Monocyte chemotactic protein-3: possible involvement in apical periodontitis chemotaxis

Aim To study the expression of monocyte chemotactic protein-3 (MCP-3, also known as chemokine CCL-7) in tissue from apical lesions (AL) and to associate MCP-3 expression with symptomatic or asymptomatic apical periodontitis. Methodology To determine the expression of MCP-3 in AL, biopsies obtained during tooth extraction procedures were fixed, subjected to routine processing and diagnosed as apical granuloma (AG) (n = 7) or radicular cyst (RC) (n = 5). As controls, apical periodontal ligament (PDL) specimens from healthy premolars extracted for orthodontics reasons were included (n = 7). All specimens were immunostained for MCP-3 and examined under a light microscope. In addition, homogenates from AL (n = 14) and healthy PDL samples (n = 7) were studied through immunowestern blot. Finally, periapical exudates samples were collected from root canals of teeth having diagnosis of symptomatic (n = 14) and asymptomatic apical periodontitis (n = 14) during routine endodontic treatments and analysed by immunowestern blot and densitometry. Results MCP-3 was detected in AG and RC and localized mainly to inflammatory leucocytes, whereas no expression was observed in healthy PDLs. MCP-3 was also detected in periapical exudate, and its levels were significantly higher in symptomatic than in asymptomatic apical periodontitis. Conclusions MCP-3 was expressed in AL and its levels associated with clinical symptoms. MCP-3 might play a role in disease pathogenesis, possibly by stimulating mononuclear chemotaxis.This study was supported by DI 07/02-2 and FONDECYT 1090461 funding. The authors express their gratitude to Leslie Henrı´quez for her excellent technical assistance, to Consuelo Fresno for her collaboration in sample collection, and to the Endodontic Society of Chile for its continuous support