The Role of Hormone Replacement Therapy on Structural Integrity of Lacrimal Gland in Ovariectomized Albino Rats (Histological and Immunohistochemical Study)

Background: Sex steroid hormones are important regulators of lacrimal gland functions. In addition, dry eye syndrome is common in menopausal women. Objective: This work was conducted to demonstrate the role of hormone replacement therapy (HRT) on structural integrity of the lacrimal gland of ovariectomized rats. Materials and Methods: Thirty six adult female albino rats, were used in the present work divided into three equal groups: Group I (control) and group II (bilaterally ovariectomized rats) sacrificed 1 and 12 weeks following ovariectomy. The third group contained ovariectomized rats receiving HRT was subdivided into: Subgroup IIIa received estradiol benzoate and subgroup III b received androgen. Small pieces of the gland were obtained and processed for different histological and immunohistochemical stains. Results: One week after ovariectomy the connective tissue septa was thickened. Collagen fibers were abundant with extensive cellular infiltration around dilated ducts and congested blood vessels. Some acinar cells were vacuolated and others contained darkly stained nuclei. Twelve weeks after ovarictomy, the acini were lined with low cuboidal cells and their lumina were widened with increased collagen fibers inbetween. In hormone treated group, the gland nearly regained its normal architecture, however few acinar cell nuclei showed hyperchromatism. In estrogen treated group some interlobular septa were widened. Concerning ERs immunoreactivity, in group ll, the acinar cell nuclei showed strong positive reaction in the first week then the reaction was negative after 12 weeks. The immune reaction for ERs remained negative after the HRT. One week after ovariectomy, the immune reaction for bcl-2 was weak in the cytoplasm of ductal cells and moderate in interstitial cells. After 12 weeks, they became immune negative and after estrogen and androgen treatment marked rise in their bcl-2 immune reactivity was observed. Conclusion: Sex hormone balance was proved to be a crucial factor in maintaining structural and functional integrity of lacrimal gland. So, future clinical therapeutic strategies based on estrogen and/or androgen replacement therapy for aged women and patients with premature ovarian failure could help in preventing or curing dry eye syndrome associated with lacrimal deficiency is adivsed.