Abstract
Purpose::
The iridocorneal angle, including the trabecular meshwork (TM), forms in the mammalian eye from undifferentiated mesenchyme between the root of iris and cornea. The precise mechanisms underlying the angle development are still unclear, and participation of cellular death and phagocytic resorption with macrophages in angle development is controversial. In this study, their involvement in the development of the chamber angle in human eyes was examined.
Methods::
Eyes from human fetus (F) of 8, 15, 18, 22 and 27 weeks (w), as well as eyes from 5 and 11-month (m)-old children and donors 24, 48 and 67 years (y) of age were obtained from the University of Seattle tissue bank, University of Illinois at Chicago, Illinois Eye Bank and National Disease Research Interchange. Formalin-fixed and paraffin-embedded sections were examined by hematoxylin & eosin (H&E) staining. Immunohistochemistry was performed using polyclonal antibodies against CD68 (macrophage marker). TUNEL labeling was also carried out to evaluate cell death.
Results::
None of the chamber angle tissues stained for CD68 at any stages. A few CD68 positive cells were observed in the iris stroma and the ciliary body, where monocytes were noted on H&E staining, from F27w to 11m. TUNEL labeled nuclei were not detected in the anterior chamber angle in all fetal and infant eyes. By contrast, TUNEL positive nuclei in TM cells were found in adult specimens examined. The size of TUNEL positive cells was similar or smaller than other TM cells.
Conclusions::
The results suggest that, at the time points examined, neither cell death nor phagocytic resorption with macrophages appear to play a role in the development of the human anterior chamber angle.
Keywords: trabecular meshwork • development • immunohistochemistry