At 7
days after implantation, cells double-positive for GFP and myoglobin and cells double-positive for GFP and SMA are present within the wound region as isolated cells that are not in physical contact with each other. In contrast, by 14 days the GFP and myoglobin double-positive cells are in contact with each other and with non-GFP expressing striated cells derived from uninjured surrounding tissues. Similarly, the GFP and SMA double-positive cells also contact each other and non-GFP expressing smooth muscle cells. The association of these cells forms higher order layered muscle structures within the urethral sphincters. MK-1775 research buy Furthermore, within the developing musculature, there are blood vessel walls containing smooth muscle cells that are double-positive for GFP and SMA. These results suggest that the striated muscle
and smooth muscle cells derived from implanted bone marrow-derived cells may advance the reconstruction of muscle tissues and vascular components to support them. At 7 days after cell implantation, a few of the GFP-labeled implanted cells are simultaneously positive for Pax7 (Fig. 4e), suggesting that they have myoblast properties. In the development process to mature muscle, Pax7 acts as transcription factor, and satellite cells and myoblasts both express Pax7, but mature muscle cells do not. Currently selleck inhibitor we cannot determine if the cells expressing both GFP and Pax7 are presumptive satellite cells or myoblasts. Nevertheless, the implanted cells clearly follow a development process that leads to the differentiation of striated or smooth muscle cells. The number of the cells expressing both GFP and Pax7 on day 14 is distinctly higher than on day
7 (Fig. 4f). Myoblasts properly differentiate into striated or smooth muscle cells according to surrounding environment.2 The greater number of Pax7 cells on day 14 compared to day 7 suggests that the formation rate of differentiated muscle cells may have decreased or even stopped. This suggests that the process of new striated and smooth muscle cell differentiation DOK2 is under some type of intrinsic regulation. Understanding the controls for differentiation of the implanted cells is very important for further development of regenerative medicine. While the details of this regulation are currently unknown, it is clear that the presence of the myoblasts in the regenerated region may have important long-term significance. In the event that the newly differentiated striated and/or smooth muscle tissues and structures spontaneously regress or are lost for other reasons, the presence of the myoblasts could ensure the replacement of the lost cells. Thus, the effects of treatments may be maintained for long periods of time. To develop regenerative medicine, we must investigate and provide various cell sources that are best suited to the health conditions and lifestyles of our patients.