Establishment of an improved model of posterior capsule opacification in rats and dynamic observation of LEC

• Aim: To establish an animal model of posterior capsule opacification (PCO) in rats by an improved surgical procedure and to observe the dynamic changes of lens epithelial cells (LEC) during the development of PCO. • Methods: An extracapsular lens extraction (ECLE), after continuous curvilinear capsulorrhexis and hydrodissection, was performed in 50SD rats. Bacteria-free air was used to fill and maintain the anterior chamber after the lens was removed. Animals were observed by slit-lamp microscope at 0 hour and 3, 7, 14 and 28 days after the surgery, and were killed at these time points. The eyeballs were enucleated for light microscopy. The transdifferentiation of the LEC was indicated by the detection of alpha-smooth muscle actin (α-SMA) through immunohistochemistry. • Results: All of the posterior capsules were integrate after ECLE, and 84% operated eyes recovered well and could be used to detect. The lens epithelial cells (LEC) could be seen in the inner surface of equator and under the anterior capsule. At 3 days after the surgery, PCO began to occur, and spindle shaped cells were present throughout the lens capsule. Capsular wrinkling was apparent. At 7 days the PCO was obvious and several fibrocytes migrated to the posterior capsule. Capsular wrinkling could be found at 14 days after the surgery in all the animals, and lens fiber could be observed under the light microscope. At 28 days after the surgery the thickness of posterior capsule increased obviously and the regenerated lens fiber filled the capsular bag. Cells were no longer found in the posterior capsule. The form and distribution of LECs recovered to those of 0 hour after the surgery. At 3 days after surgery α-SMA was found positive expression in the LEC of posterior capsule. • Conclusion: The PCO animal model can be established successfully in rats by an improved surgical procedure. The dynamic changes of LEC can be found during the development of PCO. It is a proper model for the investigation of the pathogenesis, prevention and treatment of PCO on molecular level.