Introduction: Porphyromonas gingivalis, a Gram-negative anaerobic bacterium
found to be the major etiologic agent that contributes to periodontitis. It has been found
to be the major etiologic agent that contributes to periodontitis and produces many factors
that cause destruction to periodontal tissues in both ways directly and indirectly by
modulating the host inflammatory response. Silver nanoparticles are considered as an
effective antimicrobial agent and their ability to load various medication combinations
onto silver nanoparticles provides them a highly antibacterial mechanism of action,
to which bacteria have developed resistance. Aim: This study was designed to evaluate
the effect of silver nanoparticles loaded with tetracycline in treatment of induced
infection by Porphyromonas gingivalis of the rat's buccal mucosa through histological
examination and immunohistochemical localization of Proliferating Cell Nuclear
Antigen (PCNA). Material and Methods: Eighteen male albino rats were randomly
divided into three groups: normal (negative), infected (positive) with induced P. gingivalis
and treated group with nanosilver loaded with tetracycline for fourteen days.
Samples were examined under the light microscope for histological and immunohistochemical
evaluation through PCNA labeling index where the number of PCNA positive
cells were divided by the total cell number in the basal cell layer was estimated and
treated statistically. Results: Histological findings were represented by increase in the
surface epithelium, numbers of clear cells throughout different layers of epithelium
and great collagen dissociation at multiple areas in lamina propria of group II animals
while group III treated with nanosilver loaded with tetracycline showed epithelium regained
their normal histological structure with scattered inflammatory cells with almost
normal structure of lamina propria. There was significant decrease in PCNA labeling
index of the surface epithelium of the buccal mucosa of group II animals compared
with normal group I as well as significant increase in PCNA labeling index of group III.
Conclusion: Synergetic conjugation of nano-silver with antibiotic drug as tetracycline
showed improvement in the histological picture and cellular proliferation rate of epithelial
cells of rat's buccal mucosa.