Abstract

EVALUATION OF METALLOTHIONEINS IN THE CULTURED HUMAN LYMPHOCYTES ON EXPOSURE TO SILVER IONS

K. V. Shalini* and G. P. Jeyanthi

ABSTRACT

Silver (Ag) is a non - vital metal used in a wide variety of applications. Since the time of its wide spread uses, the systems participation in the uptake of silver in the human cells was poorly known. Animal and cell culture studies showed that silver exposure may lead to reduced cell proliferation and impaired immune function. Silver exposure occurs to human through occupational settings or from consumption of Ag-containing medicines which can result in deposition of significant amounts of Ag in the eyes, skin and other tissues. However, it is very difficult to determine the potential toxicity of silver, because its bioavailability is dependent on the physical, geochemical and biological processes that determine metal uptake by living organisms. This ionized silver is removed by the enzymic and non – enzymic antioxidant defense systems. Metallothioneins (MTs) belong to the group of intracellular, cysteine rich, non enzymic antioxidants and are closely related to stress response proteins which are involved in detoxification processes of heavy metals. Therefore it is a candidate for an index in the biological monitoring of heavy metal exposure. To date, information about the toxicity of silver compounds still has not been clarified. To evaluate this, in vitro experiments were designed such that the human PBLs were exposed to AgNO3 to represent the exposure to Ag+ ions to cells and also to better understand the role of MT in metal stress.

Keywords: Silver Nitrate, Metallothioneins, Peripheral Blood Lymphocytes.