Effect Of CORM-2on Experimental Periodontitis In Rats

Objective:Periodontitis is in fact an infectious disease initiated by periodontal pathogens reside in dental plaque, resulting in destruction of periodontal soft tissues, resorption of alveolar bone and tooth loss eventually. Inhibition of host inflammatory response is therefore regarded as an effective way to block the pathological process. The anti-inflammatory properties of CO were identified in vivo and in vitro there years. CO can inhibit the production of inflammatory mediators such as TNF-α, IL-1β and IL-8. CO-releasing molecules (CORMs) are a novel group of compound that are capable of modulating physiological functions as CO via the liberation of CO. In this experiment, we used an in vivo model to investigate the effects of CORM-2(carbon monoxide releasing molecue-2) on ligature-induced experimental periodontitis and related alveolar bone loss in rats.Methods:1. Fourty-two male Wistar rats weighing210(±20g) on average were divided into three groups randomly:non-ligated(NL), ligature only(LO), and ligature and treated with CORM-2(CO). Rats in NL group did not receive any procedure, while animals were ligatured and treated with saline solution (NaCl0.9%)(LO group), or treated with CORM-2(10mg/kg per day)(CO group). A3/0silk suture was placed around the mandibular first molars.2. Rats were sacrificed after3,7and10days. Blood samples were collected from all animals for analysis of TNF-α and IL-1β.3. Mandibles were stained with aqueous methylene blue (1%) after the gingival were dissected. Then changes in alveolar bone levels were measured clinically.4. The mandibles were decalcified in aqueous of10%EDTA solution, then dehydrated and embedded in paraffin, sectioned in a bucco-lingual plane in5μm thickness and stained with haematoxylin-eosin (H&E). Periodontal tissues were histopathologically examined to assess the infiltration of inflammatory cells.Results:1. The experimental periodontitis were successfully induced by placement of3/0silk suture around the cervix of mandibular first molars in all modal animals.2. Trace amounts of TNF-α and IL-1β were found in serum of NL group. The serum levels of TNF-α and IL-1β in LO group were significantly higher than that in CO and NL groups (p<0.05). And the serum levels of TNF-α and IL-1β increased along with the experimental progress.3. Ligature placement increased alveolar bone loss and increased inflammatory cell infiltration in periodontal tissue. Alveolar bone loss was significantly higher in LO group than that of the NL and CO groups (p<0.05).4. The ratio of presence of inflammatory cell infiltration (ICI) score2in LO group (87.3%vs.16.7%and0%) was significantly higher compared to CO and NL groups (p<0.05).Conclusions:This study has demonstrated that systemic administration of CORM-2reduced periodontal inflammation and alveolar bone loss in experimental periodontitis in rats, which shows an interesting therapeutic potential on periodontal disease.