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Immunological histopathology of American kestrels (Falco sparverius) exposed in ovo to two persistent organic pollutants -- SCCPs and TBBPA-BDBPE

February 23, 2021

This work is part of a study of the immunological effects of exposure to alternative flame retardants in avian species. For the pathology portion of the study, spleens and bursas from American kestrels (Falco sparverius) exposed by egg injection to varying doses of short-chain chlorinated paraffins (SCCPs) and the flame retardant TBBPA-BDBPE were examined microscopically for architectural and cellular abnormalities. At euthanasia, spleen and bursa of Fabricius were collected and fixed in 10% neutral buffered formalin for histopathological assessment. Slides were processed and stained with hematoxalin and eosin as per standard procedure (Luna 1968). Quantitative and qualitative B and T cell parameters were assessed by light microscopy. Specifically, variables assessed included the following: spleen: total area; number, thickness and area of peri-arteriolar lymphoid sheaths; number and diameter of lymphoid follicles; bursa: follicular and medullary area; cellular density; apoptosis; heterophil infiltration; presence of follicular cysts. Evaluation of the architecture and cellular population of immune organs will shed light on potential functional immunological effects of exposure that may lead to increased susceptibility to infectious disease or affect normal growth and development of the chick. (Luna LG. 1968. Manual of histologic staining methods of the armed forces institute of pathology, 3rd edn. McGraw-Hill, New York, NY.)