Egypt. J. Zool., 70: 1- 12 (Dec, 2018) www.almanhal.com → e Journals → Science & Technical → Egypt. J. Zool., DOI: 10.12816/ejz.2018.26954 1 THE TOXIC EFFECT OF MULTI WALL CARBON NANOTUBES ON SWISS ALBINO RAT Safaa Gh. El-Sayed, Neamat H. Ahmed*, Kawkab A. Ahmed**, Aliaa M. Issa Zoology Department, Faculty of Science, Cairo University. *National Center for Radiation Research and Technology-Egyptian Atomic Authority. ** Pathology Department, Faculty of Veterinary Medicine, Cairo University. ABSTRACT Production and usage of multi-walled carbon nanotubes (MWCNTs) have widely increased over the last years. Nanoparticles with their sizes below 100 nm are able to enter and be stored in organs (such as liver, lung, testes and brain) and caused toxic effects. The aim of the present study is to investigate the MWCNTs toxicity, if any, on liver tissue. A total number of fifteen male albino rats were used in the present study; five rats as control and ten rats were intravenous injected with a single dose of MWCNTs (30 mg/ kg body weight, 20-50 nm in diameter and 1 μm in length). Histopatholgical, histochemical, apoptotic, necrotic and ultra-structure studies were carried out in the present work. The results showed different histopathological changes on liver tissues of MWCNTs-treated rats, such as focal hepatic necrosis with inflammatory cells infiltration, hydropic degeneration of hepatocytes, and some increases in collagen fibers deposition in the portal area after 28 days of MWCNTs injection. High appearance of necrotic and apoptotic cells was also noticed. Ultrastructure study of liver tissue of rats treated with MWCNTs showed abnormal hepatocytes with irregular nuclear envelope and nuclear chromatin material, swollen and fused mitochondria with destructed cristae, lysis of some cytoplasmic organelles and rupture of the endoplasmic reticulum. Shrunken nucleus and abundance of vacuoles and lysosome were also observed in the hepatocytes. It could be concluded that MWCNTs have a toxic effect on liver tissue and hepatocytes of rats. Keywords: Carbon nanotubes; Nanoparticles; Toxicity; Liver tissue. INTRODUCTION Nanoparticles (NPs) can be used in medicine for cancer treatment, infectious diseases, and diagnostic procedures with new imaging sensors and agent (Kagan et al., 2005; Shvedova et al.,2009). In general, the NPs have usually been made from transition metals, silicon, metal oxides, and different forms of carbon (carbon nanotubes and fullerenes). Inorganic NPs do not include carbon atom while carbon nanotubes and carbon fullerenes are titled as organic NPs (Ferreira et al., 2013). Carbon nanotubes (CNTs) have attracted much more industrial interest because of their unique properties (Kaiser et al., 2011). They could be manufactured as single- or multi- walled tubes. The majority of diameters of single-walled carbon nanotubes (SWCNTs ( are less than 10 nm, while those of multi-walled carbon nanotubes (MWCNTs) are generally above 20 nm up to 150 nm (Hou et al., 2003; Donaldson et al., 2006). CNTs have been used in biomedical engineering, tissue engineering, drug delivery, gene therapy, biosensors, cancer therapy, vaccine delivery, imaging and diagnostics (Spana et al., 2012). There are increasing probabilities for humans to contact CNTs as a result of their wide applications in the biomedical and material science field. Production and usage of MWCNTs have widely increased over the last years and nanoparticles with their sizes below 100 nm are able to enter and be stored in organs such as liver, lung, testes, and brain, causing toxic influences (Dan and Wan, 2016). The aim of the present study is to investigate the toxicity of MWCNTs on liver of male albino rats as being a vital organ as there is a scarcity of researches on this subject.