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Efrain Romo-Garcia, Axel Orozco-Hernández, Javier Flores-Estrada, Jans Fromow-Guerra, Everardo Hernandez-Quintela, Juan Manuel Jimenez-Sierra, Virgilio Morales-Canton; Toxicity Study of 3-Epigallocatequin Gallate (EGCG) In An Animal Model. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5632.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the safety of intravitreal injection of EGCG in rabbit eyes.
We performed intravitreal injections of EGCG at different concentrations to the right eye of New Zeland rabbits. We studied 3 groups of 5 eyes each: Group 1 received an intravitreal injection of 50ug/0.1cc, group 2 100ug/0.1cc and group 3 500ug/0.1cc. Standard electroretinograms were done at baseline, 1 week and 1 month after the injections. Eyes were enucleated at 1 month and studied histopatologically for structural damage of the retina.
The photopic a-wave amplitude in group 1 was reduced in 20% at 1 week (4mv, range 3-5mv) and 1 month (4mv, range 3-6mv) compare with baseline (5mv, range 3-7mv); in group 2, a 40% reduction was found at 1 week (3mv, range 3-6mv) and 1 month (3mv, range 1-4mv); and in group 3 at 1 week the reduction was in 60% (2mv, range 2-4mv) and no electrical response at 1 month. The amplitude in photopic b-wave have no changes for groups 1 and 2 comparing with baseline results, contrary to group 3 were at 1 week there was a reduction of 9.58% (66mv, range 65-68mv) and in 56.16% (32mv, range 30-33mv) compare to initial response (73mv, range 71-74mv). The implicit time of photopic a-wave for group 1 have no changes; group 2 presented a prolonged response at 1 week (18.7% increment) and 1 month (37.5% increment) when comparing with baseline response; in group 3 there was also a prolonged response, at 1 week of 31.25% (21ms, range 20-23ms), and 62.5% at 1 month (42ms, range 40-45ms). Prolonged b-wave implicit time was presented at 1 week (30ms, range 28-30ms) and continued with same response at 1 month. In group 2 we also found prolonged response at 1 week (17.24%) and at 1 month (20.68%), as well as in group 3, were at 1 week showed a 44.82% and at 1 month a 90% prolonged response compare to baseline. There were no structural damage when performing histological exam for any of the 3 groups.
Our results suggests that 3-epigallocatequin gallate in high concentrations could have a direct effect in the electric response of the retina evoking functional damage. Careful and more studies about safety have to be done before using ECGC in humans' vitreous cavity. Evaluation on lower concentrations of ECGC and their therapeutic effect must be performed.
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