Abstract
Purpose: :
Bruch’s membrane mediates the bi-directional transport of nutrients and waste products, a process essential for photoreceptor maintenance. In age-related macular degeneration (AMD), the gross structural damage and accumulation of ‘debris’ severely curtails the transportation capability of Bruch’s membrane. Given the anti-oxidative, metal chelating and saponin-like properties of ginseng compounds, their possible use for improving the transportation characteristics of Bruch’s has been assessed.
Methods: :
Bruch’s-choroid preparations (from 11 donors aged 31-87 years) were mounted in open-type Ussing chambers and hydraulic conductivity calculated from the amount of fluid transported under a hydrostatic pressure of 3088Pa. Seven of the preparations were incubated with 10% ginseng (in Tris-HCl buffer, pH 7.5) for 20 hours at 37oC whilst the remainder were incubated in Tris-HCl alone. Measurements of hydraulic conductivity were repeated.
Results: :
In the young donor subset (n=3, ages 30-35 years), the basal hydraulic conductivity was determined as 5.35 ± 1.83 x10-10 m/sec/Pa (Mean ± SD). In the elderly donors (n=8, ages 75-87 years), basal hydraulic conductivity was determined as 0.72 ± 0.14 x 10-10 m/sec/Pa (Mean ± SD). Basal conductivities of individual donors were designated as 1.0 and changes in response to incubation for 20 hours were calculated as fold change of basal values. Incubation with Tris-HCl alone increased conductivities to 1.32 ±0.16 -fold of basal, p<0.05. Incubation with 10% ginseng increased conductivities 2.6 ± 0.7-fold, p<0.001.
Conclusions: :
The 2.7-fold increase in hydraulic conductivity following a 20-hour incubation in 10% ginseng is equivalent to the hydraulic conductivities of donors 23 years younger. Ginseng mediated improvement in the transport properties of Bruch’s may therefore slow the progressive degeneration in AMD and serve as a preventive measure in early AMD.
Keywords: Bruch's membrane • aging • age-related macular degeneration