Resumo

Candida is the most prevalent yeast in apical periodontitis. Characteristics as thigmotropism, production of hydrolytic enzymes, ability to adhere to substrates, biofilm and pleomorphism are primary contributors for Candida colonization of tooth environment. Proteolytic activity of C. albicans is associated with a family of 10 aspartic isoenzymes encoded by 10 different genes. Because lack of knowledge of yeast associated dental disease, characterization of Candida isolates from oral sites is very important to determine the etiology of the disease. Therefore this work aimed to investigate proteinase secretion in serum albumin medium in 104 C. albicans strains isolated from two oral sites, 70 strains were obtained from lingual dorsum and 34 from necrotic root canals. Aspartyl proteinases transcripts encoded by three genes (SAP-1, SAP-2 and SAP-4) were accessed by RT-PCR. All investigated strains were able to hydrolase bovine serum albumin, however only 55.7% strains of lingual dorsum exhibited high proteinase activity; on the other hand 100% of strains from necrotic root canals displayed high enzymatic activity. Thus, the evidence of increased proteolytic activity of the isolates of root canals suggests a pathogenic potential that may favor the strains in endodontic environment. Detection of RNA transcripts revealed different patterns of expression SAP genes among strains. In root canals C. albicans strains only SAP-4 transcripts were identified in 100% of strains, SAP-1 and SAP-2 transcripts appeared in 29.4% and 85.3%, respectively. Different data were obtained from lingual dorsum strains; SAP-1 was expressed by 67.1% and SAP-4 by 87.1%. SAP-2 transcripts had similar frequency of strains of root canals. Results showed that expression of SAP-1 may not be necessary for colonization and maintenance of endodontic infection being the enzyme Sap-4 the one required to colonize the inner layer of dentin and perpetuate the infection. Simultaneous expression of three investigated SAP genes (SAP-1, SAP-2 and SAP-4) appears to be necessary for superficial colonization and survival in environment with wide variation in availability of substrates like tongue dorsum. Results are in agreement with the literature, Saps 1, 2 are classes of proteinases secreted during the superficial oral infections, and in contrast, in systemic infections there is predominance of Sap-4.