Abstract

COMPARATIVE ANALYSIS OF CYCLOPHOSPHAMIDE MONOHYDRATE CLASTOGENICITY AND MUTAGENICITY IN HEALTHY HUMAN LYMPHOCYTES AND L5178Y TK+/- MOUSE LYMPHOMA CELLS

Pasula Chandra Sekhar*, Tadakaluru Yasodha Lakshmi, Sannidhi Ranga Suresh, Pujari Venkata Suresh Reddy, Chirumamilla Venkata Satish Kumar, Raja Ratna Reddy Yekkanti

Aptus Biosciences Pvt. Ltd, SVS Medical College,  Mahabubnagar, Andhra Pradesh, India.

ABSTRACT

The study was conducted to evaluate and compare the clastogenicity and mutagenicity of cyclophosphamide monohydrate in In vitro Mammalian Chromosome Aberration Test (CAT) using cultured healthy human whole blood lymphocytes and In vitro Cell Gene Mutation Assay (CGM) using L5178Y TK+/- mouse lymphoma cells as per OECD guidelines No. 473 & 476 respectively [1,2], both in the presence (2%v/v) and absence of metabolic activation system. Cyclophosphamide monohydrate is mutagenic at the doses 1.95, 3.90, 7.81, 15.62 μg/ml in CGM and 15.62, 31.25, 62.5 μg/ml in CAT. Mutagenicity was observed only in the presence of metabolic activation system in both CGM and CAT. Cyclophosphamide monohydrates require metabolic activation for its mutagenicity in both the tests. A lower dose of cyclophosphamide monohydrate is mutagenic in CGM than CAT. Based on the positive response of cyclophosphamide monohydrate in both Assays, colony sizing was performed in CGM, dose dependent increase in the small size colonies were observed. Mutant cells that have suffered the most extensive genetic damage have prolonged doubling times and thus form small colonies. This damage typically ranges in scale from the losses of the entire gene to karyotypically visible chromosome aberrations. Small colony number data from CGM may provide clastogenicity details of test drug and provide the basis for the comparison, results correlation in CGM and CAT. Small colony number data of CGM may also provide the range of dose for CAT, before study conduct and provide scientific justification for step wise study selection to evaluate the genotoxicity of test drug.

Keywords: Cyclophosphamide monohydrate, mutagenicity, clastogen, metabolic activation, aberration, small colony.