Biochemical and histochemical studies of arylsulfatases in human lesions of endodontic origins

Date
1989
DOI
Authors
Aqrabawi, Jamal
Version
OA Version
Citation
Abstract
Lesions of endodontic origin are areas of inflammatory response which occur as a result of untreated disease processes within the root canal system. Lysosomal hydrolytic arylsulfatase A and B have been identified as major enzymes initiating and propagating bone loss by degrading chondroitin-4-sulfate (a major glycosaminoglycan of all hard tissues such as dentin, cementum and bone). Arylsulfatases have been recognized in tissues and cells implicated in the generation of slow reacting substance of anaphylaxis and in eosinophils which infiltrate the site of an immediate hypersensitivity reaction. The purpose of this investigation was to examine human lesions of endodontic origin for the presence of arylsulfatase A and B. Fifteen human lesions were collected, homogenized, centrifuged and dialysed against distilled water for 18 hours. Aliquots were incubated with the substrate nitrocatechol sulfate (NCS) for one hour at 37 [degrees]C. The reaction was terminated with NaOH. Arylsulfatase activity was determined spectrophotometrically by monitoring the liberated 4-nitrocatechol at 515 nm. Five control samples obtained from healthy periodontal ligaments were analyzed in a similar manner. In addition, five human lesions were examined histochemically by light and electron microscopy. For light microscopy, tissue specimens were fixed in 2% buffered glutaraldehyde for 24 hours at 4 [degrees]C and then rinsed for several hours. Sections 8 microns in thickness were cut with a cryotome and incubated for 1 hour at 37 [degrees]C using NCS as substrate and lead nitrate as capturing agent. For electron microscopy, the tissues were first cut into small blocks and then fixed with 2% buffered glutaraldehyde for 24 hours at 4 [degrees]C and incubated for 90 minutes at 37 [degrees]C using NCS as substrate and barium chloride as the capturing agent. Two control samples obtained from healthy periodontal ligaments were studied in a similar manner. The results showed higher levels of arylsulfatase A in lesions than in control tissues, and marked activity of arylsulfatase B in lesions whereas no activity of this enzyme was evident in the control specimen. Histochemically all lesions showed positive staining for enzyme activity whereas the controls were negative. The electron microscopic results demonstrated that lysosomal bodies were stained positively for the arylsulfatase activity in fibroblasts. These findings indicate that arylsulfatase A and B play a role in the pathogenesis of human lesions of endodontic origin.
Description
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Photographs included.
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1989 (Endodontics)
Bibliography : leaves 104-115.
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