Figure 4. Immunreactivity of MMP-2 protein in major salivary gland, 40X. A) Parotid gland of young mice; B) Parotid gland of old mice; C) Sublingual gland of young mice; D) Sublingual gland of old mice; E) Submandibular gland of young mice; F) Submandibular gland of old mice; *Yellow arrow: Stained cell nuclei.