The rate of ES-D3 cell differentiation into cardiomyocytes is an important factor in the embryo stem cell tests (EST) protocol for the screening of embryotoxicity. We investigated the effects of dental Ag-In alloys on ES-D3 cells by adding artificial saliva.

In the present study, we used Greenwood-prescribed artificial saliva and clinical artificial saliva (Saliveht^®) to examine the effect of saliva on the differentiation of ES-D3 cells that are commonly used in EST protocol.

We demonstrated that the two artificial types of saliva affected the differentiation of ES-D3 cells when added to the culture medium at 10% of the total volume. We examined the effect of indium on ES-D3 cell differentiation in a collagen-based 3D cell culture system. To do this, we prepared Ag-In alloys with 10, 15, and 20% indium as well as its powdered acid corrosion product and added them to a culture medium that contained artificial saliva at 10% of the total volume. We demonstrated that while cells differentiated at a relatively low level when cultured with an Ag-In alloy that had not been exposed to acid, cells did not differentiate when cultured with the acid corrosion product of the alloy. These findings suggest that the composition of a culture medium has a significant effect on cell differentiation.

Osteoarthritis is a long-term chronic joint disease and the single most common cause of disability in older adults due to deterioration of articular cartilage. At the cellular level, it is characterized by a decreased expression of cartilage matrix proteins, an increase in cartilage-degrading enzymes and inflammatory markers and cell death. Several mouse or rat in vivo models are routinely used to study osteoarthritis such as the destabilization of the medial meniscus (DMM) model, which alters the joint mechanics. However, there are still very few in vitro tools to study mechanically-induced chondrocyte damage. Here, we used cells from the ATDC5 chondrocyte progenitor cell line and differentiated them into chondrocyte aggregates by seven days of rotation culture; after differentiation, the aggregates were dissociated and the obtained cells were seeded onto Petri dishes to form monolayers; the high chondrocyte marker gene expressions were maintained on the Petri dishes for at least three days; submitting these monolayers to high hydrostatic pressure then led to a rapid down-regulation of chondrocyte marker expression. Such an in vitro cell culture protocol may be useful to study mechanically-induced chondrocyte damage without the need for conventional animal models.