Autonomic Response of the Iris Induces Vascular Apoptosis During Lens Development in the Rat Eye

Abstract

Abstract: : Purpose: Autonomic response of the iris, pupillary constriction and dilation, regulates the level of light transmission into the eye. In the developing mammalian lens, the pupillary membrane (PM) is a transient capillary meshwork that regresses in rats by day 14 after birth (P14). Here we hypothesized that the iris’s autonomic response induces the PM regression, based on our preliminary finding that the development of autonomic responsiveness in the iris preceded regression of the PM. Methods: The effects of iris’s autonomic response on the PM blood flow dynamics were evaluated in vivo. After controlling autonomic response of the iris via instillation of eye drops as follows, the number of vessels and apoptotic cells were evaluated at P12 (n = 10): (1) Control group: saline, (2) Inhibition of iris’s autonomic response group: 1% atropine sulphate (every 4 hours). Results: Iris’s autonomic response caused cessation and resumption of flow within the PM. Continuous inhibition of the iris’s autonomic response resulted in larger number of the vessels and lower percentage of apoptotic cells (0.6 ± 0.2%) than control (4.4 ± 0.6%, p < 0.001). Conclusions: Iris’s autonomic response induces the PM regression via cessation and resumption of flow within the PM.

Keywords: apoptosis/cell death • pupil • ischemia