OCLN and Alzheimer disease: Moreover, tight junction proteins ZO-1 and Occludin were significantly disrupted in the AD group: the ZO-1-positive area decreased from 27.57 ± 5.04% in WT mice to 2.51 ± 0.89%, and Occludin from 39.72 ± 5.64% to 8.46 ± 2.8%.