effects of decaffeinated and non-decaffeinated green coffee and green tea extract on lens opacity, αb-crystallin expression and aggregation in rat model of metabolic syndrome

Metabolic syndrome (mets) causes significant damage to the eyes, which can lead to conditions such as cataracts. previously, both green tea extract (gt) and green coffee (gc) extract could improve the metabolic profile and systemic inflammatory conditions such as diabetes mellitus and hypertension in a rat models with mets. we investigated the potential effects of a combination of green coffee and green tea extracts on the lens opacity, expression, and aggregation of αb-crystallin lens in a rat model of mets. we conducted an experimental study on twenty-four sprague dawley rats, dividing them into four groups: a positive control (mets only), a negative control, a combination of decaffeinated (decaf) extracts, and a combination of non-decaffeinated (non-decaf) extracts. we administered high fat, high sucrose, and streptozocin to all samples, except those in the control group, to induce mets for 8 weeks. after developing mets, the treatment groups were administered an of 0.3 gram/kgbb + gc of 0.2 gram/kgbb decaffeinated (n = 6) and an gt of 0.3 gram/kgbb + gc 0.2 gram/kgbb non-decaf (n = 6) for 9 weeks. after completing the intervention, we enucleated the lens, evaluated the degree of lens opacity using a slitlamp (topcon, tokyo, japan), and assessed the expression and aggregation using western blot analysis. the decaf combination promotes native lens αb-crystallin more effectively than the non-decaf combination (p = 0.000). however, neither the decaf nor the non-decaf combination had a significant effect on lens opacity (kruskal-wallis test, p = 0.202) or αb-crystallin aggregation (p = 0.054).