Objective To investigate the effect of osteoblastspecific factor 2 (OSF2

Periostin) on keloid mesenchymal stem cells（KMLSCs）growth in vitro through nude mice model. Methods KMLSCs was isolated from keloid.The experiments were divided into three groups:the Periostin group

the blankvector group and the nontransfected group. The Periostin lentiviral vector were constructed and infected into the corresponding KMLSCs. The expression of Periostin

alpha smooth muscle actin (α-SMA)

and vascular endothelial growth factor(VEGF) were determined in vitro by Western blotting.Chitosansilk fibroin porpous scaffolds were made through freeze drying.The KMLSCs were cocultured with the scaffolds

and the cellscaffolds and the growth of cells were detected by scanning electron microscopy.The cellscaffold complexes were subcutaneously implanted into the nude mices.After 8 weeeks the mices were killed to measure the volume of the keloid.The expression of Periostin

αSMA

and VEGF in keloid were detected by immunofluorescent staining

and the expression of Erk was detected by Western blotting. Results In the blankvector group and the nontransfected group

the Periostin were expressed normally in KMLSCs

but it was Weakly expressed in the Periostin group.And the αSMA and VEGF were not expressed in KMLSCs cultured in vitro.The cells grew well on composite scaffolds.Tumor transplantation models of different groups survived well subcutaneously in vivo in nude mice.However

when the expression of Periostin were downregulated

the volume of keloid was statistically smaller(P<0.05)

and the expression of αSMA

VEGF and Erk siginificantly attenuated(P<0.05). Conclusion Periostin can regulate the functions of KMLSCs in vivo and promote the growth of keloid in nude mice.