Effects Of NDRG1 On The Expression Of COL-? And Smad3 In Human Gingival Fibroblasts Under Compression Force

Objective:(1)To investigate the effects of compression force on the expression of NDRG1 and Smad3 in human gingival fibroblasts(HGFs).(2)To investigate the effects of NDRG1 overexpression on the proliferative ability and the expression of Smad3 and COL-? in HGFs.Methods:1.Gravity loading model of HGFs was established by three-dimensional culture with PLGA scaffold technique.Four groups of HGFs-PLGA model were compressed by 25g/cm~2 force for 0 hour,12hours,24 hours and 48 hours respectively.The mRNA and protein expression level of NDRG1 and Smad3 at different time were measured by RT-q PCR and Western Blot;2.HGFs were contaminated with lentivirus to overexpress the NDRG1.The effect of NDRG1overexpression on cell proliferation was detected by CCK-8.The mRNA and protein expression levels of NDRG1 and Smad3 were investigated by RT-qPCR and Western Blot after overexpression of NDRG1.Results:(1)After applying of the 25g/cm~2 compression force to the HGFs on the PLGA scaffold,the mRNA and protein of NDRG1 were up-regulated at different time and reached the peak level at 24 hours.The difference of each group was statistically significant.(2)The mRNA expression level of Smad3 was decreased after force applying to 48 hours.Although there was no significant difference between the 24 hours group and 48 hours group,but the difference of all the other groups were statistically significant.The protein of Smad3 was decreased all the time after applying compression force and the difference of each group was statistically significant.(3)After lentivirus contamination,there was no difference in the proliferative ability of HGFs in each group on the first day.In the negative control group,the proliferation ability of cells showed a slightly continuous increase from the first to the fifth days,but they were all lower than the blank control group,and decreased sharply on the seventh day.On the third day,the proliferative ability of HGFs in the overexpressed NDRG1 group was significantly enhanced and continued to proliferate more than the negative control group,and increased as well as the blank control group since the fifth day.(4)The mRNA and protein expression of COL-? and Smad3 in the overexpression NDRG1 group was lower than those in the negative control group(P<0.05).The mRNA and protein expression of COL-? and Smad3 in the negative control group was higher than those in the blank control group(P<0.05).Conclusion:The 25g/cm~2 compression force increased the mRNA and protein expression level of NDRG1,and down-regulated the mRNA and protein expression level of Smad3 in HGFs.The proliferation of HGFs was enhanced and the mRNA and protein expression of Smad3 and COL-? in HGFs were inhibited after NDRG1 overexpression.It was suggested that in the process of compression applying to the HGFs NDRG1 could block the Smad3 signaling pathway and inhibit the synthesis of COL-? in HGFs,and could promote the proliferation of HGFs.It indicated that NDRG1 might play an important role in the remodeling process of gingival tissue under compression force.