| Objective: Ankylosis is a common clinical complication after replantation of avulsed tooth.The main reason is that the teeth are stored in an improper solution and the viability of cell on the root surface has been lost.Healing with a normal periodontal ligament is the optimal manner.Therefore,maintaining the viability of the survival cells on the root surface is very important to save the avulsed tooth and increase the success rate of replanted tooth.Stem cells involved in periodontal ligament regeneration include periodontal ligament stem cells(PDLSCs),stem cells from apical papilla,and bone marrow-derived mesenchymal stem cells from jaw bone and so on.PDLSCs are critical to periodontal healing due to its powerful potential of periodontal regeneration.PDLSCs can differentiate into cementoblast-like cells and collagen-forming cells.The ideal storage medium of avulsed tooth should maintain the cell viability for a long time.Hank’s balanced salt solution(HBSS)is recommended by the International Association of Dental Traumatology as the storage medium for avulsed teeth.However,it has not been widely used because the period it preserve cell activity is limited.Conditioned medium from PDMSCs(PDMSCs-CM)contain many kinds of secreted factors.Many growth factor could maintain the viability and promote the proliferation of mesenchymal stem cell.Therefore,the aim of the present study was to compare the biological effects of PDMSCs-CM on the viability and proliferation of PDLSCs with HBSS,in order to find a more ideal storage medium for avulsed tooth and promote the healing of periodontal ligament.Methods: Isolation and culture of the PDLSCs,fluorescent-activated cell sorting was used to assess the surface marker expressions of PDLSCs.Osteogenic differentiation and adipogenic differentiation assay of PDLSCs was used to assess the ability of multipotential differentiation.Testing the p H of HBSS and PDMSCs-CM.PDLSCs was treated with HBSS or PDMSCs-CM.The CCK-8 assay and cell cycle test were used to assess the proliferation and viability of PDLSCs.The ratio of PDLSCs apoptosis was detected by flow cytometry.Data were statistically analyzed by the least significance difference(LSD)method using SPSS 17.0 software.P values less than 0.05 were considered statistically significant.Results: The primary PDLSCs had spindle-shaped cells.PDLSCs had good capacity of multi-potential differentiation and expressed the mesenchymal stem cell surface markers.The p H value of PDMSCs-CM and HBSS were 7.48 ± 0.05 and 7.41 ± 0.03 and there were no significant distinction with the conventional medium(P > 0.05).The number and morphology of PDLSCs changed after treated with HBSS in 12 h.The number and morphology of PDLSCs treated with PDMSCs-CM had no significant distinction with the cells in conventional medium.The proliferation rate of PDLSCs was decreased after being treated with HBSS from 12 h(P < 0.05).The proliferation rate of PDLSCs was decreased after being treated with PDMSCs-CM from 72 h but the number of cell was still increased(P < 0.05).The cell cycle of PDLSCs treated with HBSS showed that the G2+S phase were lower,while the G1 phase were high.The cell cycle of PDLSCs treated with PDMSCs-CM showed that the G2+S phase were raised after 12 h.HBSS can induce apoptosis of PDLSCs after12 h and the apoptosis rate reached 64.17% ± 4.65% at 48 h,which was significantly higher than that of the control group(P < 0.05).PDMSCs-CM had no influence on the apoptosis of PDLSCs.The apoptosis rate of PDLSCs cells in PDMSCs-CM group was not significantly different from that of the control group during the detection time(P > 0.05).Conclusions: Compared with HBSS,PDMSCs-CM could maintain the activity of PDLSCs for a longer period of time up to 48 hours.It could serve as storage medium for avulsed tooth. |
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