A macrophage hippocampal slice co-culture system: application to the studyof HIV-induced brain damage

We have developed an in vitro system that allows the study of the effects o f factors released from macrophages on neuronal and glial survival in cultu red hippocampal slices. Organotypic hippocampal slice cultures are grown on semi-permeable membranes in stationary co-culture with a murine macrophage cell line (RAW 264.7). The two culture systems are separated by a semi-per meable membrane specifically allowing the study of diffusable factors betwe en the two culture systems. The use of the fluorescent exclusion dye propid ium iodide as an in vitro marker of cell viability allows the study of prog ressive toxicity as it evolves in the slice cultures. We demonstrate that t he HIV-1 derived nuclear regulatory protein Tat induces toxicity in slice c ultures via the production of soluble mediators. The advantages of organoty pic cultures over other in vitro systems is discussed as well as the genera l applicability of this method to the study of other brain pathologies, whe n macrophage derived factors are thought to play a role in neuronal surviva l. (C) 1999 Elsevier Science B.V. All rights reserved.