292-LB: The Exercise-Like Impacts of Conditioned Media Harvested from Cultured Dental Pulp Stem Cells on Myokine Expressions in Skeletal Muscles

Exercise improves not only glycemic control, but also other metabolic disorders in diabetic patients. Furthermore, exercise also stimulate muscle-derived secreted factors, myokines, via muscle contraction. The receptors of myokines expressed in the whole body and myokines affect autocrine, paracrine, and systemic functions for all people and patients with diabetes. In this study, we have demonstrated that there are exercise-like impacts of conditioned media from cultured dental pulp stem cells (DPSCs) on myokine expressions in skeletal muscles. DPSCs were isolated and cultured from the mandibular incisors of 6-week-old male Sprague-Dawley (SD) rats. Conditioned media from DPSCs (DPSC-CM) was collected after 24-hour culture of DPSCs in the serum-free medium and concentrated by a factor of 10. We firstly investigated the effects of DPSC-CM on exercise-induced myokines, follistatin-like 1 (Fstl1), Fractalkine, and fibroblast growth factor 21 (FGF-21) in C2C12 myotubes. DPSC-CM significantly increased the gene expressions of Fstl1 (209±16%, P<0.01), Fractalkine(182±41%, P<0.05), and FGF-21 (1021±39%, P<0.01) in C2C12 myotubes. To confirm these effects in vivo, we administered DPSC-CM (1.0 ml/rat) into 10 sites of unilateral hindlimb skeletal muscles of male SD rats, and examined the effects on myokine gene and protein expression. DPSC-CM significantly increased Fstl1 gene expression in the gastrocnemius muscles (477±140%, P<0.05). Immunohistochemical staining revealed that the expression of Fstl1 was increased in the DPSC-CM-injected gastrocnemius muscles. These results suggest that there is a novel exercise-like impact of DPSC-CM on skeletal muscles.