In-vivo Anti-tumor Evaluation of Dihydroartemisinin-Derived Endodisulphide on MNU-induced Liver Cancer in Sprague-Dawley Rats
Imoh Emmanuel Udoh
Department of Clinical Pharmacy and Biopharmacy, Faculty of Pharmacy, University of Uyo, Uyo, Nigeria.
Jonah Sydney Aprioku *
Department of Experimental Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of Port Harcourt, Port Harcourt, Nigeria.
Iyeopu Minakiri Siminialayi
Department of Pharmacology, Faculty of Basic Medical Sciences, University of Port Harcourt, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: The study evaluated the antitumor potentials of a disulphide-substituted derivative of dihydroartemisinin (sDHA) on chemically induced cancer of the liver in Sprague-Dawley rats in comparison with its parent compound, dihydroartemisinin (DHA) and a standard anticancer drug.
Study Design: Animals were divided into seven experimental and three control groups (n=10 per group). Cancer was induced in experimental groups followed by administration of experimental agents, while control groups received either N-methy-N-nitrosourea (MNU), Tween 80 (vehicle) or distilled water alone.
Place and Duration of Study: Study was done in Faculty of Pharmacy, University of Uyo, Nigeria in 2015-2016.
Methodology: MNU (50 mg/kg) was administered intravenously as single dose to induce cancer in experimental groups, followed by oral treatment with sDHA (37.42, 74.83 or 112.25 mg/kg/day), DHA (57.45, 114.89 or 172.34 mg/kg/day) or cyclophosphamide (0.71 mg/kg/day) for 28 days. Positive control group received only MNU, negative control group received only distilled water (0.3 ml/day), while experimental control group received only Tween 30 (0.3 ml/day). Drug treatments commenced 10 days after MNU injection and animals were observed for 52 days after drug treatments and sacrificed. Serum levels of CA-27-29, 8-OHdG and SOD were measured using ELISA method; and using immunohistochemical tissue staining techniques, Bcl-2 and Ki67 protein expressions were analyzed in hepatic cells.
Results: MNU caused elevation (P <.0001) in CA-27-29 and 8-OHdG; and reduction (P<.0001) in SOD. Hepatic cells of MNU alone treated rats demonstrated strong immunoreactivity for Bcl-2 and Ki67 (≥75%). Oral treatments of sDHA or DHA resulted in dose-dependent reductions of MNU-induced CA-27-29 and 8-OHdG elevations (P<.001) but had no effect on SOD. Additionally, MNU induced Bcl-2 and Ki67 positive immunoreactive expressions were reduced to 25-50% by sDHA and DHA; DHA showing greater effect. Cyclophosphamide reversed all the MNU induced toxic effects.
Conclusions: sDHA possesses antitumor activity against liver cancer; has lesser efficacy than DHA, but both drugs are less effective than cyclophosphamide.
Keywords: Artemisinin, Bcl-2, CA-27-29, cyclophosphamide, immunohistochemistry