Objective To observe dynamic distribution of 14C-benzo (a) pyrene14C-B(a)Pand the related damage of neuron in hippocampus of rat.
Methods A total of 150 Sprague Dawley rats were divided into control group and experimental group. The rats in the experimental group were given a single intravenous injection of 3.7& #215;105 Bq/kg of 14C-B(a)P while the same doses of normal saline were given to the control group. The rats were sacrificed at 1, 6, 12, 24 and 48 hours after the administration of radiolabelled 14C-B(a)P. Light microscopic autoradiography were used to observe the dynamic distribution of 14C-B(a)P in hippocampus tissue. The morphosis of neuron in the hippocampus of rats was observed by hematoxylin and eosin (HE)staining and a transmission electron microscopy.
Results The silver granules in the hippocampus of rats increased along with time, which reached the peak in 24h and sharply decreased in 48h. The silver grain counts were (22.31& #177;2.11)(, 23.11& #177;2.32)(, 25.97& #177;2.97), (28.16& #177;3.17)and (17.16& #177;1.85)grains/mm3 at 1, 6, 12, 24 and 48 hours after the administration of radiolabelled 14C-B(a)P, the difference was significant (F=28.65, P<0.01). The nucleus of neurons arranged in sparse and became smaller, and the number was also reducing, portion condensation phenomenon was recorded after 12 hours exposure to HE stain. The damage gradually in creased over time. Under transmission electron microscope, the damages of hippocampal neurons and organelles were varied at different time points after exposure, such as hippocampal nerve fiber edema, demyelination, swelling of mitochondria, golgi complex expansion, partial dissolution of the nuclear membrane and dense patches of presynaptic membrane.
Conclusion The silver granules in the hippocampus of rats increased along with time which reached the peak in 24 h. The damages of hippocampal neurons and organelles were varied at different time points.
DownLoad: