Sab. Sibayan et al., APOPTOSIS AND MORPHOLOGIC CHANGES IN DRUG-TREATED TRABECULAR MESHWORKCELLS IN-VITRO, Experimental Eye Research, 66(5), 1998, pp. 521-529
Using an in vitro culture system, we investigated whether bovine trabe
cuIar meshwork cells undergo apoptosis (programmed cell death) followi
ng exposure to anti-glaucoma medications (timolol, pilocarpine and epi
nephrine) and known inducers of apoptosis (5-fluorouracil, mitomycin-C
and dexamethasone). Third to fifth passage bovine trabecular meshwork
cells were grown to confluence and incubated for 1-12 days in growth
media with timolol (1-1000 mu M), pilocarpine (15-15000 mu M), epineph
rine (5-5000 mu M), 5-fluorouracil (10-100 mu g ml(-1)), mitomycin-C (
0.01-100 mu g ml(-1)) and dexamethasone (0.01-100 mu M). The cultures
were evaluated for apoptosis by phase-contrast microscopy, transmissio
n electron microscopy and in situ apoptosis labeling. 5-Fluorouracil (
10-100 mu g ml(-1)), mitomycin-C (0.1-100 mu g ml-l) and epinephrine (
500-5000 mu M) induced apoptosis in a dose and time-dependent manner.
Timolol, pilocarpine, and dexamethasone-treated specimens did not show
evidence of apoptosis at any of the concentrations tested. Trabecular
meshwork cells incubated in timolol (100-1000 mu M) developed cytopla
smic granules, and specimens treated with pilocarpine (15000 mu M) dev
eloped cytoplasmic vacuoles. These granules and vacuoles have the appe
arance of secondary lysosomes. Dexamethasone-treated cells developed a
n increased number of mitochondria. This study suggests that the trabe
cular meshwork may undergo apoptosis following exposure to 5-fluoroura
cil, mitomycin-C and epinephrine. Timolol, pilocarpine and dexamethaso
ne did not induce apoptosis. However, these drugs can incite character
istic morphologic changes in cultured trabecular meshwork cells. (C) 1
998 Academic Press Limited.