Radioprotective effect of montelukast sodium in rat lacrimal glands after radioiodine treatment.

PURPOSE: The aim of this study was to evaluate the morphological changes of rat lacrimal glands at the third month following radioiodine (RAI) treatment and the radioprotective effect of montelukast (ML) sodium against RAI-related lacrimal gland damage. METHODS: Fifty female Wistar Albino rats were divided into three groups. The control group (n=10) consisted of rats with no intervention. RAI group (n=20) consisted of rats treated with oral (131)I (111 MBq). The ML group (n=20) consisted of rats treated with intraperitoneal 10mg/kg/day ML sodium, starting three days before and continuing for one week after oral RAI administration. Intraorbital (IG), extraorbital (EG) and Harderian glands (HG) were removed bilaterally after three months. RESULTS: The existence of acinar atrophy, acinar fibrosis, abnormal cell lines, peripheral basophilia, cell size variation and decrease in amount of cytoplasm was significantly more common in the RAI-rat treated group than in the ML group, in each of the glands. The ML-treated group had less-frequent cell shape variation in EG (P=0.001) and HG (P=0.027), cell size variation in IG (P<0.001) and HG (P=0.01), ductal pathology in EG (P<0.001) and HG (P<0.001) and lipofuscin accumulation in EG (P=0.001) and in HG (P=0.01) than the RAI-treated group. CONCLUSIONS: RAI treatment seems to cause morphological damage to rat lacrimal glands, and ML sodium effectively protects against damage to lacrimal glands.

Dietary lactoferrin alleviates age-related lacrimal gland dysfunction in mice.

BACKGROUND: Decrease in lacrimal gland secretory function is related to age-induced dry eye disease. Lactoferrin, the main glycoprotein component of tears, has multiple functions, including anti-inflammatory effects and the promotion of cell growth. We investigated how oral administration of lactoferrin affects age-related lacrimal dysfunction. METHODS AND FINDINGS: Twelve-month-old male C57BL/6Cr Slc mice were randomly divided into a control fed group and an oral lactoferrin treatment group. Tear function was measured at a 6-month time-point. After euthanasia, the lacrimal glands were subjected to histological examination with 8-hydroxy-2'-deoxyguanosine (8-OHdG) antibodies, and serum concentrations of 8-OHdG and hexanoyl-lysine adduct (HEL) were evaluated. Additionally, monocyte chemotactic protein-1(MCP-1) and tumor necrosis factor-α (TNF-α) gene expression levels were determined by real-time PCR. The volume of tear secretion was significantly larger in the treated group than in the control. Lactoferrin administration reduced inflammatory cell infiltration and the MCP-1 and TNF-α expression levels. Serum concentrations of 8-OHdG and HEL in the lactoferrin group were lower than those in the control group and were associated with attenuated 8-OHdG immunostaining of the lacrimal glands. CONCLUSION: Oral lactoferrin administration preserves lacrimal gland function in aged mice by attenuating oxidative damage and suppressing subsequent gland inflammation.

Rabbit lacrimal acinar cells in primary culture: morphology and acute responses to cholinergic stimulation.

PURPOSE: The rabbit lacrimal gland yields large numbers of viable acinar cells that, when exposed to carbachol, respond with accelerated protein release, fluid phase endocytosis (Lucifer yellow uptake), and Na/H antiport activation. The current study was undertaken to determine whether such cells exhibit similar responses after having been maintained in primary culture. METHODS: Cells were isolated from 2-kg, juvenile male New Zealand White rabbits and maintained in a supplemented DMEM/Ham's F-12 medium for up to 72 hours. RESULTS: Electron microscopy showed the organization of freshly isolated cells to be highly polarized, with secretory vesicles at one pole and nucleus at the other; vesicles were heterogeneous in size and in the electron density of their contents. The cells remained polarized after overnight culture, but the secretory vesicle population was more homogeneous in size and content, and the cells tended to aggregate. After 72 hours, roughly half the cells retained good morphology and cytoplasmic polarization, but the vesicles were enlarged and their contents less electron dense. Cells that had been maintained overnight responded to the addition of 10 microM carbachol with a 32.2% +/- 15.5% (n = 12, P < 0.04) increase in the total amount protein released during a standard 20-minute incubation. This represented a mean 125% increase in the temperature-dependent component of protein release. The protein secretory response was decreased to 14.6% +/- 6.1% (n = 3, P < 0.07) for cells that had been maintained for 72 hours. In the same samples, carbachol increased fluid phase endocytosis by 38.3% +/- 8.1% (P < 0.01) and 70.9% +/- 13.4% (P < 0.025), respectively. The protein secretory response was partially, and the endocytic response fully blocked by 1 mM atropine. CONCLUSIONS: This model could be useful as a simplified system in which to study regulation of acinar cell function over days, rather than hours, as is required in fresh tissue models.

Pathologic changes in the exorbital lacrimal gland of the vitamin A-deficient rat.

Histologic changes in lacrimal glands of vitamin A-deficient (A-) and pair-fed control rats were compared. In A- lacrimal glands, secretory granules were strikingly diminished, and rough endoplasmic reticulum appeared somewhat atrophic. Nuclei of acinar cells were hyperchromatic and pleomorphic. Using alcian blue-PAS, no positive staining was present in acini of A- lacrimal glands, whereas in controls apical portions of acini were intensely stained. Thus, lacrimal tissues of A- rats were thought to be poorly differentiated as a glandular epithelium. When A- rats were supplemented with retinyl acetate, secretory granules reappeared, rough endoplasmic reticulum cisternae greatly dilated, and mitochondria proliferated, indicating accelerated secretory activity. Resupply of vitamin A can induce glandular differentiation in A- lacrimal tissues. Tear volume was not decreased in A- rats compared with pair-fed controls. Regression of secretory organelles in A- lacrimal tissues may lead to a decrease in protein and mucoprotein secretion and subsequent changes in tear composition.

Growth of exocrine acinar cells on a reconstituted basement membrane gel.

Methods have been developed for culturing a dividing population of morphologically differentiated rat parotid, lacrimal, and pancreatic acinar cells in vitro. Isolated acinar cells were plated onto tissue culture dishes coated with a three-dimensional, reconstituted basement membrane gel. After attachment in Ham's nutrient mixture F12, the cells were cultured at 35 degrees C in F12 supplemented with 10% heat inactivated rat serum, epidermal growth factor, dexamethasone, insulin, transferrin, selenium, putrescine, reduced glutathione, ascorbate, penicillin, streptomycin, and the appropriate secretagogue. Under these conditions, the cells attached rapidly and DNA synthesis was initiated within 2 to 3 d. Although the cells flattened on the substratum, they continued to maintain their differentiated morphology. The cells contained secretory granules, and the secretory enzymes peroxidase and amylase could be detected. The use of a reconstituted basement membrane gel proved critical for the attachment and growth of exocrine acinar cells.

Argyrosis of the lacrimal sac.

Silver deposition in the wall of the lacrimal sac after prolonged application of mild silver protein (Argyrol) eye drops is documented at the light and electron microscopical level. Silver granules were found in the extracellular matrix predominantly on elastic fibres and within cells forming conglomerates in secondary lysosomes. Most of the silver-containing cells showed a prominent rough endoplasmic reticulum, suggesting their fibroblastic origin. Investigation by energy-dispersive analysis of X-rays (EDAX) indicated the precipitation of silver as selenide.