Objective: To study the toxicity of lead poisoning to submandibular gland and its effects on nerve growth factor (NGF) gene expression in mice.
Methods: An experimental model with lead poisoning was established and its histopathological changes in the submandibular gland of mice were observed under light and electronic microscopes. Effects of lead poisoning on expression of NGF mRNA in submandibular gland were analyzed quantitatively by human NGF DNA probe labelled with digoxin with in situ hybridization.
Results: Body weight of the mice with experimental lead poisoning reduced, and their lead levels in blood and submandibular gland increased. Lobular atrophy, fibrous hypertrophy, angiectasis of the stroma and enlargement of lobule interstitial in mouse submandibular gland with lead poisoning could be found under light and electron microscopes. Their rough surfaced endoplasmic reticulum was extended and mitochondrion swollen. Graphic analysis showed that diameters of the secretory striate ducts and granular tubules decreased in the mice with lead poisoning. Results of in situ hybridization indicated that hybridized signals in the granular and secretory striate ducts and granular tubules reduced significantly, and NGF mRNA expression decreased.
Conclusion: Lead is toxic to the submandibular gland of mice and can affect their NGF gene expression.