Browsing by Subject "Embryonic development"

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    Presence of pigment in the ovine pineal gland during embryonic development
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Regodón, S.; Franco, A. J.; Gazquez, A.; Redondo, E.
    Light- and electron-mi croscopi c analyses were used 10 id entify and desc ribe th e charac teristi c features of cells containing pigment in the ov ine pineal gland during prenatal deve lopment. 72 ov ine embryos (36 male, 36 female) ranging in age from 54 to 150 days were used fo r this study. Ce lls co nt aining pigment granules were a constant fea ture in this gland . Wh en samples from the di f'ferent groups were inspected using the naked eye, the detection of pigment was of 61 % in groups I (54 to 67 days of prenatal development) and II (7 1 to 92 days of prenatal development), ~3 % in group III (9t; to 113 days of prenatal development) and 25% in gro up IV (II R to 150 days of prenatal deve lopment). The morphologica l featu res and histochemical properties of the pineal pigment enab led it to be identified as me lanin . Several types o f pigme nt granules were ultrastru cturall y distinguished; th ese varied in size, shape and loca tion within pinea l cell populations. The pigment g ranul es were de tec ted in pine alocy te s, interstitial cells and pigmented ce lls. The largest amount and the widest variety of pigmented granules were found in pigment ed ce lls. The prese nce of cells containing pigmented gra nules amongst the cell populations of the developing ov in e pineal gland was a nal ysed a nd compared with that of other mammalian species.
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    Wnt5a regulates the expression of developmental genes in the adult retina following optic nerve crush injury
    (Universidad de Murcia, Departamento de Histología e Histopatología, 2025) Albano Gabrielle A.; Parrales Paola E.; Hackam Abigail S.; Biología Celular e Histología
    Canonical and non-canonical Wnt signaling pathways are well-characterized regulators of retinal development. Wnt signaling also promotes neuro-protection and regeneration in adult tissues, including retinal ganglion cell (RGC) survival and axonal regrowth after optic nerve injury. However, it is unknown whether Wnt-dependent neuroprotection after injury in the adult CNS is associated with altered expression of developmental genes. Müller glia are a prominent radial glia type in the retina that play critical roles in retinal neuron protection, RGC neurite growth, and axon regeneration by acting through Wnt and other signaling pathways. We recently used mass spectrometry to characterize proteins secreted from Müller glia in response to Wnt signaling. In this study, we investigated whether the Wnt-induced Müller glia secretome includes proteins involved in development and whether their corresponding genes are regulated by Wnt5a during axonal regeneration in a mouse model of optic nerve crush (ONC) injury. Adult mice received intravitreal injections of Wnt5a or saline at the time of ONC injury, and then retina tissue was collected at early time points post-injury. The expression of candidate Wnt-regulated developmental genes and related proteins were characterized by qPCR and immunohistochemistry. Our findings revealed that Wnt5a downregulated the expression of specific developmental genes, including cilia-related genes Nphp4, INTU, and Jade1, as well as transcriptional regulators Pax6 and Tsc1, with time-dependent changes observed during axonal regrowth. Several of these genes were localized to RGCs and inner nuclear layer cells, suggesting direct effects in RGCs and contributions from Müller glia. These results demonstrate that specific developmental gene pathways are suppressed by Wnt5a in association with RGC survival and axon regrowth following injury. Therefore, this study adds to our knowledge of potential mechanisms of Wnt-mediated optic nerve regeneration and identifies new categories of putative regeneration-regulating genes for further study