Concomitant induction of apoptosis and expression of monocyte chemoattractant protein-1 in cultured rat luteal cells by nuclear factor-kappaB and oxidative stress.

It has previously been shown that expression of monocyte chemoattractant protein (mcp)-1 and apoptosis of luteal cells occur concomitantly during the estrous cycle in the rat corpus luteum; however, luteal cells containing mcp-1 mRNA did not seem to be apoptotic. In the present study, the relationship between the induction of apoptosis and mcp-1 expression in cultures of dispersed rat luteal cells was examined. Both apoptosis and mcp-1 expression were spontaneously induced in cultured luteal cells in a manner inhibitable by antioxidative reagents or an inhibitor of nuclear translocation of nuclear factor-kB. However, the cells containing mcp-1 mRNA were distinct from those undergoing apoptosis, and the inhibition of apoptosis by the pan-caspase inhibitor z-VAD-fmk did not influence the induction of mcp-1 expression. These results collectively indicate that oxidative stress simultaneously, but independently, induces apoptosis and mcp-1 expression in luteal cells through the activation of nuclear factor-kB. This phenomenon might help to explain how monocytes/macrophages accumulate in regressive corpora lutea where their target apoptotic cells exist.