Inducible Nitric Oxide Expression Correlates with the Level of Inflammation in Periapical Cysts

ABSTRACT

Objectives: In an attempt to elucidate if inducible nitric oxide expression (iNOS) is correlated with the level of inflammation in periapical cysts with accuracy, the goal of this study was to evaluate the expression of iNOS in these ones.

Methods: 30 cases were included in this study being iNOS evaluated by means of immunohistochemistry. Statistical analysis was performed by Kruskal-Wallis non-parametric test followed by the post-hoc Dunn’s test.

Results: iNOS stain was detected throughout the epithelium, subepithelial fibroblasts and macrophages in all cases, indistinctly. Nevertheless, iNOS immunostaining in periapical cysts was different according to the levels of inflammation, being the strongest effect associated with intense inflammatory infiltrate.

Conclusions: Taken together, our results indicate that immunoreactivity of iNOS was expressed in several cellular types present in periapical cyst, being positively correlated with the level of inflammation. Therefore, iNOS expression plays an important role in the pathogenesis of periapical cysts. (Eur J Dent 2007;1:212-215)

Key words

Periapical cyst - iNOS - Inflammation - Periapical cyst - Immunoreactivity

• References

• 1 Shear M. Cysts of the jaws: recent advances. J Oral Pathol 1985; 14: 043-049
• 2 Meghji S, Qureshi J, Harris M. The role of endotoxin and cytokines in the pathogenesis of odontogenic cysts. Arch Oral Biol 1996; 41: 523-531
• 3 Shafer WG, Hine MK, Levy BM. Diseases of the pulp and periapical tissues. A textbook of oral pathology. Philadelphia, W.B. Philadelphia, W.B: Saunders Company; 1983: 479-510
• 4 Stashenko P, Teles R, D’Souza R. Periapical inflammatory responses and their modulation. Crit Rev Oral Biol Med 1988; 9: 498-521
• 5 Fukumura P, Kashiwagi S, Jain RK. The role of nitric oxide in tumour progression. Nature Reviews Cancer 2006; 6: 521-534
• 6 Knowles RG, Moncada S. Nitric oxide syntheses in mammalian cells. Biochem J 1994; 298: 249-258
• 7 Hsu YY, Jou YT, Wong R, Karabucak B, Simchon S, Kim S. Effect of nitric oxide synthase inhibitor (L-NAME) on substance P-induced vasodilatation in the dental pulp. Int Endod J 2003; 36: 840-847
• 8 Takeichi O, Hayashi M, Tsurumachi T, Tomita H, Ogihara B, Ogiso B, Saito T. Inducible nitric oxide synthase activity by interferon-τ-producing cells in human radicular cysts. Int Endod J 1999; 32: 124-130
• 9 Suzuki T, Kumamoto H, Doya K, Motegi K. Expression of inducible oxide synthase and heat shock proteins in periapical inflammatory lesions. J Oral Pathol Med 2002; 31: 488-493
• 10 Kubes P, Suzuki M, Granger DN. Nitric oxide an endogenous modulator of leukocyte adhesion. Proc Natl Acad Sci 1991; 88: 4651-4655
• 11 Schroder A, Ney P, Woditsh I, Schoror P. Cyclic GMP mediates SIN-1-induced inhibition of human polymorphonuclear leukocytes. Eur J Pharmacol 1991; 182: 211-218
• 12 Kaplan SS, Biliar T, Curran RD, Adiziarski AV, Simmon RL, Besford RE. Inhibition of chemotaxis with NG-monomethyl- L-arginine: a role for cyclic GMB. Blood 1989; 74: 1885-1887
• 13 Alvina JE, Cui C, Mateo RB, Reicher JS. Nitric oxide mediated apoptosis in murine peritoneal macrophages. J Immunol 1993; 5080-5085
• 14 Stuehr DJ, Nathan CF. Nitric oxide. A macrophage product responsible for cytostasis and respiratory inhibition in tumor target cells. J Exp Med 1989; 169: 1543-1555
• 15 Lepoivre M, Coves J, Fontecave M. Inhibition of ribonucleotide reductase by nitric oxide. In: Moncada S, Marletta MA, Hibbs Jr JB, Higgs EA. Eds. Biology of Nitric Oxid. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1992; 0 part 2
• 16 Breft DS, Hwang PM, Glatt CE, Lowenstein C, Reed RR, Snyder SH. Cloned and expressed nitric oxide synthase structurally resembles cytochrome p-450 reductase. Nature 1991; 351: 714-718
• 17 Beevi SS, Rasheed AM, Geetha A. Evaluation of oxidative stress and nitric oxide levels in patients with oral cavity cancer. Jpn J Clin Oncol 2002; 24: 379-385
• 18 Nathan C, Xie QW. Nitric oxide synthases: roles, tolls, and controls. Cell 1994; 78: 915-918