You can use serum with media to do Gelatinase zymography. Regardless, you will need to concentrate the media before loading onto a gel. You can use serum free media but the cells won't be happy after 24hrs.

Serum too contains mmps. Won't this cause difficulty in interpretation of my results. I am studying cardiac remodeling and here mmps ( 2 & 9) are important for extracellular matrix degradtion.

The amount from fibroblasts will be much higher. One normally looks at media with serum as a control or to look at background levels. If you want to use media without serum, you can. The cells will be ok for a day or two. I will try to find the conditions we used and give them to you. I think we used insulin in the media when we serum starved the cells. But we only used 24 hr.

For preparing serum Fred media u just have to plate cells at high density in normal complete media and allow the cells to grow till conflyebcy. Once the cells are almost confluent you can replace the complete media with  media whout serum Nd this serum free condition can be used for preparing condition media, testing reagents or running zymogarm 

I agree with Anil and Marcia.  The only suggestion I have is maybe use fatty acid and protease free BSA to your serum-free media if insulin doesn't keep them happy enough.