Effects of cytomegalovirus infection on the mRNA expression of collagens and matrix metalloproteinases in gingival fibroblasts

The purpose of this in vitro investigation was to study the effects of human cytomegalovirus infection on the mRNA expression for collagens I and III and for matrix metalloproteinases 1 and 2 in gingival fibroblasts. Gingival fibroblasts were experimentally infected with the Towne strain of human cytomegalovirus and the kinetics of expression of mRNA for collagens I and III and for matrix metalloproteinases 1 and 2 was studied at different time-points. Total RNA was isolated at the indicated time, and the reverse transcription-polymerase chain reaction was used to analyze the level of mRNA expression. In addition, gingival specimens were obtained from 14 periodontitis and from three non-periodontitis subjects and mRNA analysis for collagens and metalloproteinases was carried out. Nested polymerase chain reaction was used to determine the presence or absence of human cytomegalovirus in subgingival samples from each subject. The infection of gingival fibroblasts with human cytomegalovirus during a 0-72-h period resulted in progressive reduction in the expression of mRNA for collagens I and III (p < 0.05). A higher concentration of human cytomegalovirus resulted in varying degrees of mRNA reduction, suggesting a virally mediated effect. Biopsies from human cytomegalovirus-positive individuals with periodontitis had a higher expression of mRNA for collagens I and III than biopsies from human cytomegalovirus-negative individuals. An up-regulation in the mRNA expression of matrix metalloproteinases 1 and 2 over time was observed (p < 0.05). Analysis of mRNA expression in gingival biopsies demonstrated higher expression of matrix metalloproteinase-1 in human cytomegalovirus-positive periodontitis specimens compared with human cytomegalovirus-negative periodontitis specimens. Altered expression of mRNA for collagens and metalloproteinases in human cytomegalovirus-infected gingival fibroblasts should be considered as possible modifying mechanisms in periodontitis-infected sites.