Abstract: To be used in regenerative medicine, cells should be checked for various conditions, including cell aging. This study aimed to learn senescent profile and its relation to cell viability, proliferation and cell size in various passages, which were done in ?-MEM-10% PRP medium, until senescenceassociated ?-galactosidase (SA-?-Gal) positive cells were found. Stem cells were isolated from umbilical cord tissue by multiple harvest explant method, cultured in ?-MEM-10% PRP until P-17 and stained using SA-?-Gal staining. Viability, Population Doubling Time (PDT), percentage SA-?-Gal (+) and cell size at 30% confluent and at senescent staining were analyzed. Passages with SA-?-Gal (+) and (-) were compared in term of viability, PDT and cell size at 30% confluent. Further, cell size at senescent staining between SA-?-Gal (+) and (-) groups were compared.

Viability and PDT showed no significant difference between SA-?-Gal (+) and (-) groups, while cell size at 30% confluence showed significant increase in SA-?-Gal (+) compared to (-) groups. Further, cell size in senescent staining showed significantly smaller cell size in SA-?-Gal (-) compared to SA-?-Gal (+) cells. Moreover, this study showed that even in SA-?-Gal (+) group, viability was greater than 91%, PDT was less than 2.1 days and cell size was less than 2602 ?m2.

In conclusion, umbilical cord derived MSCs that were cultured in ?-MEM-10% PRP began to undergo aging at P-10. Morphological criteria of UC-MSC aging were cell size greater than 2602 ?m2 with a change in morphology toward a rounded shape. Keywords: Aging, Stem Cell, Umbilical Cord, Platelet Rich Plasma, Senescence