Nardin Patrícia, Tramontina Francine, Leite Marina C, Tramontina Ana Carolina, Quincozes-Santos André, de Almeida Lucia Maria Vieira, Battastini Ana Maria, Gottfried Carmem, Gonçalves Carlos-Alberto
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, 90035-003 Porto Alegre, RS, Brazil.
Neurochem Int. 2007 Apr;50(5):774-82. doi: 10.1016/j.neuint.2007.01.013. Epub 2007 Feb 9.
S100B is an astrocyte calcium-binding protein that plays a regulatory role in the cytoskeleton and cell cycle. Moreover, extracellular S100B, a marker of glial activation in several conditions of brain injury, has a trophic or apoptotic effect on neurons, depending on its concentration. Hyperglycemic rats show changes in glial parameters, including S100B expression. Here, we investigated cell density, morphological and biochemical alterations in primary cortical astrocytes from rats and C6 glioma cells cultured in high-glucose medium. Astrocytes and C6 glioma cells have a reduced content of S100B and glial fibrillary acidic protein when cultured in a high-glucose environment, as well as a reduced content of glutathione and cell proliferation rate. Although these cells have been used indistinctly to study S100B secretion, we observed a contrasting profile of S100B secretion in a high-glucose medium: a decrease in primary astrocytes and an increase in C6 glioma cells. Based on the in vitro neurotrophic effects of the S100B protein, our data suggest that chronic elevated glucose levels affect astrocyte activity, reducing extracellular secretion of S100B and that this, in turn, could affect neuronal activity and survival. Such astrocyte alterations could contribute to cognitive deficit and other impairments observed in diabetic patients.
S100B是一种星形胶质细胞钙结合蛋白，在细胞骨架和细胞周期中发挥调节作用。此外，细胞外S100B是几种脑损伤情况下神经胶质激活的标志物，根据其浓度不同，对神经元具有营养或凋亡作用。高血糖大鼠表现出神经胶质参数的变化，包括S100B表达的变化。在此，我们研究了在高糖培养基中培养的大鼠原代皮质星形胶质细胞和C6胶质瘤细胞的细胞密度、形态和生化改变。当在高糖环境中培养时，星形胶质细胞和C6胶质瘤细胞的S100B和胶质纤维酸性蛋白含量降低，同时谷胱甘肽含量和细胞增殖率也降低。尽管这些细胞在研究S100B分泌时被不加区分地使用，但我们观察到在高糖培养基中S100B分泌呈现出相反的情况：原代星形胶质细胞中S100B分泌减少，而C6胶质瘤细胞中S100B分泌增加。基于S100B蛋白的体外神经营养作用，我们的数据表明，长期升高的葡萄糖水平会影响星形胶质细胞的活性，减少S100B的细胞外分泌，而这反过来可能会影响神经元的活性和存活。这种星形胶质细胞的改变可能导致糖尿病患者出现认知缺陷和其他损伤。
