Uticaj sojnih razlika na patogenezu periapikalnih lezija zuba u dva soja pacova Dark Agouti i Albino Oxford

Abstract

Uvod Periapikalne lezije nastaju kao posledica dejstva mikroorganizama i njihovih produkata iz inficiranog kanala na periapikalno tkivo. Ova inflamacija može stimulisati destrukciju periapikalnih tkiva i uzrokovati resorpciju alveolarne kosti pri čemu nastaje periapikalna lezija. Periapikalne lezije nemaju uvek iste karakteristike. Ćelije i medijatori inflamacije koje su povezani sa razvojem i veličinom periapikalnih lezija nisu u potpunosti razjašnjeni. Genetska podloga eksperimentalnih životinja može uticati na patogenezu bolesti. Dark Agouti i Albino Oxford pacovi se razlikuju u osetljivosti na inflamatorne stimuluse i na indukciju eksperimentalnih autoimunih bolesti. Cilj Cilj ove studije je bio da ispita efekte razlika u imunološkoj reaktivnosti na indukciju periapikalnih lezija. Materijal i metode Periapikalne lezije su indukovane kod DA i AO pacova izlaganjem pulpe desnih mandibularnih molara oralnoj sredini. Žrtvovanje životinja je urađeno 21 dan nakon indukcije periapikalnih lezija, mandibule su izolovane i pripremljene za radiografsku i patohistološku analizu. Na ćelije periapikalnih lezija primenjen je PCR u realnom vremenu i protočna citometrija. Nivo citokina i parametra okisidativnog stresa su mereni iz prikupljenih uzoraka krvi i supernatanta homogenata periapikalnih lezija. Dobijeni rezultati analizirani su u softverskom programu za statističku analizu podataka Statistical Package for Social Sciences v23.0. Statistička analiza je urađena parametarskim One-Way ANOVA i T- testom nezavisnih uzoraka i neparametarskim testovima Kruskal-Wallis H i Mann-Whitney U zavisno od normalne raspodele podataka. Statistički značajna razlika u dobijenim vrednostima između grupa je smatrana kad je r<.05. Rezultati Radiografskom i patohistološkom analizom je pokazano da su DA pacovi razvili veće periapikalne lezije u odnosu na AO pacove. Infiltracija neutrofilima i makrofagima je bila značajno izraženija u periapikalnim lezijama DA pacova. Protočnom citometrijom je pokazan veći procenat T ćelija, kao i INF-γ CD3+CD4+, IL17 CD3+CD4+, i IL-10 CD3+CD4+ ćelija u periapikalnim lezijama DA pacova. Ekspresija gena koji kodiraju citokine IL-1β, INF-γ, i IL-17 je bila veća kod DA pacova. Ekspresija RANKL je bila značajno veća kod DA pacova, dok je ekspresija OPG bila veća kod AO pacova. RANKL/OPG odnos je značajno veći u DA pacova. Patološki proces u periapikalnim lezijama se reflektuje i na sistemski nivo proinflamatornih citokina: TNF-α i IL-6 je veći kod DA pacova. Markeri oksidativnog stresa u sistemskoj cirkulaciji i supernatantu homogenata periapikalnih su izraženiji u DA pacovima. Zaključak DA pacovi su razvili veće periapikalne lezije u odnosu na AO pacove. Genetski uslovljena razlika u imunološkoj reaktivnosti snažno utiče na patogenezu eksperimentalnih periapikalnih. Poznavanje genetski zasnovanih razlika može doprineti razumevanju mehanizmima koji povećavaju inflamaciju i progresiju periapikalnih lezija.

Introduction Periapical lesions develop as a consequence of microorganisms and their products from the infected canal on the periapical tissue. This inflammation can stimulate the destruction of periapical tissues and cause resorption of the alveolar bone, developing periapical lesion. Periapical lesions do not always have the same characteristics. Inflammatory cells and mediators associated with the development and size of periapical lesions have not been fully elucidated. The genetic background of experimental animals may influence the pathogenesis of the disease. Dark Agouti and Albino Oxford rats differ in their sensitivity to inflammatory stimuli and in the induction of experimental autoimmune diseases. Aim The aim of this study was to determine the effects of differences in immune reactivity on the induction of periapical lesions. Material and methods Periapical lesions were induced in DA and AO rats by exposing the pulp of the right mandibular molars to the oral environment. Animal sacrifice was performed 21 days after induction of periapical lesions, mandibles were dissected and prepared for radiographic and pathohistological analysis, as well as for the real-time PCR and flow cytometry. Cytokine levels and oxidative stress parameters were measured from collected blood samples and supernatant of homogenous periapical lesions. The obtained results were analyzed in the software program for statistical data analysis Statistical Package for Social Sciences v23.0. Statistical analysis was performed by parametric One-Way ANOVA and T-test of independent samples and nonparametric tests Kruskal-Wallis H and Mann - Whitney U depending on the normal data distribution. A statistically significant difference in the obtained values between the groups was considered when p<.05. Results Radiographic and pathohistological analysis showed that DA rats developed larger periapical lesions compared to AO rats. Infiltration by neutrophils and macrophages was significantly more pronounced in periapical lesions of DA rats. Flow cytometry showed a higher percentage of CD3 + cells, as well as INF-γ CD3 + CD4 +, IL-17 CD3 + CD4 +, and IL-10 CD3 + CD4 + in periapical DA lesions. Expression of genes encoding the cytokines IL1β, INF-γ, and IL-17 was higher in DA rats. RANKL expression was significantly higher in DA rats, while OPG expression was higher in AO rats. The RANKL/OPG ratio was shown to be higher in the periapical lesions of DA rats. The pathological process in periapical lesions is also reflected on the systemic level of proinflammatory cytokines: TNF-α and IL-6 are higher in DA rats. Markers of oxidative stress in the systemic circulation and periapical homogenate supernatant are more pronounced in DA rats. Conclusion DA rats developed larger periapical lesions compared to AO rats. The genetically determined difference in immune reactivity strongly influences the pathogenesis of experimental periapical lesions. Knowledge of genetically based differences may contribute to understanding the mechanisms that increase inflammation and progression of periapical lesions.