Expression and localization of human kallistatin in rat submandibular gland after intracapsular gene injection

Gene delivery into rat submandibular gland in vivo by direct intracapsular injection has been studied. After the administration of adenovirus constructs, Ad-RSV-LacZ and Ad-CMV-LacZ, beta-galactosidase expression was localized in the granular convoluted tubular and striated duct cells of rat submandibular gland by in situ enzyme histochemistry. Adenovirus-mediated delivery of the human kallistatin gene (Ad-RSV-HKBP) into rat submandibular gland results in the expression of human kallistatin in a time-dependent manner. The expression of immunoreactive kallistatin in submandibular gland was detected 1 day after the Ad-RSV-HKBP injection and it reached a plateau (1-2 ng/mg protein) 2 days after gene delivery. Higher levels of human kallistatin were found in the submandibular gland of 6-month-old rats than in one-month-old rats. After direct gene injection, human kallistatin was localized mainly in cells of the granular convoluted tubules and striated ducts of rat submandibular gland using a specific monoclonal antibody to human kallistatin. The results indicate that direct intracapsular gene delivery into the submandibular gland provides a simple and reliable method for introducing foreign genes into the gland. This method can be used for studying gene regulation in vivo and may have potential for gene therapy in oral diseases.