The sclera is a part of the human eye ("white of the eye"), mainly composed of collagen fibrils. Several factors can influence the correct formation and structure of these collagen fibrils. Therefore, the expression of several genes related to the collagen synthesis was examined.
The retina is the source of ocular growth-regulating signals and retinal pigment epithelial cells are intimately involved in eye growth regulation. For this reason, supernatant from separately pre-exposed retinal pigment epithelial cells was added to the scleral fibroblasts during the exposure.
Exposure duration: continuous for 24 hours
|Setup||magnetic fields were generated in a device constructed by winding 150 turns of insulated soft copper wire with a diameter of 1.5 mm; three horizontally parallel Helmholtz coils (16 cm length, 14 cm width, 8 cm height) and one slidac; coils were placed vertically, facing one another; exposure system was put in a humidified incubator at 37 °C, which contained 5% CO2; cells were placed between the coils|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||0.2 mT||-||measured||-||-|
Magnetic field-exposed cell cultures of scleral fibroblasts showed a significant reduced proliferation rate compared to not-exposed ones. An addition of the supernatant of retinal pigment epithelial cells led again to a significant decrease in the proliferation rate compared to those exposed to the magnetic field only.
In exposed scleral fibroblasts, the expression of collagen I was significantly decreased compared to the control cell cultures, while the expression of matrix-metalloproteinase-2 was significantly increased. This effect could be significantly enhanced through the addition of retinal pigment epithelial cell supernatant. In comparison to the control cell culture of scleral fibroblasts, the levels of ERK1/2 and p38 MAP kinase were significantly increased in the exposed cell cultures, while an addition of retinal pigment epithelial cell supernatant led again to a significant increase compared to those exposed to magnetic fields alone.
The authors conclude that exposure to extremely low frequency magnetic fields can influence the collagen synthesis in human scleral fibroblasts and hence could disturb the formation of the sclera.