Effect Of The Chitosan Thermosensitive Hydrogel Loading Panax Notoginseng Saponins On Healing Process Of Tooth Extraction And Expression Of BMP-2 In Rat

Objective:Due to the limitations of medicine,there are varieties of local or systemic factors so that we have to remove the teeth in current clinical work.After tooth extraction,the healing process directly determines whether the patient can wear denture in good time.Additionally the form and function of the local alveolar ridge after reconstruction of the extraction socket have effects on the retention and stabilization of the denture,the orthodontic movement of the adjacent teeth,and the bone condition of the artificial implantation.Therefore the important topic has got doctors' common concern from departments of oral and maxillofacial surgery,prosthodontics,orthodontics and implant dentistry.The aim of this study was to investigate the effect of the chitosan thermosensitive hydrogel loading Panax notoginseng saponins on healing process of tooth extraction and whether it could effectively control absorption of the residual alveolar ridge and expression of BMP-2 in rats.Methods:Forty eight male SD rats(3 months age,weighing 200-250 g)were were used in the experiment.The crowns of the left mandibular incisors the gripping margin were removed along gingival marginby using a portable dental drill at 9 days,6 days and 3 days before tooth extraction.The rats can not establish occlusal relationship before tooth extraction,and three of the rats were died during the period.On the tenth day,the remaining 45 rats were divided into five groups(high concentration group,medium concentration group,low concentration group,blank gel groupand complete blank group).After removal of the left mandibular incisors,the first four groups were respectively placed high concentration of Panax notoginseng saponins(2.8mg/ml),medium concentration of Panax notoginseng saponins(1.4mg /ml),low concentration of Panax notoginseng saponins(0.7mg/ml)and blank gel(0mg/ml).Each Tooth extraction was placed 20 ul of drug.Blank control group did not place anything.Three rats of each group were randomly selected and killed on 7,14,28 days after tooth extraction by heart perfusion fixation method.The left and right mandibulars were stripped from rats.Then we took digital radiographs of left and right mandibulars and the relative lengths of the remaining alveolar ridges were measured.At last,we made pathological sections to observe the healing of tooth extraction though HE staining and detect the expression of BMP-2 by immunohistochemical staining.Results:1.The statistical results of the relative length of the remaining alveolar ridges in each group showed that there were no statistical differences between the five groups at the 7th day.While at the 14 th day and 28 th day,values of the three drug groups were higher than that of blank gel group and completely blank group.Among the three drug groups,values of the medium concentration group were the highest.There were no statistical significances between the value of the high concentration group and the low concentration group.Neigher were between blank gel group and completely blank group.When comparisons were made at different time points within the same group,there were no statistical differences between the values of the 7th day and the 14 th day.While the values of the 28 th day were the lowest among the three time points.2.The amounts of BMP-2 positive cells were compared between the three drug groups and the complete blank group,and the former weresignificantly higher than the latter at the 3 time points.At 3 time points,the drug loading groups were significantly higher than the blank gel group,and the differences were statistically significant.At 3 time points,The amounts of the medium concentration group were significantly higher than that of the high and low groups,which was statistically significant.While there were no significant differences between the amounts of blank gel group and complete blank group,nether were between the high concentration group and the low concentration group.3.The results of HE staining were consistent with the immunohistochemistry results above.Conclusions:The total saponins of Panax notoginseng can increase the expression of BMP-2 and inhibit the absorption of alveolar bone.The effect of Panax snotoginsen saponinare in the medium dose group(1.4mg/ml)is better than that in high dose group(2.8mg/ml)and low dose group 0.7mg/ml;).The chitosan thermosensitive hydrogel has certain osteogenic induction effect,but the effect is not obvious.