Density and Intensity of Metallothionein in Gill and Interior Cavity of Taiwan Mussels (Anodonta woodiana) after Exposure to Lead (Pb) at Sub-Chronic Level using Immunohistochemical Technique

Abstract

Lead (Pb) is a heavy metal which is less useful and even toxic but at low concentration. Organisms respond to heavy metal stress with their distinctive defense system, such as the isolation, the compartmentalization, the complex building and the synthesis of adherent protein such as Metallothionein (MT) and Phytochelatins (PC). The increase of MT synthesis is related to the capacity building to bind the metal and to protect the binding from metal toxicity. The objective of research is to understand the density and intensity of MT expressed in the gill and interior cavity of Taiwan Mussels in various length sizes such 6, 8 and 10 cm after exposure to the lead at sub-chronic level. Research method is an experiment. Preliminary result showed that LC-50_{96 hours} of PbNO₃was obtained on Taiwan Mussels at dose 80.3 ppm. The result was used as the guide for sub-chronic level of exposure at various dosage(0 %, 12.5%, 25 %, 32.5 %, and 50 %) of LC-50_{96 hours} guidance dose. Research was conducted for 3 months. Sample was taken at 96 hours since the beginning of exposure.The coloring of sample preparation was by immunohistochemical technique, while the measurement of sample’s density and intensity was facilitated by Olympus SN 3K19322 Microscope and ImageJ program application. Result of research indicated that density and intensity of MT increase with the increasing of exposure dose. The increase of MT’s density and intensity was occurred at exposure of 30 ppm, but it was then decreasing at exposure of 40 ppm. Result of research also showed that the MT’s density and intensity averages in interior cavity were higher compared to the gill of Taiwan Mussels.

Keywords: lead, metallothionein,immunohistochemical