Abstract
Purpose :
To investigate the structural changes in the meibomian gland after applying external pressure using magnets and cryotheraphy using frozen carbon dioxide in rats.
Methods :
In the experiment 1, the upper eyelid was externally compressed using pair of neodymium magnets (35 psi) in rat for 1 hour a day for 5 days (the external pressure group). In the experiment 2, the middle portion of upper eyelid palpebral conjunctiva was contacted with frozen carbon dioxide for 3 seconds and this was repeated 6 times (the freezing group). The untreated eyes were used as controls (the control group). The eyelid sections were stained with H&E and anti-cytokeratin 5 antibody. Meibography was performed.
Results :
One day after external pressure for 5 days, the mean area of secretory acini was decreased in the external pressure group (0.039 ± 0.023 um2) compared to the control (0.081 ± 0.020 um2). However, after 2 weeks of recovery, there was no difference in the area of secretory acini between the two groups. Similarly, meibography showed meibomian gland loss 1 day after external pressure (32.2 ± 11.1%), but not after 2 weeks of recovery (5.3 ± 0.5%). One week after cryotherapy, the meibocyte cell walls were destroyed and the nuclei were crowded around the duct. 4 weeks after cryotherapy, many secretory acini still have abnormal morphology. One and 4 weeks after cryotherapy, meibography showed increased meibomian gland loss in the freezing group (21.3 ± 11.5% and 16.9 ± 5.2%, respectively) compared to the control group (5.5 ± 0.3%).
Conclusions :
Repeated application of external pressure on the eyelid could induce meibomian gland loss, however this meibomian gland loss can be restored when the external pressure is removed. Thus, the repeated application of external pressure on the eyelid is a safe treatment method for obstructive meibomian gland dysfunction (MGD). On the other hand, the application of cryotherapy induced the destruction of meibocytes. Thus, the application of cryolipolysis on the meibomian gland may be used to evaluate the pathogenesis of a meibocyte-centric MGD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.