Transmission electron microscopy of the rabbit posterior capsule irrigated with thapsigargin and 5-fluorouracil in a sealed-capsule irrigation device.

Purpose: To investigate, by transmission electron microscopy (TEM), the effect on the posterior capsule of a young rabbit eye of 5-fluorouracil (5-FU) or thapsigargin in a sealed-capsule irrigation device.
Setting: St Erik's Eye Hospital, Stockholm, Sweden.
Methods: Clear lens extraction was performed unilaterally in eight 4-week-old rabbits. A sealed-capsule irrigation device was irrigated for 2 min with 20 ml of one of the following: balanced salt solution (BSS; n=2), thapsigargin 300 muM (n=2), 5-FU 50 mg/ml (n=2), or 5-FU 25 mg/ml (n=2). The substances were washed out for 10 s with BSS. The eyes were left aphakic. Six weeks postoperatively, the animals were killed, and the posterior capsule was extracted and fixed for TEM. As a control, we also evaluated the capsules from the two fellow eyes in the BSS group that did not undergo surgery.
Results: The ultrastructure of the posterior capsule in eyes irrigated with 5-FU or thapsigargin did not differ from that in the eyes irrigated with BSS or in the eyes that did not have surgery. The membranes had the same ultrastructure with thin collagen fibres on the anterior and posterior face of the posterior capsule and an amorphic matrix.
Conclusion: Thapsigargin or 5-FU used in a sealed-capsule irrigation device does not seem to harm the posterior capsule, which appeared similar to when the capsule is irrigated with BSS.