PARENT SESSION
PT2 - Endocrine Disruption
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P568) Altered Testis Development in Chicken Embryos (Gallus domesticus) Exposed to Aroclor 1254.
Grasman, Keith1, Reaves, M. Elissa*,1, 1 Wright State University, Dayton, OH, USA
ABSTRACT- PCBs (polychlorinated biphenyls) were released into the environment as commercial mixtures and are now found in wildlife tissues around the world, including fish-eating birds of the Great Lakes. At some sites, Great Lakes birds have had altered reproductive behavior and development since the 1970s. Testicular nodules and ovotestes have been documented in fish-eating seabirds. However, the question remains whether PCBs or PCB mixtures can alter the organization and development of the avian reproductive system. To determine whether Aroclor 1254, a commercial PCB mixture, disrupts gonadal development, white leghorn chicken eggs were injected with varying doses of Aroclor 1254 (5, 50, 500, 5000 ng/g egg) on day 0 of incubation. Reproductive tracts were examined on day 20 of incubation. Gonads were fixed in formalin, embedded in Spurrs epoxy, sectioned, and stained with toluidine blue for histological examination. Body mass was similar among treatment groups and between sexes. Histological analyses revealed structural abnormalities of the testes. Seminiferous tubules extending through the cortex occurred at 11% in controls, with increased rates of 30%, 25%, and 22% at Aroclor doses of 5, 500, and 5,000, respectively. Nodules, residual primordial germ cells in the cortex, were only observed in the lowest Aroclor dose (10%). Quantitative histological endpoints, such as Sertoli density and medulla area, were similar among treatments. Within females, ovary mass index was similar among treatments. No differences were detected in any histological measurements of the ovary. Aroclor caused some structural alterations of the testis but did not reproduce many abnormalities (ovotestis, nodules, reduced Sertoli density) seen in herring gull embryos and chicks at polluted Great Lakes sites.
Key words: chicken, Aroclor 1254, endocrine disruption, histology