Purpose: To evaluate the role of macrophages in the development of posterior capsule opacification (PCO).
Methods: For this purpose, an extracapsular lens extraction was performed in 18 consecutive Sprague-Dawley rats. Animals were treated with liposomal clodronate (Cl2MDP-lip-treated group, n=10) or phosphate-buffered saline (control group, n=8) one day preoperatively and on the first day postoperatively, and sacrificed 3 days postoperatively. Masked clinical, light microscopy and immunohistochemistry studies were conducted. Fisher’s exact test and randomization test were used to assess statistically differences between groups.
Results: A statistically significant reduction in the number of macrophages (ED1+, ED7+, ED8+) was found in the Cl2MDP-lip-treated group compared with the PBS-lip-treated group (p = 0.048, p = 0.004, p = 0.027, respectively). There were no statistically significant differences with regards to the presence/absence of central opacification (p = 0.29) and capsular wrinkling (p = 0.21) as detected clinically between groups. Similarly, a qualitative evaluation of the degree of PCO with regards to lens epithelial cell (LEC) proliferation, capsular wrinkling and Soemmerring's ring formation showed no statistically significance between groups (p= 0.27, p= 0.061, p = 1.0, respectively). However, a statistically significant reduction in the number of lens epithelial cells (LEC) counted in the center of the posterior capsule was found in the Cl2MDP-lip-treated group (p= 0.009).
Conclusion: Depletion of macrophages was accompanied by a reduction in LEC in the center of the posterior capsule in rodents.