A Study for the Biologic Changes and Viability of Adipose Tissue in Cryopreserved Fat Graft

ABSTRACT

PURPOSE: Adipose tissue injection as a free graft for the correction of soft-tissue deficiency or depression deformity is a widespread procedure in plastic surgery. This study is to analyze the changes and viability of cryopreserved adipose tissue and to find out efficient long-term storage period. METHODS: After centrifugation of aspirated abdominal tissues, 10mL of packed Adipose tissue were freezed at -20degrees C. For 2, 4, 6, 8 months, each frozen samples were taken and injected into scalp of SCID mice. After 15 weeks, injected Adipose tissue were sampled and analyzed at 2 months interval. We compared and analyzed each group about the weight of the injected fat, histologic impressions, activity of mitochondria, size of a fat cell and rate of survival. RESULTS: Significant weight changes were observed in cryopreservation for 2 months(p<0.05). Histologic changes were observed, independent of the freezing period with H-E stain. Among cryopreservations for 2, 4, 6 months, no significant change were observed. The reduction of mitochondrial enzymatic activity was observed independent of time interval but activity of mitochondrial dehydrogenase was reduced less than 50% in MTT assay. CONCLUSION: Freezing at -20degrees C for 6 months has no adverse effect to Adipose tissue, but fragile adipocytes, damaged cell membrane during harvesting procedure, were disrupted within 1-2 month and the maximum volume reduction were followed less than 2 months. These results demonstrate that tissue preparation cells without membrane damage have the greatest viability level and cryopreservation less than 2 months has great volume effect and cryopreservation for 6 months has stable volume effect.