Objective      To determine the effect of secretory leukocyte protease inhibitor (SLPI) on promoting proliferation of dermal multipotent stem cells (DMSCs).       Methods      DMSCs were isolated from neonatal rats by enzyme digestion

and then purified and amplified for further research. Based on successful construction of SLPI o

verexpression vector

SLPI gene siRNA expression vector was picked out according to RT-PCR and Western blot identification. DMSCs were transformed with recombinant expression plasmids of SLPI gene

and the effect of SPLI gene on promoting the proliferation of DMSCs was observed using CCK-8 assay and flow cytometry.       Results      DMSCs were successfully isolated from the dermis. The eukaryotic expression vector and siRNA expression vector of SLPI gene were constructed. The transformed DMSCs were divided into 3 groups: overexpression group

interference group

and control group (transformation with blank vector). The results of CCK-8 assay showed that

in 48

72 h and 96 h after transformation

the proliferation of DMSCs in the overexpression group was faster than that in the interference group (P0.05)

and in 72 and 96 h after transformation

DMSCs in the overexpression group were significantly different from those in the control group (P0.05)

which suggested that SLPI gene might promote the proliferation of DMSCs. The results of flow cytometry showed that the cells in the G

1

phase in the overexpression group were significantly different from those in the interference group (P0.05)

meanwhile

the cells in the S phase and G

2

phase were significantly different from those in the control group (P0.05).       Conclusion      SLPI gene plays a role in promoting the proliferation of DMSCs

and promotes cell cycle transformation from G

1

phase to S phase and G

2

phase

which suggests that SLPI may promote proliferation of DMSCs via regulating cell cycle.