Canine parainfluenza type 2 and Bordetella bronchiseptica infection produces increased bronchoalveolar lavage thromboxane concentrations in beagle puppies

Acute infections in beagle puppies with canine parainfluenza virus type 2 (CPI2), and CPI2 in combination with Bordetella bronchiseptica (Bb) produce bronchiolitis and increased airways responsiveness to aerosolized histamine during the acute infection. In order to determine whether these observations were associated with increased levels of eicosanoids, the stable metabolites of thromboxane A₂ and prostacylin, thromboxane B₂ (TXB₂) and 6-keto-prostaglandin F_1α (6-keto-PGF_1α) respectively, and leukotriene B₄ were measured in the bronchoalveolar lavage (BAL) fluid of 25 beagle puppies (age = 76 ± 1 days, mean ± SEM) 3-4 days after no infection (control, n = 6), inoculation with both CPI2 and Bb (CPI2-Bb, n = 11), inoculation with CPI2 alone (CPI2, n = 4), and inoculation with Bb alone (Bb, n = 4). In addition, plasma levels of TXB₂ and 6-keto-PGF_1α were measured before and after infection in the CPI2-Bb and control groups. The BAL concentration of thromboxane B₂ was increased in the CPI2-Bb group (520 ± 120 pg/ml), but not in the CPI2 (88 ± 40 pg/ml), Bb (235 ± 100 pg/ml), or control groups (120 ± 60 pg/ml, p < 0.01). There also was a borderline increase in BAL concentration of LTB₄ in the CP12-Bb group. No differences were observed in the BAL concentration of 6-keto PGF_1α. Furthermore, neither TXB₂ nor PGF_1α was elevated in the plasma of control or CPI2-Bb puppies. These data suggest that increased thromboxane concentrations in BAL fluid are associated with histamine hyperresponsiveness during acute infection in the CPI2-Bb group.