OBJECTIVETo investigate the effect of catalase (CAT) on engraftment of human hematopoietic stem cells (HSC) by co-transplanting umbilical cord-derived mesenchymal stem cells (UC-MSC) with over-expressed CAT and human HSC into NOD/SCID mice.

METHODSThe UC-MSC cultured in vitro were transfected by the retrovirus containing green fluorescent protein (GFP) and GFP-CAT genes respectively. MSC-GFP and MSC-GFP-CAT cell lines were sorted by flow cytometry. Co-culture and co-transplant experiments were performed to detect the effects of CAT on expansion and engraftment of human HSC.

RESULTSThe percentage of GFP(+) cells were approximately 97.6% and 96.8% after sorting. The mRNA expression of CAT in MSC-GFP-CAT was 23.9-fold higher than that in UC-MSC. The activity of CAT in UC-MSC, MSC-GFP, MSC-GFP-CAT cells were 19.5, 20.3 and 74.1 Unit respectively. There was no significant differences in the percentage of CD34(+) cells between 3 groups in co-culture experiment. And the percentage of human CD45(+) cells in NOD/SCID mice were (3.22 ± 3.1)%, (4.26 ± 3.56)% and (7.37 ± 4.51)% respectively.

CONCLUSIONMSC-GFP-CAT significantly improves the engraftment of human HSC in NOD/SCID mice, whereas co-culture with the MSC-GFP-CAT can not promote the expansion of HSC in vitro.