Dear Saba,

You can try many methods like EZBlue or BrDu but people have used BrDu convincingly in case of HUVEC so I will suggest to try that.. PFA link..

http://www.fasebj.org/content/20/12/2027.full

Hope it helps!

Dear Saba,

You can try CFSE assay. You can observe each cellular division separately. This method is applicable for both in vitro and in vivo studies.

http://www.ncbi.nlm.nih.gov/pubmed/15057261

Thanks everyone

Dear Saba,

I would also suggest VPD450 from BD, easy technique for flow cytometry,