Human smooth muscle cells (SMCs) usually show staining for contractile alpha-actin and desmin filaments in their cytoplasm; fibroblasts do not stain for these.

Also, confluent SMCs appear aligned in parallel so that the broad nuclear region of a cell lies adjacent to the thin cytoplasmic area of another, forming a 'hill-and-valley' appearance.

Thank You Marisa, that help me much!

I have a homogenous population, but I'm not sure which cell tipe. After confluency of the cells, they have no contact limitation of the prolferation and overgrowth each other.

I will try the staining.

Thanks!