| Background:Antidepressant is the main treatment for depression.With the increase of the incidence of depression in recent years,antidepressants have become one of the most commonly used prescription drugs in the world.Selective serotonin(5-HT)reuptake inhibitors(SSRIs)are common antidepressants in most countries.Their main pharmacological effect is to selectively inhibit the reuptake of 5-HT in the presynaptic membrane and increase the concentration of 5-HT in the synaptic space.Sertraline,as a common SSRIs,is widely used in the treatment of depression,and also in the treatment of panic disorder,obsessive-compulsive disorder,post-traumatic stress disorder and other psychological disorders.With the widespread use of antidepressants,the effects of antidepressants on bones have also attracted more and more attention.Although there are some debate in this field,a considerable number of studies have described the possible link between SSRIs and bone metabolism.Some studies have found that SSRIs may reduce bone density,inhibit osteoblast differentiation and mineralized nodule deposition.One study reported that the activity of osteoclasts was not interfered by the intervention of SSRIs,but other studies showed that sertraline reduced the activity of osteoclasts.Orthodontic tooth movement(OTM)is the result of alveolar bone remodeling caused by orthodontic force.Osteoclasts on the compression side induce bone resorption,while osteoblasts on the tension side mediate osteogenesis.In view of the extensive use of antidepressants and the effect of SSRIs on bone metabolism,this research established rat OTM models to study the effect of sertraline on OTM and bone structure.In addition,the effect of sertraline on osteogenesis of periodontal ligament stem cells(hPDLSCs)was further studied in vitro.Objective:To investigate the effects of sertraline on orthodontic tooth movement,orthodontic root resorption and bone structure in rats.In addition,the effects of sertraline on the proliferation and osteoblasic differentiation were studied in vitro.Materials and Methods:1.Effects of sertraline on orthodontic tooth movement,root resorption and alveolar bone in rats.(1)Fifty-four male Wistar rats aged 6 weeks were used.After adaptive feeding for one week,they were divided into 3 groups randomly:control group(n=18),low-dose sertraline group(n=18)and high-dose sertraline group(n=18).All rats established orthodontic tooth movement model,and applied 50 g orthodontic force to the maxillary first molar.The rats in control group were intraperitoneally injected with 0.9%normal saline every day,the rats in the low-dose sertraline group were intraperitoneally injected with 5 mg/kg sertraline everyday,and the rats in the low-dose sertraline group were intraperitoneally injected with 20 mg/kg sertraline everyday.(2)After 7 and 14 days of orthodontic treatment,half of the rats were killed respectively.After heart perfusion,maxilla specimens containing right molars were obtained.The tooth movement distance was measured,and micro-computed tomography(Micro-CT)scanning,tartrate resistant acid phosphatase(TRAP)staining and immunohistochemistry(IHC)staining were performed.Micro-CT is used to analyze alveolar bone parameters and root resorption.Immunohistochemical staining is used to observe the expression of receptor activator of nuclear factor-κB ligand(RANKL),osteocalcin(OCN),runt-related transcription factor 2(Runx2)and osteoprotegerin(OPG).2.Effect of sertraline on the proliferation and osteoblastic differentiation of human periodontal ligament stem cells(hPDLSCs).(1)Periodontal ligament stem cells were isolated and cultured from periodontal tissues by tissue block method.The expression of cell surface markers CD34,CD45,CD90 and CD 105 was detected by flow cytometry.The cells were inoculated in the osteogenic and adipogenic inducing solution for osteogenic induction and adipogenic induction,and the multi-directional differentiation potential of hPDLSCs was identified.(2)The effect of sertraline(0,0.1,1,10 and 100 μmol/L)on the proliferation of hPDLSCs at different time points(1 d,3 d and 5 d)was detected by cell counting kit-8(CCK-8).(3)The effect of different concentrations of sertraline(0,0.1,1 and 10 μmol/L)on the deposition of mineralized matrix was observed by alizarin red-S staining.Alkaline phosphatase(ALP)test kit was conducted to detect the effect of sertraline(0,0.1,1 and 10μmol/L)on the activity of ALP.The effects of sertraline groups(0.1 and 10 μmol/L)and control group on the expression of osteogenesis-related genes(ALP,Runx2 and Osterix)were detected by qRT-PCR.Western blot was used to detect the expression levels of the osteogenesis-related proteins(ALP,Runx2 and Osterix)in sertraline groups(0.1 and 10μmol/L)and control group.In order to further explore the effect of sertraline on the osteoblastic differentiation of cells.Results:1.Effects of sertraline on orthodontic tooth movement,root resorption and alveolar bone in rats.(1)At 7 and 14 days,there were no significant differences in tooth movement among groups.The results of Micro-CT scanning analysis showed that all groups had root resorption areas at the 14th day,and there was no significant difference in root resorption between sertraline groups and control group,although the resorption of high-concentration sertraline group seemed to have a downward trend.Micro-CT based trabecular evaluation showed that at the 14th day,BV/TV and Tb.Th in sertraline groups on the tension side were lower than those in the control group(P<0.05).Tb.SP increased slightly,but there was no statistical significance.Besides,there was no significant difference in BV/TV,Tb.Th and Tb.Sp between sertraline groups and control group on compression side.(2)The results of TRAP staining showed that there was no significant difference in the number of TRAP-positive cells among the sertraline groups and control group on the 7th day.While on the 14th day,the number of TRAP-positive cells in the high-dose sertraline group was significantly lower than that in the control group(P<0.05).(3)The results of immunohistochemical staining showed that the mean optical density(MOD)of RANKL in the high-dose sertraline group was lower than that in the control group at the compression side(P<0.05).On the tension side,the expression of Runx2 and OCN in sertraline groups decreased(P<0.05),and the high-concentration group was lower than the low concentration group(P<0.05).2.Effect of sertraline on the proliferation and osteoblastic differentiation of hPDLSCs.(1)hPDLSCs was successfully isolated and cultured.The results of flow cytometry showed that the mesenchymal stem cells specific surface markers CD90 and CD 105 were positive,while the hemopoietic stem cell markers CD34 and pan-leukocyte marker CD45 were negative,which was consistent with the cell phenotype of hPDLSCs.Alizarin red-S staining after 21 days of osteogenic induction of hPDLSCs showed the formation of mineralized nodules,and oil red O staining after 28 days of adipogenic induction of hPDLSCs showed the accumulation of lipid droplets,indicating that cells have the potential of multi-directional differentiation.(2)The results of CCK-8 showed that sertraline had no significant effect on cell proliferation at the first day.On day 3 and 5,0.1 μmol/L sertraline promoted the proliferation of hPDLSCs(P<0.05),1 μmol/L and 10 μmol/L sertraline had no significant effect on the proliferation of hPDLSCs,but 100 μmol/L sertraline significantly inhibited cell proliferation.(3)According to the result of CCK-8 assays,0 μmol/L,0.1 μmol/L,1 μmol/L and 10μmol/L sertraline was selected for alizarin red-S staining and ALP activity test.The results showed that 0.1 μmol/L sertraline had no significant effect on mineralization and ALP activity of hPDLSCs,but 1 μmol/L and 10 μmol/L sertraline inhibited the formation of mineralized nodules and ALP activity(P<0.05).It was further supported by qRT-PCR and Western blot that 10μmol/L sertraline reduced the mRNA and protein expression of ALP,Runx2 and Osterix.Conclusion:1.Sertraline had no significant effect on orthodontic tooth movement and orthodontic induced root resorption in rats.2.Sertraline changed the bone trabecular structure of alveolar bone during orthodontic tooth movement and reduced the bone formation on the tension side of the orthodontic tooth.3.Sertraline could inhibit the osteogenic differentiation of hPDLSCs. |
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