Anti-ageing effects of dentifrices containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) on gingival collagen degradation in rats.

OBJECTIVE: Previous studies have demonstrated the relationship between ageing and oxidative stress. In this study, we examined the effects of topical application of a dentifrice containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) to the gingival surface on gingival collagen degradation in rats. DESIGN: Fischer 344 male rats (4 or 8 months old) were divided into two groups: experimental group and control group. Tomarina® (the experimental group) or control dentifrice (the control group) was applied 5 days per week for 2 months. RESULTS: In the control group, gingival collagen density decreased with ageing. In the experimental group, the collagen density did not change with ageing, and was greater than that in the control group at 10 months of age (p < 0.0083). In addition, the control group showed an increase in serum oxidative stress with ageing. The experimental group also showed increased serum oxidative stress, but the value was lower than the control group at 10 months of age (p < 0.0083). Furthermore, low expressions of protein oxidative damage in the periodontal tissue were observed in the experimental group, compared to the control group at 6 months and 10 months. CONCLUSION: These findings indicate that Tomarina® might suppress the effects of ageing on gingival collagen degradation, by decreasing oxidative stress in the rat model.

Supplementation of broccoli or Bifidobacterium longum-fermented broccoli suppresses serum lipid peroxidation and osteoclast differentiation on alveolar bone surface in rats fed a high-cholesterol diet.

High-cholesterol diet enhances osteoclastic activity on alveolar bone by increasing serum lipid peroxidation. We hypothesized that supplementation with dietary antioxidants, such as found in broccoli and its fermented products, might suppress increases in serum lipid peroxidation, contributing to the inhibition of osteoclastic activity after high-cholesterol diet intake. The purpose of the present study was to investigate the effects of broccoli and fermented broccoli consumption on serum lipid peroxidation and osteoclast differentiation in alveolar bone of rats fed a high-cholesterol diet. In this 12-week study, rats were divided into 4 groups (n = 6/group): a control group (fed regular diet) and 3 experimental groups (fed a high-cholesterol [1% wt/wt] diet, or a high-cholesterol diet supplemented with either broccoli powder [5% wt/wt] or Bifidobacterium longum-fermented broccoli powder [5% wt/wt]). Serum hexanoyl-lysine (HEL) levels were measured as a parameter of lipid peroxidation. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts in alveolar bone was enumerated to evaluate osteoclast differentiation. When compared with regular diet, the high-cholesterol diet increased serum HEL levels and resulted in a higher number of TRAP-positive osteoclasts at 12 weeks. The high-cholesterol diet supplemented with broccoli or B. longum-fermented broccoli showed lower levels of serum HEL and fewer TRAP-positive osteoclasts than the high-cholesterol diet at 12 weeks. In conclusion, consumption of broccoli, or its fermented product, inhibited the effects of a high-cholesterol diet on osteoclast differentiation in rat alveolar bone by suppressing serum lipid peroxidation.

Hydrogen-rich water attenuates experimental periodontitis in a rat model.

AIM: Reactive oxygen species (ROS) contribute to the development of periodontitis. As molecular hydrogen can act as a scavenger of ROS, we examined the effects of treatment with hydrogen-rich water on a rat model of periodontitis. MATERIAL & METHODS: A ligature was placed around the maxillary molars for 4 weeks to induce periodontitis, and the animals were given drinking water with or without hydrogen-rich water. RESULTS: The rats with periodontitis which were treated with pure water showed a time-dependent increase in serum ROS level. Compared with the rats without periodontitis, the periodontitis-induced rats which were given pure water also showed polymorphonuclear leucocyte infiltration and alveolar bone loss at 4 weeks. Hydrogen-rich water intake inhibited an increase in serum ROS level and lowered expression of 8-hydroxydeoxyguanosine and nitrotyrosine in the periodontal tissue at 4 weeks. Such conditions prevented polymorphonuclear leucocyte infiltration and osteoclast differentiation following periodontitis progression. Furthermore, inflammatory signalling pathways, such as mitogen-activated protein kinases, were less activated in periodontal lesions from hydrogen-rich water-treated rats as compared with pure water-treated rats. CONCLUSION: Consuming hydrogen-rich water might be beneficial in suppressing periodontitis progression by decreasing gingival oxidative stress.

Supplementation of green tea catechins in dentifrices suppresses gingival oxidative stress and periodontal inflammation.

OBJECTIVE: this study examined the effects of a dentifrice containing green tea catechins on gingival oxidative stress and periodontal inflammation using a rat model. DESIGN: twenty-four male Wister rats were randomly divided into four groups. The first group (Control group) received no treatment for 8 weeks. Periodontal inflammation was induced in the second group for 8 weeks. Periodontal inflammation was induced in the last two groups for 8 weeks and dentifrices with or without green tea catechins were topically applied to the gingival sulcus daily for 4 weeks prior to the end of the experimental period. RESULTS: rats that had experimental periodontal inflammation showed apical migration of the junctional epithelium, alveolar bone loss and inflammatory cell infiltration in the connective tissue subjacent to the junctional epithelium at 8 weeks, whilst the control group showed no pathologic changes. Topical application of a green tea catechin-containing dentifrice reduced inflammatory cell infiltration in the periodontal lesions to a greater degree than the control dentifrice at 8 weeks. The gingiva in which green tea catechin-containing dentifrice was applied also showed a lower level of expression of hexanoyl-lysine (a marker of lipid peroxidation), nitrotyrosine (a marker of oxidative protein damage), and tumour necrosis factor-α (an indicator of pro-inflammatory cytokines) at 8 weeks compared to gingiva in which the control dentifrice was applied. CONCLUSIONS: adding green tea catechins to a dentifrice may contribute to prevention of periodontal inflammation by decreasing gingival oxidative stress and expression of pro-inflammatory cytokines.