[Experimental study on the best concentration of SVFs for promoting survival rate of fat graft]

To investigate the effect of different concentrations of human adipose stromal vascular fraction cells (SVFs) on the survival rate of fat transplantation.

0.3 ml fat tissue, derived and refined from clinical liposuction patients, was mixed with different concentrations of SVFs as 5 x 10(5)/ml in Group A, or 1 x 10(6)/ml in Group B, or 2 x 10(6)/ml in Group C, or completely medium in control group D. Then the mixture was injected randomly under the back skin of 6 nude mice. The transplanted fat tissue in four groups was harvested at 3 months after implantation. Wet weight of fat grafts was measured for macroscopic aspects. After HE staining, blood vessel density, viable adipocytes and fibrous proliferation were counted respectively for histological evaluation.

The wet weight of fat grafts in group B (81.670 +/- 7.528) mg was significantly higher than that in group A, C, D [(60.000 +/- 6.325) mg, (68.330 +/- 7.528) mg, (48.330 +/- 7.528) mg, respectively, P < 0.05)], but the difference between group A and group C was not statistically significant (P > 0.05). The grafts in group A, B and C had significantly higher blood vessel density than those in the control group D, whereas blood vessel density was the highest in group B (P < 0.05) and there was no significant difference between group A and C (P > 0.05). Compared with group A, C and D, histological analysis revealed that the fat grafts in group B was consisted predominantly of adipose tissue with less fat necrosis and fibrosis (P < 0.05). However, fibrosis counts were significant lower in group A, B and C than those in group D (P < 0.05), and there was no significant difference between group A and C (P > 0.05).

The human isolated SVFs has the advantages to improve the survival rate of fat transplantation, and the magnitude of 1 x 10(6)/ml is more practical and safe, indicating a wide clinical application in the future.