Ascorbate in the guinea pig lens: dependence on drinking water supplementation

Area of Science:

• Ophthalmology
• Nutritional Science
• Biochemistry

Background:

• Lens ascorbate (vitamin C) is crucial for ocular health.
• Maintaining adequate ascorbate levels in the lens may prevent oxidative damage.
• Dietary intake is a primary source of ascorbate, but its direct impact on lens concentration via supplementation needs investigation.

Purpose of the Study:

• To determine if oral L-ascorbate supplementation can increase the concentration of ascorbate within the eye lens.
• To evaluate the efficacy of drinking water as a delivery method for ascorbate supplementation.
• To assess if elevated lens ascorbate levels occur without adverse effects like cataract formation.

Main Methods:

• Pigmented guinea pigs were administered drinking water with varying L-ascorbate concentrations (0.00-8.52 mM) for 4 weeks, alongside standard chow containing ascorbate.
• Whole lenses were extracted post-supplementation and processed for ascorbate measurement.
• High-performance liquid chromatography (HPLC) with UV detection was employed to quantify lens ascorbate concentrations.
• Regression analysis was used to model the relationship between water supplementation and lens ascorbate levels.

Main Results:

• All guinea pig lenses remained cataract-free throughout the study.
• Detectable concentrations of ascorbate were found in all lenses.
• Lens ascorbate concentration showed a positive correlation with the concentration of L-ascorbate in the drinking water.
• A mathematical model ([Asc(lens)] = A - Be(-kAsc(water)]) described this relationship.

Conclusions:

• Drinking water supplementation with L-ascorbate effectively increases lens ascorbate concentration in guinea pigs.
• This supplementation strategy appears safe, as no cataract development was observed.
• The HPLC method utilized is validated as suitable for measuring whole lens ascorbate content.