Abstract
Structural changes of rat submandibular glands (SMG) after long-term treatment with various doses of lead (0.01%, 0.04%, 0.05%) were investigated in this study. After termination of treatment, SMGs were removed and homogenized for measurement of total protein, DNA, calcium, and lead concentrations. Also ultrastructural examination of glands by electron microscopy was carried out. Total protein, DNA, and intracellular calcium concentrations of treated glands at 0.04% and 0.05% lead concentrations showed significant reduction when compared with those of controls. Data of lead measurement, as determined by atomic absorption spectroscopy, showed that lead treatment resulted in accumulation of lead in rats'SMGs. Lead treatment also caused degenerative changes in the cells. Dilation of rough endoplasmic reticulum (RER) and swollen mitochondria were observed in the (0.05%) treated group. Transformation and enlargement of mitochondria also were determined in the (0.04%) treated group. We propose that lead treatment can reduce exocytosis processes by the reduction in energy level of the cell and destruction of RER or mitochondria. Considering properties of lead to substitute for calcium in many intracellular events, different types of alterations can result, including interaction with protein and DNA synthesis. To elucidate the exact mechanisms of observed alterations requires further studies.
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