Lead Organ and Tissue Toxicity: Roles of Mitigating Agents (Part 2)

Lead is a heavy metal which is reported to have toxicological effects on various organs in humans and animals. Due to its toxicological effects this study reviews current literature on the toxicological profile of lead on the testis, bone, blood and lungs and the possible roles of mitigating agents. In this study reports showed that in the brain lead induced cerebellar edema, cerebral satellitosis and encephalomalacia with impairments in cortex, hippocampus and cerebellum. Lead impairment of haematological parameters manifested as decrease in packed cell volume, haematoglobin, red blood cell count and total erythrocyte count. Anemia, leucopenia, neutropenia, lymphopenia and monocytopenia were also reported. Lead treated testis was characterized by reduction in the weight of sex glands, testicular sperm counts, daily sperm production, sperm density, sperm viability, sex hormones with increase in sperm abnormalities. Histopathological study of lead treated testis revealed loss of germ cells with pyknotic nuclei and vacuolated cytoplasm. Apoptosis of sertoli cells, leydig cells and mitochondria degeneration were reported. Lead treated lungs were characterized by mononuclear cell proliferation, mononuclear cell invasion, collagen fibre accumulation in the interalveolar septa and pneumonia. The antioxidants status of these organs were impaired making these organs vulnerable to lead induced oxidative stress. This laid credence to the generation of reactive oxygen species as one of the mechanisms of lead induced toxicological effects in various organs. In this study it was also observed that the toxicological effects of lead were mitigated by vitamin C, vitamin E, selenium, zinc and calcium. Chemical agents like melanin, casein, DMSA and CaNa2-EDTA also mitigated lead induced toxicity. Some extracts of plant origin also ameliorated the toxicological effects of lead. Some of these mitigating agents may require further evaluation if they could be of clinical application.