Abstract: Topical tetracycline in rabbit dry eye model

This is from a veterinary journal but I thought I'd include it here for those that have been following the use of topical doxycycline in dry eye/MGD.

Efficacy of topically applied liposome-bound tetracycline in the treatment of dry eye model.

Objective
To evaluate the effects of liposome-bound tetracycline eye drops in a rabbit dry eye model evaluating their advantage of being less allergic, preservative free and prolonged action compared with other tear substitutes.

Procedures
New Zealand albino rabbits were equally divided into control group and dry eye induced groups. Dryness was induced in 24 eyes of 12 healthy adult male albino rabbits by instilling atropine sulfate eye drops 1% three times daily for 1 week, then animals were subdivided into four groups; group 1 (rabbits with dry eye model), groups 2, 3, and 4: rabbits with dry eye model treated for 7 days starting on 7th day of dryness induction with either tetracycline, empty liposome, or combined tetracycline with liposome as topical eye drops respectively. Schirmer (STT) test and tear break up time (TBUT) were assessed on days 0, 2, 4, 7, 9, 11, and 14. Animals were sacrificed on day 14 and histopathological examination of the cornea and conjunctiva was performed.

Results
Tear break up time and STT test values were significantly improved in groups 2, 3, 4 as compared with group 1. The histopathological examination showed normal cytoarchitecture of corneas and conjunctivae in groups 2, 3, 4 against the dryness effect that continued to affect the cornea and conjunctival epithelium in group 1. There was a significant improvement in the group treated with liposome-bound tetracycline eye drops (group 4) as compared with tetracycline alone (group 2) and empty liposome (group 3).

Conclusion
The use of liposome encapsulated tetracycline significantly improved STT and TBUT values as well as reverse surface ocular pathology.

Vet Ophthalmol. 2011 Jan;14(1):18-25. doi: 10.1111/j.1463-5224.2010.00834.x.
Shafaa MW, El Shazly LH, El Shazly AH, El Gohary AA, El Hossary GG.
Department of Physics, Faculty of Science, Helwan University, Cairo, Egypt Department of Ophthalmology and Pathology, Memorial Institute of Ophthalmology, Giza, Egypt Departments of Physiology and Pharmacology, Research Institute of Ophthalmology, Giza, Egypt.