Abstract
Abstract: :
Purpose: To quantify the diffusion coefficient (Kd) of the blood aqueous barrier (BAB) in rhesus monkeys and determine the amount of toxin required to compromise barrier integrity. Methods: Adult female rhesus monkey (macaca mulatta) were first subjected to slit lamp examination for flare, then scanned fluorophotometrically 2 hr. following topical bilateral application of saline or intravenous injection of lipopolysaccharide (LPS). Six monkeys received saline in the first week and two weeks later, monkeys from the same group were treated intravenously with various doses of LPS (0.5, 10 and 20 ug / kg). Sodium fluorescein (8 mg/Kg) was used as the tracer dye and applied intravenously. The Fluorotron Master (OcuMetrics) anterior chamber adaptor was mounted for fluorophotometric measurements. Baseline fluorescence of each eye was recorded, followed by dye application and subsequent fluorophotometry at 30, 45 and 60 min. Blood was collected from each animal at 5, 35 and 55 min post fluorescein application. After ultrafiltration with microcon tubes, unbound plasma fluorescin concentration was determined fluorophotometrically. BAB diffusion coefficient was calculated using the EuroEye–Software, BRB of Dr. van Best. Results:In saline–treated rhesus monkeys, the calculated Kd = 101.8 ±5.1 X 10–6. LPS produced dose–dependent increases in barrier permeability to sodium fluorescein. LPS (0.5, 10 and 20 ug/kg) calculated Kds = 105 ±2.4 X 10–6, 168.8 ±12.8 X 10–6 and 262.8 ±12.8 X 10–6 , respectively. Conclusions: This study showed that the BAB diffusion coefficient in normal rhesus monkeys is approximately 101.8 ±5.1 X 10–6. In addition, an intravenous LPS dose of 10 ug/kg is sufficient to induce flare in this species as potential animal model of uveitis.
Keywords: uveitis-clinical/animal model • aqueous