Fig. 4. DRG neurons enhance the osteoblast differentiation ability of MSCs.

Sensory neurons derived from rat DRG (5 × 10⁴ cells/cm²) and rat bone marrow MSCs (10⁴ cells/cm²) were cocultured in microfluidic devices for 7 days. DRG neurons were maintained in DMEM supplemented with 2% (v/v) B-27 and 1 μM AraC; MSCs were incubated in OIM composed of DMEM-low glucose with 10% (v/v) FBS, 1 × 10⁻⁹ M dexamethasone, 10 mM β-glycerophosphate, and 50 μg/mL ascorbic acid. a–d Expression profile of Runx2, Sp7, Col1a1, and Bglap in MSCs was assessed at 4 and 7 days of coculture by RT-qPCR and depicted as a relative ratio to the housekeeping gene Hprt1 normalized to the monoculture levels on day 4. e and f Alp activity in MSCs was analyzed at 4 and 7 days of coculture by Alp activity quantification assay and cytochemical staining. Scale bar = 300 µm. Data expressed as mean ± SD. (n) indicates the total number of samples for each group. *p < 0.05; **p < 0.01 statistically different from monoculture. The results represent three independent experiments.