo / Establishment of echocardiographic index of polo ponies

The athletic training allows for morphologic and functional heart of horses undergoing different types of exercise, so studies have been published on the echocardiographic measurements of race horses, endurance horses and barrel horses, hunting horse, among others, otherwise, the echocardiographic indices of reference for polo ponies were not reported. Thus, echocardiographic measurements were performed in M-mode and 2D 20 polo horses in training, when they were divided into three age groups, namely: Group I consisted of eight animals aged between five and ten years, Group II with seven animals aged between 11 and 15 years, and Group III with five animals aged 16 to 22 years. The results of our study showed no statistical difference among different age groups, there was no standard yet for the values of correlations with weight, they are weak to strong, positive or negative.

O treinamento atlético permite uma adaptação morfológica e funcional do coração de cavalos submetidos a diferentes tipos de exercício, portanto já foram publicados estudos sobre mensurações ecocardiográficas de cavalos de corrida, cavalos de enduro, cavalos de laço e tambor, cavalos de caça, entre outros, de outra forma, os índices ecocardiográficos de referencia para cavalos de polo não foram relatados na literatura. Sendo assim, foram realizadas mensurações ecocardiográficas em modo-M e 2D de 20 cavalos de polo em treinamento, estando eles divididos em três grupos de faixa etária, ou seja: Grupo I que consistiu de oito animais com idades entre cinco e dez anos, Grupo II com sete animais com idades entre 11 e 15 anos, e o Grupo III com cinco animais com idades entre 16 e 22 anos. Os resultados do nosso estudo demonstraram que não houve diferença estatística entre os diferentes grupos de faixa etária, não foi observado ainda um padrão para os valores de correlações com o peso, sendo eles de fraco a forte, positivo ou negativo.

Effects of intravenous administration of caffeine on physiologic variables in exercising horses.

OBJECTIVE: To investigate the effect of acute administration of caffeine on the athletic performance of Arabian horses. ANIMALS: 12 healthy adult Arabian horses that were trained for exercise on a treadmill. PROCEDURES: By use of a crossover study design, horses received each of the following treatments: IV administration of caffeine (5 mg/kg) and IV administration of approximately the same volume of saline (0.9% NaCl) solution. Order of treatment was randomized, and there was a 10-day interval between treatments. Thirty minutes after treatments, horses underwent an incremental exercise test (IET) on a treadmill. Blood samples were collected 15 seconds before the end of each velocity step of the IET for determination of blood lactate, blood glucose, plasma cortisol, and plasma insulin concentrations. Heart rate and hematologic variables were also analyzed. RESULTS: Velocities achieved when heart rates were 180 and 200 beats/min increased significantly in caffeine-treated horses, compared with control horses. Velocities corresponding to blood lactate concentrations of 4 and 2 mmol/L decreased significantly in caffeine-treated horses, compared with control horses. In comparison between groups, insulinemia was greater in control horses and glycemia was greater in caffeine-treated horses. Plasma cortisol concentration was significantly lowered by treatment with caffeine. CONCLUSIONS AND CLINICAL RELEVANCE: IV administration of caffeine at 5 mg/kg improved the performance of Arabian horses during intense exercise of short duration and diminished the oxidative metabolism of glucose.