International Journal of Physical Sciences Vol. 2 (8), pp. 226-236, August, 2007 Available online at http://www.academicjournals.org/IJPS ISSN 1992 - 1950 © 2007 Academic Journals Full Length Research Paper Influence of electroporation on matrix metalloproteinases (MMPs) pattern activity in malignant glioma cells propagated ex vivo Monira M. Rageh 1* , Anwar A. Elsayed 1 , Amr A. Abd-Elghany 1 , Mohammed S. Mohammed 2 1 Department of Biophysics, Faculty of Science, Cairo University, Egypt. 2 Department of Cancer Biology, National Cancer Institute (NCI), Cairo University, Egypt. Accepted 18 June, 2007 Cells exposed to short and intense electric pulses become permeable to a number of various ionic molecules. This phenomenon was termed electroporation or electropermeabilization and is widely used for in vitro drug delivery into cells and gene transfection. The present work is a trial to study the effect of single exponential pulsed electric field (PEF) using intensity range 0.3 to 5.7 KV /cm and 1 m sec duration on human malignant glioma cells (U251MG). Under electrical conditions maintaining cell viability, no permeabilization can be detected for macromolecules such as DNA for pulse durations shorter than 1m sec. The aim of this study was to find optimum values of field strengths: First, to maintain cell viability for gene transfection and electrochemotherapy for further investigations. The above range of field strengths was used because a strong increase in the electric field intensity may increase transport of macromolecules, but as it may induce a loss in cell viability, indicated by the morphological observations in this study; it is associated with a decrease in plasmid expression. Second, to investigate the influence of PEF on metastatic biomolecules secreted in the cultured media such as matrix metalloproteinases (MMPs). MMPs enzyme activity was reduced at electric field intensities (0.3 - 1.15 KV/cm) by a factor of (25 - 100%). It is recommended to use the field intensity 0.85 KV/cm to put the glioma cells under biochemical stress during the electroporation protocol using single exponential pulse and 1 ms duration. Key words: Malignant glioma cells, electroporation, MMPs. INTRODUCTION Exposure of suspended cells to an exponentially decay- ing external electric field pulse of high intensity (kV/cm) and short duration (from 100 μs to several milliseconds) leads to a reversible electric breakdown of the membrane (Zimmermann et al., 1974). The breakdown of the mem- brane firstly is associated with a temporary increase of the membrane permeability. These permeability changes may be rapidly reversible or irreversible depending on the intensity and the width of the electrical pulses, as well as the composition of the suspending medium. After the rapid increase of the membrane permeability, many de- *Corresponding author. E-mail: monirarageh@yahoo.com. layed effects of the electrical stimulation were observed. These slower secondary effects included membrane fusions, membrane bleb formation, endocytotic reactions, and reorganization of the cytoskeletal network and in severe cases lysis of the cells. Global membrane rupture and cell death were mainly due to these secondary effects. Experiments showed that electrical stimulation introduced pores of limited sizes in the plasma mem- brane (Neumann et al., 1989). These pores could be resealed without losing the cytoplasmic macromolecular contents, and most cells survived after pore resealing. Electroporation possessed many applications in molecu- lar biology, genetic engineering, drug delivery, and bio- technology (Tsong, 1996). The exponential decay elec- troporators generally places considerable stress on the