Immunocytochemical Distribution of Human PMN Elastase and Cathepsin-G in Dental Pulp

Abstract

Components of primary (azurophilic) granules of polymorphonuclear leukocytes (PMNs) have been implicated as important mediators in pulpal inflammation. This anatomical study used ultracryoimmunocytochemical techniques and characterized and contrasted the subcellular distributions of human PMN elastase (PMN-E), PMN cathepsin-G (PMN-CG), and alpha-2 macroglobulin (a-2M) in healthy and inflamed dental pulps. Inflamed pulpal tissue sections revealed an intense distribution of PMN-E in the extracellular domain throughout the collagen matrix. PMN-E was also localized in the perinuclear cytoplasm of PMNs and distributed in a random fashion. PMN-CG was localized intensely in the intracellular granules of PMNs and observed moderately within the extracellular matrix. Healthy pulpal tissues exposed to PMN-E and PMN-CG antibodies revealed no evidence of PMN infiltration and no specific labeling. a-2M, a natural serum inhibitor of PMN-E and PMN-CG, was distributed in an intense fashion within the intravascular compartments of both inflamed and healthy pulpal samples. Immunogold-labeling for a-2M was observed in moderate amounts within the extravascular domain of inflamed pulpal samples but only in mild amounts within the same area of healthy tissues. These results suggest that PMN-E and PMN-CG are released to the extracellular matrix of irreversibly inflamed teeth, enabling them to facilitate pulpal connective tissue destruction. Conversely, moderate extravascular labeling for a-2M within inflamed samples suggests a physiological attempt at inhibiting the pulpal connective tissue destruction mediated by human PMN-E and PMN-CG.

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References

Fujisawa T. , Kephart GM , Gray BH , Gleich GJ (1990). The neutrophil and chronic allergic inflammation. Immunochemical localization of neutrophil elastase. Am Rev Respir Dis 141:689-697.

Gadek JE , Fells GA , Wright DG , Crystal RG (1980). Human neutrophil elastase functions as a type III collagen "collagenase". Biochem Biophys Res Commun 95:1815-1822.

Heck LW , Blackburn WD , Irwin MH , Abrahamson DR (1990). Degradation of basement membrane laminin by human neutrophil elastase and cathepsin G. Am J Pathol 136:1267-1274.

Maita E. , Tao L. , Simpson M. , Pashley DH (1990). Dentinal fluid dynamics, in vivo (abstract). J Dent Res 69:356.

McClanahan SB , Turner DW , Kaminski EJ , Osetek EM , Heuer MA (1991). Natural modifiers of the inflammatory process in the human dental pulp. J Endodont 17:589-593.

McDonald JA , Kelly DG (1980). Degradation of fibronectin by human leukocyte elastase. Release of biologically active fragments. J Biol Chem 255:8848-8858.

Morand MA , Schilder H. , Blondin J. , Stone PJ , Franzblau C. (1981). Collagenolytic and elastinolytic activities from diseased human dental pulps. J Endodont 7:156-160.

Rauschenberger CR , Turner DW , Kaminski EJ , Osetek EM (1991). Human polymorphonuclear granule components: relative levels detected by a modified enzyme-linked immunosorbent assay in normal and inflamed dental pulps. J Endodont 17:531-536.

Reeves R. , Stanley HR (1966). The relationship of bacterial penetration and pulpal pathosis in carious teeth. Oral Pathol 22:59-65.

10.

Shuttleworth CA , Ward JL , Hirschmann PN (1978). The presence of type III collagen in the developing tooth. Biochem Biophys Acta 535:348-355.

11.

Simpkins CO , Alailima ST , Tate EA , Johnson M. (1986). The effect of enkephalins and prostaglandins on O2 release by neutrophils. J Surg Res 41:645-652.

12.

Smedly LA , Tonnesen MG , Sandhaus RA , Haslett C. , Guthrie LA , Johnston RB , et al. (1986). Neutrophil-mediated injury to endothelial cells. Enhancement by endotoxin and essential role of neutrophil elastase . J Clin Invest 77:1233-1243.

13.

Tokuyasu KT (1986). Application of cryoultramicrotomy to immunocytochemistry . J Microscopy 143:139-149.

14.

Tokuyasu KT (1989). Use of poly(vinyl) pyrrolidone and poly(vinyl) alcohol for cryoultramicrotomy. Histochem J 21:163-171.

15.

Torneck CD (1977). Changes in the fine structure of the human dental pulp subsequent to carious exposure. J Oral Pathol 6:82-95.

16.

Trapp BD , Andrews SB , Cootauco C. , Quarles R. (1989). The myelin-associated glycoprotein is enriched in multivesicular bodies and periaxonal membranes of actively myelinating oligodendrocytes. J Cell Biol 109:2417-2426.

17.

van Amerongen JP , Lemmens IG , Tonino GJ (1983). The concentration, extractability and characterization of collagen in human dental pulp. Arch Oral Biol 28:339-345.