RESUMEN
Petroleum oil enters the coastal marine environment through various sources; marine mammals such as sea otters that inhabit this environment may be exposed to low concentrations of petroleum hydrocarbons through ingestion of contaminated prey. The inability to perform controlled studies in free-ranging animals hinders investigations of the effects of chronic petroleum oil exposure on sea otter morbidity and mortality, necessitating the development of a reliable laboratory model. We examined the effects of oral exposure to 500 ppm bunker C fuel oil over 113-118 days on American mink, a species phylogenetically related to the sea otter. Hematological parameters and organs were examined for fuel oil-associated changes. Hepatic cytochrome P4501A1 mRNA expression and fecal cortisol concentrations were also measured. Ingestion of fuel oil was associated with a decrease in erythrocyte count, hemoglobin concentration (Hgb), hematocrit (HCT), and an increase in mean corpuscular volume (MCV). Total leukocytes were elevated in the fuel oil group from increases in neutrophils, lymphocytes, and monocytes. Significant interactions between fuel oil and antigen challenge were found for erythrocyte parameters, monocyte and lymphocyte counts. Liver and adrenal weights were increased although mesenteric lymph node weights were decreased in the fuel oil group. Hepatic cytochrome P4501A1 mRNA was elevated in the fuel oil group. Fecal cortisol concentration did not vary between the two groups. Our findings show that fuel oil exposure alters circulating leukocyte numbers, erythrocyte homeostasis, hepatic metabolism and adrenal physiology and establish a framework to use mink as a model for sea otters in studying the systemic effects of marine contaminants.
Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas , Aceites Combustibles/toxicidad , Visón/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Citocromo P-450 CYP1A1/biosíntesis , Citocromo P-450 CYP1A1/genética , Dinitrobencenos/metabolismo , Recuento de Eritrocitos , Heces/química , Hemoglobinas/metabolismo , Histocitoquímica , Hidrocortisona/metabolismo , Recuento de Leucocitos , Hepatopatías/sangre , Hepatopatías/metabolismo , Masculino , Visón/sangre , Modelos Animales , Tamaño de los Órganos/efectos de los fármacos , Nutrias/sangre , Nutrias/metabolismo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Distribución Aleatoria , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
A 6-month-old Holstein heifer that was nonresponsive to medical treatment was evaluated for chronic respiratory disease. Complete blood count and serum chemistry revealed neutrophilic leukocytosis and low globulin levels. Assays for bovine leukemia virus, bovine virus diarrhea, and bovine leukocyte adhesion deficiency were negative. Serum globulin subclass assays revealed transient low concentrations of immunoglobulin (Ig) G1 and IgA, persistent low IgG2, and subnormal IgM. Vaccination with 2 doses of multiple, inactived viruses induced seroconversion for most viruses. Flow cytometric analysis of blood lymphocyte subpopulation demonstrated an increase in CD5+ B-cells. Blood lymphocyte proliferation and neutrophil function tests were normal. Results of immunologic assays indicated IgG2 deficiency with transient hypogammaglobulinemia.
Asunto(s)
Agammaglobulinemia/inmunología , Agammaglobulinemia/veterinaria , Bronconeumonía/inmunología , Bronconeumonía/veterinaria , Enfermedades de los Bovinos/inmunología , Deficiencia de IgG/veterinaria , Animales , Linfocitos B/citología , Linfocitos B/inmunología , Antígenos CD5/inmunología , Bovinos , Proliferación Celular , Resultado Fatal , Femenino , Deficiencia de IgG/inmunología , Inmunoglobulina G/inmunologíaRESUMEN
The relationship between exposure to environmental contaminants and immunotoxicity in vulnerable marine species is unknown. In this study, we used American mink (Mustela vision) as a surrogate species for the sea otter to examine the immunotoxic effects of chronic exposure to a low concentration of bunker C fuel oil (500 ppm admixed in the feed for 113-118 days). The mink immune system was monitored over time by flow cytometric analysis for alterations in the immunophenotype of blood lymphocytes and monocytes and by mitogen-stimulated proliferation assays for changes in peripheral blood mononuclear cell function. Fuel oil exposure caused a mild, yet significant (P < 0.05) increase in the absolute numbers of specific peripheral blood lymphocyte subsets (CD3+T cells) and monocytes, an increase in the level of expression of functionally significant cell surface proteins (MHC II, CD18), and an increase in mitogen-induced mononuclear cell proliferative responses. This heightened state of cellular activation along with the increase in specific cell surface protein expression on both the innate and adaptive immune cells is similar to the pro-inflammatory or "adjuvant-like" effect described in laboratory models of polycyclic aromatic hydrocarbon exposure in other species. These results show the benefits of using a controlled laboratory model for detecting and characterizing subtle petroleum oil-induced perturbations in immune responses. In addition this study establishes a framework for studying the effects of environmental petroleum oil exposure on the immune system of free-ranging marine mammals. Expansion of these studies to address biolgical significance is warranted.