Establishment and evaluation of induced model of meibomian gland dysfunction in rats through eyeliner tattoo

AIM:To establish a model of meibomian gland dysfunction in rats induced by eyeliner tattoo and investigate its potential mechanisms.METHODS:A total of 40 SD rats were selected, with 30 randomly chosen to have eyeliner tattoo applied their right eyes and designated as the eyeliner group. The remaining 10 rats were not given any treatment and served as the normal group. The corneal morphology of both groups was observed using a slit lamp at 1, 2, and 4 wk after establishment, and the tear film break-up time(BUT), Schirmer I test(SIt), corneal fluorescein staining score, and corneal irregularity score were calculated. The corneal Placido rings were examined using an ocular surface analyzer, and the corneal tissue structures of both groups were observed under a confocal microscope. After 4 wk and completion of clinical indicator recording, the eyeballs and upper and lower eyelid tissues were taken for pathological examination. The meibomian gland structures were observed through HE staining, the conjunctival goblet cells were observed using PAS staining, and the lipid droplets were observed with ORO staining.RESULTS:The slit lamp examination results showed that the eyeliner group rats exhibited in situ black pigmentation in the eyelids, with no eyelid deformation or scarring. The corneal epithelium was rough, with positive fluorescein staining, presenting as spotty staining that worsened over time. Compared with the normal group, the BUT was significantly shortened, tear secretion volume was significantly decreased, and the corneal fluorescein staining score and corneal irregularity score were significantly increased at 1, 2, and 4 wk after modeling in the eyeliner group(all P