Chronic exposure to Lead and DNA, protein & ultrastructural changes in rat submandibular glands

Abstract

Objective: Structural changes of rat submandibular glands (SMG) after long-term treatment with lead were studied. Methods: After using various doses of lead (0.01%, 0.04%, 0.05%), SMGs were removed and homogenized for measurement of total protein, DNA, calcium and lead concentrations. Also ultrastructural examination of glands by electron microscopy (EM) was carried out. Findings: 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 rat’s 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 were also determined in the (0.04%) treated group. Conclusion: It is proposed 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 may ensue, including interaction with protein and DNA synthesis. To elucidate the exact mechanisms of observed alterations further studies are needed to conduct.

Keywords

• lead
• chronic exposure
• submandibular glands
• dna
• protein
• structural changes