Abstract
Purpose: :
At present little is known about secretion products of acessory lacrimal glands. In this study we compared mucin expression of these glands with main lacrimal glands.
Methods: :
Ten accessory lacrimal glands (ALG; glands of Krause) and ten main lacrimal glands (MLG) from cadavers were compared by immunohistochemistry using antibodies against mucins MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6, MUC7, MUC8, and MUC16.
Results: :
Results revealed expression of MUC1 and MUC8 in 10/10 ALG and 10/10 MLG. MUC2 and MUC6 were absent in both MLG and ALG (0/10 each). MUC3 occurred in 10/10 MLG and 6/10 ALG. MUC4 was only detected in 2/10 ALG. MUC5AC was present in 9/10 MLG and 9/10 ALG; MUC5B in 10/10 MLG and 8/10 ALG; MUC7 in 10/10 MLG and 9/10 ALG, and MUC16 in 8/10 MLG and 10/10 ALG. As MUC8 was present in all tissue specimens investigated and had never been described before at the ocular surface and in the lacrimal appartus we performed additionally RT-PCR, Western blot and immunohistochemistry for MUC8 in human cornea, conjunctiva, nasolacrimal ducts, MLG and ALG as well as a corneal and conjunctival epithelial cell line (HCE, HCjE). MUC8 transcripts were present in all structures investigated and were upregulated in HCE and HCjE after stimulation with bacterial supernatants. Moreover, MUC8 could be immunolocalized in all tissues investigated.
Conclusions: :
Our results show that ALG express the same mucin repertoire as MLG and that MUC8 is regularly present at the ocular surface and in the lacrimal apparatus.
Keywords: lacrimal gland • cornea: surface mucins • conjunctiva