Gender Serum Cytokine Differences in Rats with Periapical Abscesses

Objective: The objective of this study was to determine gender differences in serum cytokine concentrations in response to induced periapical inflammation. Methods: Spague-Dawley rats were divided into four groups: females with induced periapical inflammation (n=10), sham-operated control females (n=8), males with induced periapical inflammation (n=16), and sham operated control males (n=16). To induce periapical inflammation, the pulps of the first and second maxillary right molars were exposed using a ¼ round burr in a high-speed handpiece. Once bleeding ceased, 0.5µl of sterile bacterial lipopolysaccharide was placed in each pulp chamber to promote inflammation. Twenty-eight days later, serum and maxillas were collected from the rats. Serum IL-6, TNF-alpha, and IL-1b concentrations were measured by ELISA. Maxillas were cleaned of residual tissue and digital radiographs were taken to verify the presence of periapical abscesses. Cytokine data were compared by factorial ANOVA, post-hoc Tukey, and Pearson correlation tests. Results: Both male and female rats with periapical abscesses had significantly higher concentrations (p<0.05) of serum IL-6, TNF-alpha, and IL-1b when compared to controls. Males with abscesses had significantly higher concentrations (p<0.05) of serum IL-6, TNF-alpha, and IL-1b when compared to females with abscesses. Conclusion: Induced periapical inflammation led to increased serum concentrations of systemic inflammatory markers in both male and female rats. However, the male rats had a more severe systemic response to the same type of oral inflammation. There is increased evidence that periodontal inflammation can be a risk factor for systemic illness, our data indicates that periapical inflammation could also be a significant risk factor for adverse systemic response. In addition, our data suggest that males have increased risk for adverse systemic reactions from this type of oral inflammation than females.