3.2.3 Reduced expression of TJ proteins
Using electron microscopic analysis, Garbuzova-Davis et al.suggested that the endothelial cell TJs appeared intact in early and late symptomatic SOD1G93A mice (Garbuzova-Davis, Haller, Saporta, Kolomey, Nicosia & Sanberg, 2007). However, using a more quantitative approach (Western blot), a 30-60% reduction in zonula occludens-1, occludin and claudin-5 was consistently observed in spinal cord microvessels of SOD1G93A mice relative to wildtype mice (Zhong et al., 2008). In addition, a progressive reduction in occludin abundance at the BSCB in SOD1G93A mice was demonstrated by Miyazaki et al. using immunohistochemistry and Western blot (Miyazaki et al., 2011). Similarly, in SOD1G93A rats, zonula occludens-1 and occludin mRNA were significantly reduced in the lumbar spinal cords at the symptomatic stage only but not in the brain or brain stem (Nicaise et al., 2009).