Influence of experimental neutropenia in dogs with chronic gingivitis

The influence of a four day period of experimental neutropenia on the clinical state and the structural constituents of chronically inflamed gingiva has been studied in four beagle dogs. Neutropenia was induced by heterologous anti-neutrophil serum. The effects on the gingiva were evaluated by Gingival Index (GI) and Gingival Exudate measurements and by morphometric analysis of various tissue components in sections from biopsies of buccal gingiva sampled on days 2, 3, and 4. Control biopsies were obtained before induction of neutropenia. The GI did not markedly change during the observation period. The amount of Gingival Exudate, however, significantly decreased following the induction of neutropenia and remained low throughout the experiment. Neutrophilic granulocytes disappeared in the gingival tissues, while, apart from a relative increase in plasma cells, no other tissue components seemed to change. No bacterial invasion of the junctional epithelium or of the gingival connective tissue could be observed. Thus during a four day period the bacterial defense mechanisms at the dentogingival junction seem to be able to prevent penetration of microorganisms into the gingival tissues despite the absence of neutrophilic granulocytes.