Relationships between periapical lesion and IL-1, TNF-alpha gene expression in rat / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To understand the effects of the IL-1, TNF-alpha cytokines on the pathogenesis of periapical lesions by investigating its gene expression in rat.</p><p><b>METHODS</b>The model was established by surgically exposing mandibular molar teeth and left open to permit infection from the oral environment. The SD rats were killed at 1, 2, 3, 4 weeks and mandibular molar teeth X-ray were taken. In situ hybridization was used to test IL-1alpha, IL-1beta, TNF-alpha mRNA expression in periapical area and the kinds of positive cells were identified. Using image analysis system analyzed gene expression semi-quantified.</p><p><b>RESULTS</b>IL-1alpha, IL-1beta and TNF-alpha mRNA were all expressed beginning at 1 week, peaked at 3 weeks, and declined somewhat at 4 weeks, but IL-1beta mRNA was expressed at much lower levels with the same kinetics (P<0.01). Most of the staining occurred in areas that had heavy inflammatory infiltrate, fibroblasts, or endothelial cells. There was a statistically significant correlations between the area of periapical lesion and the number of positively stained cells for IL-1alpha and for TNF-alpha (IL-1alpha r=0.875, P<0.001; TNF-alpha r=0.858, P<0.001), and between the number of positive cells for IL-1alpha and that of for TNF-alpha (r=0.969, P<0.001).</p><p><b>CONCLUSIONS</b>IL-1alpha and TNF-alpha genes are highly expressed in developing periapical lesions in rat, which supports the hypothesis that these two cytokines play a key role in pulpal and periapical pathogenesis, including the concomitant bone destruction.</p>