Abstract
Purpose :
The Harderian gland is a exocrine gland found within the orbit of many mammals except primates. The gland was first described in 1694 by Swiss anatomist Johann Jacob Harder. This gland excretes lipids to the ocular surface, but it produces not only lipids but also prophilins and melatonin. Coujard et al. reported in 1974 that, in aged rats, exorbital lacrimal gland partially became morphologically similar to the Harderian gland and named this phenomena “Harderianization”. However, it is still unknown if Harderianization also occurres in aged mice or not and if the Harderianized part of lacrimal gland functions as Harderian gland. To reveal these questions, we performed a histological study comparing between Harderian glands and Harderianized lacrimal glands in aged mice.
Methods :
C57BL/6 mice bred and maintained in the animal facility of our institute were used. Harderian glands and exorbital lacrimal glands from 0.5, 1 and 2 year-old mice were obtained and processed for histological analyses. Frozen sections of the glands were served for lipid staining using Sudan3, and paraffin sections were served for HE staining and immunohistochemical analyses. Primary antibodies used were anti-Mucin1 (MUC1) and anti-Smooth Muscle Actin (SMA) antibodies.
Results :
In almost all exorbital lacrimal glands from mice older than 1 year old showed morpholigical “Harderianization” and in the Harderianized area, lpid particles were detected by Sudan3 staining. Immunohistochemical study showed that MUC1 was positive on the apical side of the acinar cell membranes of Harderian glands and Harderianized parts of lacrimal gland while it was negative in normal lacrimal glands, and that SMA-positive myoepithelial calls were detected in normal lacrimal glands and Harderian glands, however it was negative in the Harderianized parts of lacrimal gland.
Conclusions :
“Harderianization” of lacrimal gland occures in in aged mice, but the Harderianized part of lacrimal gland is not identical to the Harderian gland.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.