Review on the Effect of Lead on the Histology of Brain and Lungs

Abstract

The physiological, biochemical, and behavioural dysfunctions of human beings and other animals are induced by lead. Its toxicity is mostly associated with age and sex of animals as well as duration and route of exposure, solubility, oxidation state, retention, frequency and, the absorption rate of lead. Lead and many other heavy metals mainly induce overproduction of ROS which in turn enhance lipid peroxidation, increase the unsaturated fatty acid content of the membranes and decrease the quantity of saturated fatty acid. ROS are by-products of many degenerative reactions in the tissues of many animals which affect regular metabolism by damaging the components of the cell. Overproduction of ROS in a variety of cells results in oxidative stress. Lead causes different disorders in human beings which can be in various forms such as cancer, nephrotoxicity, neurotoxicity and cardiovascular diseases. Oxidative stress is formed as a result of an imbalance between antioxidant defenses and production of free radical. Oxidative stress affects the content and molecular organization of lipids, proteins, and nucleic acids within the tissues. Superoxide radicals, hydrogen peroxide, hydroxyl radicals and LPO which are collectively known as a generation of ROS are known to damage various cellular components such as proteins, membrane lipids and nucleic acids. There are two separate pathways where Lead toxicity leads to free radical damage. These are: (1) the generation of ROS namely hydroperoxides (singlet oxygen), and hydrogen peroxides. (2) direct reduction of antioxidant reserves. The toxicity of lead is the result of its ability to act as a nonspecific enzyme inhibitor due to its high affinity for sulfhydryl residues in proteins. In addition, lead also exerts toxic effects because of its ability to combine with oxygen and sulfur-containing bioligands. Lead has toxic influences on the various organs of human beings and other animals such as in the brain, lungs kidneys, liver, bones, heart and other organs of the body. The aim of this review is to give a comprehensive report of the existing data on the adverse effects of lead on brain and, lung toxicity by histological study and biochemical assay of brain and lung enzyme levels.

Keywords: Brain, hydroperoxides, lead, lung, reactive oxygen species

Cite this Article: Nigus Abrha Tafere. Review on the Effect of Lead on the Histology of Brain and Lungs. International Journal of Biomedical Engineering. 2019; 5(2): 30–56p.