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Background: Thyroid hormones have many effects on the physiological functions of cells, including growth, differentiation, and metabolism. Objectives: Recently, studies have shown that the adipose-derived mesenchymal stem cells conditioned medium (ADMSCs-CM) has many osteogenic factors, such as IGF-1, IL-6, and FGFs. Methods: In the current study, mesenchymal stem cells (MSCs) were isolated from two sources; the adipose tissue of the testicular fat pad and the bone marrow of rat, and then characterized by flow cytometry. ADMSCs-CM was collected from the ADMSC in the healthy adult male rats. Hypothyroidism was induced by the administration of the Methimazole during 60 days and confirmed by the analysis of the serum level of T4 and TSH hormones. Cell proliferation and osteogenic differentiation potential of bone marrow stem cells (BMSCs) derived from hypothyroid rats were investigated in the presence and absence of the CM by MTT assay, alkaline phosphatase (ALP) activity, calcium content assay, and bone-related gene expression. Healthy BMSCs were assigned to the control group. Results: Although Cell proliferation was decreased in the hypothyroid BMSCs, there was no significant difference between the control and the hypothyroid-CM groups. Similarly, osteogenic potential was significantly reduced in the hypothyroid group compared to the control and hypothyroid-CM groups according to the ALP, calcium content assays, and gene expression results. There was no significant difference between the hypothyroid-CM group and control. Conclusions: Our results indicated that hypothyroidism can decrease cell proliferation and osteogenic differentiation of BMSCs. Although ADMSCs-CM improved these parameters, it may be a promising candidate for the bone regeneration of the hypothyroidism cases.

Background and Aims: The current study was conducted to compare the expression levels of collagen type Π and X during chondrogenesis of human adipose-derived mesenchymal stem cells (hADMSCs) pellet and micromass cultures.  Materials and Methods: Extracted hADMSCs were cultured until three passages and then transferred to pellet and micromass cultures in the experimental groups of day 7 and day14. For pellet and micromass cultures, aliquots of 5×105 cells/ml were centrifuged and respectively cultured in the conical tubes and droplets (12.5 µl) of the 24-well plates containing  chondrogenic medium. Realtime-polymerase chain reaction technique was performed for gene expression levels. Results: Increased expression of collagen type Π was shown in micromass day14 compared to micromass day 7, pellet day 14 (p<0.01) and pellet day 7 (p<0.001). Also, an increased expression of collagen type Π was seen in micromass day 7 and pellet day 14 compared to pellet day 7 (p< 0.05). Expression of collagen type X increased in pellet day 14 compared to micromass on days 7 and 14 (p<0.001, p<0.01) and pellet day14 compared to pellet day7 (p< 0.05). An increased expression of collagen type X was shown in pellet day 7 compared to micromass on days 7 and 14 (p<0.05). Conclusions: According to the results, higher expression of collagen type Π and lower expression of collagen type X in micromass cultures that are prepared by cell suspension play a better role during cellular condensation that leads to the formation of large nodules exhibiting cartilage-like morphology, suggests a higher efficiency for micromass cultures.

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