[Effect and mechanism of testosterone level on inflammatory bone resorption in periodontitis with mice]

To investigate the effect of testosterone level on inflammatory bone resorption in periodontitis with mice.

Forty-eight SD mice were randomly divided into unligated group, sham operation group, castration group, castration + testosterone group, 12 mice in each group. At 6 weeks after ligation, serum testosterone levels were measured, and alveolar bone loss (ABL) and alveolar bone absorption area were compared by hematoxylin - eosin staining and methylene blue staining. The expression of inflammatory cytokine messenger RNA(mRNA) in gingival tissue was measured by real-time fluorescence quantitative PCR. SPSS 20.0 software package was used to analyze the data.

Serum testosterone level among four groups was the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference(P<0.05). The ABL of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The ABL of the castration group was significantly smaller than that of the sham operation group (P<0.05). The alveolar bone resorption area of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The alveolar bone resorption area of the castration group was significantly smaller than that of the sham operation group (P<0.05). Interleukin-1β (IL-1β) mRNA, interleukin-6(IL-6) mRNA and tumor necrosis factor-α(TNF-α) mRNA levels in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly higher than the unligated group. The levels of interleukin-10(IL-10) mRNA in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly lower than those in unligated group(P<0.05). The level of IL-1β mRNA in gingival tissues among four groups was the the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference (P<0.05). Serum testosterone levels were positively correlated with ABL, alveolar bone resorption area, and IL-1β (P<0.05).

Periodontitis with mice have decreased testosterone levels, and long-term testosterone depletion can reduce inflammatory bone resorption in alveolar bone, which may be achieved by reducing the level of IL-1β, indicating that reduction of the level of testosterone in periodontitis patients may be a new treatment target for alveolar bone resorption.