Leila Roshangar - Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Jafar Soleimani Rad - Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Parisa Nikpou - Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Daryoush Mohammad Nejad - Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Background and Aim: The restricted regenerative ability of humancartilage imposed a drastic need for the applying stem cell relatedregenerative treatment. Adipose-tissue derived stem cells (ADSC) haveprovided promising potentials for supporting new clinical conceptsin cellular therapy. While it is still unclear if they can be implied forrepairing impaired cartilage cells. This study aimed to decipher thecellular and molecular differentiation of ADSCs co-cultured with maturechondrocytes.Methods: The adult ADSCs for chondrocyte differentiation wereobtained from the human intra-patellar fat pad and were seeded intopolycaprolactone scaffold following a co-culture system with maturechondrocytes. The control sample was prepared using ADSC cultured onscaffolds. After twenty-one days, differentiation of co-cultured sampleswas investigated and compared with control samples according tochondrogenic gene expression and microscopic features using Real-timeRT-PCR and transmission electron microscopy (TEM).Results: Based on the Real-time RT-PCR results, the co-cultured ASCsexpressed significantly lower chondrogenic differentiation marker of Indian hedgehog (IHH) compared with the control group (P = 0.004).However, the expression of other chondrogenic markers such as aggrecan(ACAN) and collagen type 2 didn t differ significantly between the twosamples. The images of TEM revealed stretched shaped co-cultured cellsas opposed to round formation of chondrocytes and control cells. Thenucleus of co-cultured cells occupied the majority of cell volume, whilethe nucleus proportion to cytoplasm was smaller in both control cells andchondrocytes. There were also some multi-laminar particles containingautophagic vacuole within the cytoplasm of both study samples, whichdidn t exist in normal chondrocytes.Conclusion: These study findings indicated that mature chondrocytesdidn t induce chondrogenic differentiation in human ADSCs.

Adipose-Derived Stem Cell; Chondrogenesis; Chondrocyte characteristics; Co-culture