Abstract
Abstract: :
Purpose: To evaluate the expression patterns of α2, α3, α5 & α6 integrin subunits in human posterior capsular opacification (PCO) comparing with their expression in mouse lens epithelial cells (LECs) during embryonic differentiation and wound-induced epithelial-mesenchymal transition (EMT). Methods:The animal protocol was approved by Wakayama Medical University. We employed the procedure approved by NCI/NIH. Lens anterior capsule in one eye of C57BL/6 mice (n=15) was broken with a hypodermic needle under both general and topic anesthesia and allowed to heal for specific intervals up to 2 months. Paraffin sections of healing, injured lenses and also for embryonic mice (n=110) eyes (E10.5-E18.5) were all processed for immunohistochemistry staining for α2, α3, α5 and α6 integrin subunits. Embryonic murine lens fiber cells were also examined by immune electron microscopy. Frozen sections of human PCO were similarly immunostained after informed consent was obtained. Results:Mouse embryonic LECs express α2, α3, α5, and, lately, α6 subunits. Embryonic mouse lens fiber cells express α2, α5, and α6 subunits. Mouse intact LECs express α3, and α6 subunits, while injury-induced fibroblast-like cells express α2, α3, and α6 subunits; interestingly, α5 subunit continued to be negative. Human PCO cells express α2, α3, α5, and α6 subunits. Conclusions:In mouse lens, fiber cell differentiation was characterized by the down-regulation of α3 subunit expression, while EMT was characterized by the up-regulation of α2 subunit. In human PCO, the expression of α2, α3, and α6 can be explained by the EMT phenomenon similar to the injured adult mouse lens, while the expression of α5 subunit can be explained also by EMT but in different species, or by fiber cell differentiation, since PCO represents both conditions.
Keywords: posterior capsular opacification (PCO) • wound healing • immunohistochemistry