title: Effect of local nifedipine administration on rat gingiva.
abstract: BACKGROUND
  Nifedipine, a calcium channel-blocking agent, has been associated with gingival enlargement in humans. This enlargement has also been successfully established in animal models. Previous investigators have administered nifedipine through a systemic route, most commonly by oral intake. The aim of the present study was to measure the effects of nifedipine administered directly into rat gingival interproximal papillae.
  
  
  METHODS
  Twenty-four adult female rats were assigned to three groups. Each animal received a series of three injections, one week apart; each injection was placed directly into the interdental papilla of the maxillary and mandibular central incisors. Group 1 (control) received only saline. Group 2 received a low (10 microg/ml) concentration of nifedipine, while Group 3 received a higher concentration (500 microg/ml). One week after the last series of injections, gingival specimens were harvested from the injection site and prepared for histological and immunocytochemical analyses.
  
  
  RESULTS
  Specimens from Group 3 displayed a significantly greater number of ED2-positive cells compared to the other two groups. Specimens from Group 2 showed a significantly higher mean count of positive cells compared to Group 1. Collectively, our data suggest that repeated local injections of 10 microg/ml and 500 microg/ml nifedipine each elicit an inflammatory response in the gingival connective tissue.
  
  
  CONCLUSIONS
  Immunocytochemical analysis revealed dose-dependent increases of resident tissue macrophages in rats receiving nifedipine (p<0.005). An increased inflammatory infiltrate also was observed via routine histology. Gross macroscopic changes consistent with gingival enlargement were not observed.
authors.affiliation: School of Dental Medicine, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Bencivenni
authors.forename: Mirdza E
authors.initials: ME
authors.lastname: Neiders
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Andreana
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Moffitt
authors.forename: Robert E
authors.initials: RE
authors.lastname: Cohen
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000008:administration & dosage*; D002452:Cell Count; D003238:Connective Tissue / Q000187:drug effects / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004846:Epithelial Attachment / Q000187:drug effects / Q000473:pathology; D005109:Extracellular Matrix / Q000187:drug effects / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology; D005881:Gingiva / Q000187:drug effects* / Q000473:pathology; D005891:Gingivitis / Q000139:chemically induced / Q000473:pathology; D006098:Granulocytes / Q000187:drug effects / Q000473:pathology; D007150:Immunohistochemistry; D007180:Incisor; D007267:Injections; D007633:Keratins; D008214:Lymphocytes / Q000187:drug effects / Q000473:pathology; D008264:Macrophages / Q000187:drug effects / Q000473:pathology; D009543:Nifedipine / Q000008:administration & dosage*; D010586:Phagocytes / Q000187:drug effects / Q000473:pathology; D051381:Rats; D012965:Sodium Chloride; D013997:Time Factors
chemical_list: D002121:Calcium Channel Blockers; D012965:Sodium Chloride; D007633:Keratins; D009543:Nifedipine