In vitro bovine ciliary body/epithelium in a small continuously perfused Ussing type chamber

Area of Science:

• Ophthalmology
• Epithelial Physiology
• Biomedical Engineering

Background:

• The bovine ciliary body/epithelium (CBE) plays a crucial role in ocular fluid dynamics and nutrient transport.
• Understanding its function requires a reliable in vitro model for physiological studies.

Purpose of the Study:

• To develop and validate a small-volume Ussing-type chamber for in vitro studies of the bovine ciliary body/epithelium (CBE).
• To assess the electrical stability, responsiveness to ouabain, and transport characteristics of the bovine CBE preparation.

Main Methods:

• Development of a novel small-volume Ussing-type chamber with continuous perfusion for bovine CBE.
• Monitoring of trans-CBE electrical parameters (potential difference, short circuit current, resistance).
• Measurement of [14C]-L-ascorbate and [3H]-L-glucose fluxes across the bovine CBE.

Main Results:

• The bovine CBE preparation exhibited stable electrical parameters: PD (-0.51 mV), SCC (-5.43 µA/cm²), and resistance (94 Ω·cm²).
• The preparation showed differential responses to ouabain on aqueous and stromal sides, indicating active transport mechanisms.
• Significant net ascorbate flux (0.26 nEq/h/cm²) from stroma to aqueous side and net chloride transport (0.81 µEq/h/cm²) were observed.
• L-glucose diffusion was comparable to other tight epithelia.

Conclusions:

• A viable in vitro bovine CBE model has been successfully developed.
• The model is electrically stable, responsive to ouabain, and capable of active ascorbate secretion.
• This model provides a valuable tool for investigating ocular physiology and transport mechanisms.