Recent studies have reported an association between
myopia development and local ocular
inflammation.
Lactoferrin (LF) is an
iron-binding protein present in saliva, tears, and mother's milk. Furthermore, sequestering
iron by LF can cause its antibacterial property. Moreover, LF has an anti-inflammatory effect. We aimed to determine the suppressive effect of LF against the development and progress of
myopia using a murine lens-induced
myopia (LIM) model. We divided male C57BL/6J mice (3 weeks old) into two groups. While the experimental group was orally administered LF (1600 mg/kg/day, from 3-weeks-old to 7-weeks-old), a similar volume of
Ringer's solution was administered to the control group. We subjected the 4-week-old mice to -30 diopter
lenses and no
lenses on the right and left eyes, respectively. We measured the refraction and the axial length at baseline and 3 weeks after using a refractometer and a spectral domain optical coherence tomography (SD-OCT) system in both eyes. Furthermore, we determined the
matrix metalloproteinase-2 (MMP-2) activity, and the amount of
interleukin-6 (IL-6), MMP-2, and
collagen 1A1 in the choroid or sclera. The eyes with a minus lens showed a
refractive error shift and an axial length elongation in the control group, thus indicating the successful induction of
myopia. However, there were no significant differences in the aforementioned parameters in the LF group. While LIM increased
IL-6 expression and MMP-2 activity, it decreased
collagen 1A1 content. However, orally administered LF reversed these effects. Thus,
oral administration of LF suppressed lens-induced
myopia development by modifying the extracellular matrix remodeling through the IL-6-MMP-2 axis in mice.