Effect of Copper on the Body Wall Structures of the Medicinal Leech Hirudo Verbana Carena, 1820

Abstract

In this study, acute toxicity effects of copper on the fibroblast cells and body wall structures of medicinal leech (Hirudo verbana) were characterized by using light microscope and transmission electron microscope (TEM). For this purpose, live medicinal leech specimens were treated with 0.2 mg Cu(2+)/1 concentration for 96 hour. The samples were fixed in 2.5 % glutaraldehyde in 0.1 M phosphate buffer (pH=7.4) for electron microscopy study and post-fixed in 2.0% OsO(4) (4 degrees C). Samples were then fully dehydrated in the ethanol series and embedded in epoxy resin, which was polymerized for 48 h at 60 degrees C. Ultrathin sections were cut on Leica EM UC6 ultramicrotome and collected on copper grid (300 mesh). Semi-thin (approximately 700-800 nm) sections were put together, stained with toluidine blue, and analyzed. Thin sections (approximately 70-80 nm) were double stained with uranyl acetate, lead citrate and observed with FEI Tecnai transmission electron microscope. After 96h copper exposure, irregular and disorganized muscle fibres, degenerated epithelial cells and fibroblasts, decreased cuticular fold and body ondulas, and short and scattered microvilli were observed in treated medicinal leech.