The effect of estrogen and androgen on lacrimal secretion and expression of apoptosis genes in lachrymal gland in ovariectomized rat / 眼科研究

ABSTRACT

Objective Some scholars considered that dry eye is associated to serum sex level in elder female population.But,how the estrogen and/or androgen play role in dry eye is still in controversy.The goal of the present study was to investigate the effect of estrogen and androgen on lacrimal secretion and expression of apoptosis genes in the lachrymal gland in ovariectomized rat.MethodsSixty-four female Wistar rats were divided into normal contol group,sham operation group and experiment group randomly.Ovariectomy (OVX) was performed in the rats of the experiment group and only partial fat tissue in abdominal cavity was cut in the sham operation group.Lacrimal secretion (Schirmer Ⅰ test),tear film breakup time (BUT) and corneal fluorescence staining examinations were measured in all rats before and 1,2,3,4 and 5 months after the operation.Corn oil,estrogen and androgen were systemically and topically applied 5 months after the operation for six weeks in the OVX experiment group.The experimental rats were sacrificed and the lachrymal glands were obtained for pathohistological examination.The serum estrogen and androgen levels were detected before and 5 months after the operation and before death.The expressions of bax and bcl-2 were detected by immunohistochemistry in the different groups.ResultsThe serum estrogen and androgen levels were significantly decreased after OVX in comaprison with before OVX (P＜0.05).The BUT was obviously shorter in the 1 month after OVX group (P＜0.05).The result of the Schirmer Ⅰ test decreased to 50% in 3 months after OVX (P＜0.01).Corneal fluorescence staining showed positive staining 4 months after OVX and stronger staining 5 months after OVX.In the sixth week after use of androgen,the results of BUT and Schirmer Ⅰ test were considerably decreased but stronger corneal fluorescence straining was seen.However,a complete contrary outcome was found in systemic androgen treatment rats.The expression of bax in lacrimal epithelium cells was increased after estrogen treatment and declinded after androgen treatment.The expression of bcl-2 in lacrimal epithelium cells was declinded after estrogen treatment and increased after androgen treatment.ConclusionIt is supposed that decrease of lacrimal secretion in OVX rats is associated with the decrease of serum androgen.The treatment with androgen can improve lacrimal secretion and decrease the expression of apoptosis gene in lachrymal gland in ovariectomized rat.The apoptosis of lachrymal gland epithelium is one of mechanisms of dry eye.