| Skin is distributed widely in the surface of mammal and human. There are a lot of superficial nerve captors and nerve terminals in the basal lamina of epidermis. By development neurobiology., it is indicated that skin and gangliocytes were traceable from ectoderm, the peripheral processes of dorsal root ganglioncytes extended to the specific layers of skin in embryonic development period, form coarctate neural network, it is demonstrated that there is a certain close relationship between the development of skin and the development of sensory fibers of peripheral nerve. However, when and how the cells of skin start to set up the connection with the nerve terminals, What induce nerve terminals growing to the target regions and what participate in adjusting, These questions are not clear.NO (nitric oxide) is a messenger molecule which has an intra-cellular and inter-cellular intense activity. NO distributes generally in many tissues of biosystem, esperially in the nerve tissue. There are many study reports about the characteristics of distribution of NO in the central nervous system and in the peripheral nervous system. However, it is not reported about the distribution and development of peripheral nervous terminals in the embryonic period of mice.Therefore, we injected FG (fluorogold) and HRP (horse radish peroxidase;horseradish peroxidase) into amniotic fluid in rats for retrograde tracing, observing whether FG or HRP will appear in somatic nerves and dorsal root ganglion cells of fetal. In addition, we tend to research the distribution and development of nitric oxide synthase positive nerve terminals of skin in the embryonic period of mice by NADPH-d enzymohistochemistry method and immunohistochemical method.Materials and Methods1. HRP and FG was injected into amniotic fluid in rats with 13- 15d pregnancy in vivo, observing whether they have FG or HRP in somatic nerves and dorsal root ganglion cells of fetal by light microscope. Slices of HRP were stained by H2O2-TMP.2. The skin tissue of Ell(Embryo day 11), E13, E15, E17, E19, E21(P0) and PI (Postnatal day 1) mice embryos were taken out, the freeze sections of each group acral skin tissues were stained with NADPH-d enzymohistochemistry method and immunohistochemical method, to localize the expression of nNOS.Results1. In the spinal nerves of fetal, some HRP or FG positive neural cells were observed, mainly in arborization or intestiniform. In the spinal nerves or somatic nerves of fetal, some round or irregular neural cells by HRP or FG labeled were observed. FG mainly in the cell body, with even and bright in the kytoplasm, and the boundary was clear. While HRP green color response mainly distributed in the kytoplasm and tubercle.2. NOS positive nerve terminals can be seen in El 1, and increaseinged graudally with age. The expression in E21 (P0) was similar to this of postnatal. It mainly expressed on the surface or in the cuticular layer, and rare in the dermis or subcutaneous.Conclusions1. Skin sets up a relationship with dorsal root ganglion cells when it differentiates mature.2. The expression of NOS in the skin tissue during embryo development stage iscorrelate with the development of nerve terminals, and it may be involved in the maturational mechanisms of neural cell such as the organization of its migration, proliferation and differentiation processes, and may have the effects on neuronal protection as well as axonal growth promotion.3. In the embryonic period, the amniotic fluid may be in touch with the skin of fetal, so the amniotic fluid may take part in the growth and development of nerve terminals of fetal. The substance in amniotic fluid may have the effect of inducing growth on the development of ganglion cells. |
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