| dc.description.abstract | Resumo: A doenca inflamatoria das vias aereas (DIVA) e a hemorragia pulmonar induzida pelo exercicio (HPIE) sao comuns em cavalos de corrida, resultando em interrupcao no treinamento. A hipotese do presente estudo foi de que o ambiente e o exercicio causam estresse oxidativo, producao do fator de ativacao plaquetaria (PAF) e inflamacao nas vias aereas de potros PSI de corrida, e que ha uma relacao entre a DIVA e a HPIE. Estudou-se potros PSI em ambiente natural (NC, n=45), estabulados por 30 dias (DA, n=40) e treinados (EX, n=34). Apos, os potros do grupo EX foram divididos em tres subgrupos: HPIE pos (presenca de hemossiderofagos no lavado broncoalveolar - LBA), HPIE neg (ausencia de hemossiderofagos no LBA) e EX normal (ausencia de hemossiderofagos no LBA e menos de 5% de neutrofilos e menos de 1% de eosinofilos no LBA). Avaliou-se perfil citologico e parametros do LBA relacionados a estresse oxidativo, bioatividade de PAF, atividade da catalase e funcao de macrofago alveolar (MA). Os percentuais de neutrofilos e eosinofilos no LBA do grupo EX foram maiores (5,4 }1,1% vs. 0,9 }0,2% P<0,001 e 1,5 }0,7 vs. 1,2 }0,1 P<0,05, respectivamente) que os limites superiores para cavalos normais (5% para neutrofilos e 1% para eosinofilos), juntamente com um maior numero total de celulas nucleadas (45,6 }2,8 vs. 34,3 } 2,4 celulas/ƒÊL de LBA P=0,017), evidenciaram a ocorrencia de inflamacao pulmonar. A bioatividade de PAF e a concentracao de proteinas no LBA foram maiores no grupo EX (relacao 340:380 nm 0,068 } 0,02 vs. 0,006 } 0,002 P=0.017, 0,36 } 0,06 vs. 0,14 } 0,03 mg de proteinas/mL de LBA P<0,001). A concentracao de hidroperoxidos no LBA foi maior no grupo DA (104,7 } 24,1 vs. 35,2 } 8,4 nmoles/mg de proteinas, P<0,001) e a atividade da catalase foi maior no grupo EX (0,24 } 0,05 vs. 0,06 } 0,01 ƒÊmol H2O2/min/mg de proteinas, P=0,002). A fagocitose de MA (P=0,006) bem como a producao de anion superoxido (P<0,001) e peroxido de hidrogenio (P=0,006) foram significativamente menores no grupo EX. Vinte e tres (62,2%) potros do grupo EX foram HPIE pos, e o LBA desse subgrupo apresentou concentracao de proteinas (0,39 } 0,08 vs. 0,19 } 0,04 mg de proteinas/mL de LBA, P=0,031), bioatividade de PAF (relacao 340:380 nm 0,180 } 0,05 vs. 0,043 } 0,02, P=0,042) e concentracao de hidroperoxidos lipidicos (36,7 } 9,3 vs. 6,2 } 2,0 nmoles /mg de proteinas, P=0,009), significativamente maiores que o subgrupo HPIE neg. A concentracao de nitritos (0,08 } 0,03 vs. 0,12 } 0,07 absorbancia 550 nm, P=0,049) e a atividade de MA foi menor em comparacao com o subgrupo HPIE neg. O ambiente e o exercicio modificaram o fluido broncoalveolar, confirmando a hipotese do presente estudo. Houve aumento da resposta de MA induzida pelo ambiente, enquanto o exercicio fisico resultou em HPIE, inflamacao pulmonar e diminuicao na resposta imune inata relacionada aos macrofagos alveolares, nos potros PSI jovens durante o treinamento para corrida, e o PAF esteve presente nesse processo. Sugere-se a conducao de novas investigacoes para elucidar os mecanismos inflamatorios da HPIE, bem como o papel do PAF neste processo, como um potencial alvo terapeutico. | pt_BR |
| dc.description.abstract | Abstract: Inflammatory airway disease (IAD) and exercise-induced pulmonary hemorrhage (EIPH) are common in racehorses during training, being important ailments interrupting training of thoroughbred racehorses. The present study hypothesis was that stabling and exercise cause oxidative stress, release of platelet-activating factor (PAF) and inflammation in airways of Thoroughbred colts, and that there is an association between IAD and EIPH. The subjects were colts in breeding farms (NC, n=45), stabled for 30 days (EC, n=40) and race trained (EX, n=34). Colts of the EX group were subdivided into three subgroups: EIPH pos (presence of hemosiderophages in BALF), EIPH neg (absence of hemosiderophages in BALF) and Normal EX (absence of hemosiderophages and less than 5% neutrophils and 1% eosinophils in BALF). Cytological profile and parameters of bronchoalveolar lavage fluid (BALF) related to oxidative stress, bioactivity of the pro-inflammatory mediator PAF, catalase activity, and alveolar macrophage (AM) activity were studied. Percentages of neutrophils and eosinophils in the BALF of the EX group were higher (5.4 ±1.1% vs. 0.9 ±0.2% P<0.001 and 1.5 ±0.7 vs. 1.2 ±0.1 P<0.05, respectively) than the upper limits for normal horses (5% of neutrophils and 1% of eosinophils), that associated with a significantly higher total nucleated cell count (45.6 ±2.8 vs. 34.3 ± 2.4 cells/ìL of BALF P=0.017), displayed pulmonary inflammation. PAF bioactivity and the total protein concentration in the BALF were higher in the EX group (0.068 ± 0.02 vs. 0.006 ± 0.002 340:380nm ratio P=0.017, 0.36 ± 0.06 vs. 0.14 ± 0.03 mg of proteins/mL of BALF P<0.001). Concentration of BALF hydroperoxides was higher in the EC group (104.7 ± 24.1 vs. 35.2 ± 8.4 nmoles/mg of proteins P<0.001) and catalase activity was higher in the EX group (0.24 ± 0.05 vs. 0.06 ± 0.01 ìmol H2O2/min/mg of proteins P=0.002). AM phagocytosis (P=0.006) as well as production of superoxide anion (P<0.001) and hydrogen peroxide (P=0.006) were significantly lower in EX group. Twenty three (62.2%) colts of the EX group were EIPH pos, and the BALF of this subgroup presented a significantly higher protein concentration (0.39 ± 0.08 vs. 0.19 ± 0.04 mg of proteins/mL of BALF P=0.031), PAF bioactivity (0.18 ± 0.05 vs. 0.043 ± 0.02 340:380 nm ratio P=0.042) and lipid hydroperoxide concentration (36.7 ± 9.3 vs. 6.2 ± 2.0 nmoles / mg of proteins P=0.009), as well as lower nitrite concentration (0.08 ± 0.03 vs. 0.12 ± 0.07 absorbance 550 nm P=0.049) and AM activity than EIPH neg subgroup. Environment and exercise modified the bronchoalveolar fluid, confirming the hypothesis of the present study. Environment increased AM response, as exercise resulted in EIPH, pulmonary inflammation and decreased innate immune response of alveolar macrophages, in young Thoroughbred horses during race training, and PAF participated in this event. Further studies should be conducted to better understand the inflammatory mechanisms of EIPH, and the role of PAF in this process, as a potential therapeutic target. | pt_BR |
