Erlich Rafael B, Werneck Cláudio C, Mourão Paulo A S, Linden Rafael
Instituto de Biofísica da UFRJ, Rio de Janeiro, RJ, Brazil.
Exp Eye Res. 2003 Aug;77(2):157-65. doi: 10.1016/s0014-4835(03)00129-5.
Retinal explants maintained in culture medium retain their histotypic structure and develop similarly to the in vivo condition. Extracellular matrix components, particularly the glycosaminoglycans which are not routinely present in dissociated cell cultures are involved in various cellular events. In this work we characterized and determined the localization of sulfated glycosaminoglycans in the extracellular matrix of rat retinal explants at various stages of normal postnatal development and tested whether disruption of the tissue glycosaminoglycan composition may impose either trophic or toxic effects upon distinct retinal cell populations. Our data show that chondroitin sulfate and heparan sulfate glycosaminoglycan chains are synthesized in different proportions during postnatal retinal development. A peak of synthesis of chondroitin sulfates is evident at around P14. Immunohistochemistry showed chondroitin 6-sulfate in the plexiform layers during the earlier stages while later, intense immunoreactivity was found in the outer retina. Heparan sulfate was found in the neuroblastic layer (NBL) at P1, in both nuclear layers from P5 onwards and in the ganglion cell layer (GCL) at all stages. In contrast to chondroitin 6-sulfate, immunoreactivity to heparan sulfate was absent from the outer retina at both P14 and P21. Treatment with heparitinase modulated the rates of cell death in both the GCL and the NBL in P1 retinal explants. Taken together our data show that among the major sulfated glycosaminoglycans, the developing rat retina synthesizes only heparan sulfate and chondroitin sulfates in a spatiotemporally regulated manner, with a peak of chondroitin sulfates at P14, possibly related to photoreceptor differentiation. In addition, our data suggest a role for heparan sulfate as a modulator of sensitivity to cell death in the retina.
维持在培养基中的视网膜外植体保留其组织型结构，并与体内情况相似地发育。细胞外基质成分，特别是在解离细胞培养中通常不存在的糖胺聚糖，参与各种细胞事件。在这项工作中，我们表征并确定了硫酸化糖胺聚糖在正常出生后发育各阶段大鼠视网膜外植体细胞外基质中的定位，并测试了组织糖胺聚糖组成的破坏是否可能对不同的视网膜细胞群体施加营养或毒性作用。我们的数据表明，硫酸软骨素和硫酸乙酰肝素糖胺聚糖链在出生后视网膜发育过程中以不同比例合成。硫酸软骨素的合成高峰在出生后第14天左右明显。免疫组织化学显示，早期阶段在神经纤维层有硫酸软骨素6 - 硫酸酯，而后期在外视网膜发现强烈的免疫反应性。硫酸乙酰肝素在出生后第1天存在于神经母细胞层（NBL），从出生后第5天起在两个核层中存在，并且在所有阶段的神经节细胞层（GCL）中都存在。与硫酸软骨素6 - 硫酸酯相反，在出生后第14天和第21天，外视网膜均不存在对硫酸乙酰肝素的免疫反应性。用硫酸乙酰肝素酶处理可调节出生后第1天视网膜外植体中神经节细胞层和神经母细胞层的细胞死亡率。综上所述，我们的数据表明，在主要的硫酸化糖胺聚糖中，发育中的大鼠视网膜仅以时空调节的方式合成硫酸乙酰肝素和硫酸软骨素，硫酸软骨素在出生后第14天达到高峰，这可能与光感受器分化有关。此外，我们的数据表明硫酸乙酰肝素作为视网膜细胞死亡敏感性调节剂的作用。
