Final answer:
The matrix of dense regular connective tissue contains fibroblasts and fibrocytes as the main cell types.
Step-by-step explanation:
The matrix of dense regular connective tissue contains fibroblasts as the most abundant cell type. These fibroblasts secrete polysaccharides and proteins to produce a viscous ground substance that forms the extracellular matrix. Another less active form of fibroblast called fibrocytes is also present in connective tissue proper.