ALTERATIONS OF THE ESTROGEN RECEPTOR EXPRESSION IN RETINA OF LITHIUM-TREATED VISCACHAS (Lagostomus maximus maximus)

MONCHO QUIROGA MARÍA VICTORIA; ROSALES GABRIELA; PÉREZ EDITH; FILIPPA VERÓNICA; MOHAMED FABIAN

Virtual

Congreso; XXXIX Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2021

Sociedad de Biología de Cuyo

The estrogen receptors α (ERα) has been reported in the retinal layers and they were involved in neuroprotective functions through their ability to regulate apoptosis, phagocytosis and antioxidant processes. Previous studies in viscacha retina have demonstrated a daily rhythm of photoreceptor renewal. Lithium (Li) modifies this process probably by inhibiting of phagocytosis in pigment epithelial cells. The aim of this work was to study the effects of lithium administration on the expression of ERα in retina. Adult male viscachas were divided into 2 groups, the control group and the experimental group that received lithium chloride (1 mmol/kg body weight/day) for 35 days. Retinas were obtained at 08:00, 16:00, and 24:00 h (n = 4 for each group). They were processed for light microscopy. The primary antibody anti-ERα (MC20):sc-542 was used by the immunohistochemistry. The percentage of immunoreactive (-ir) cells was quantified by morphometric analysis. The data were analyzed statistically. Nuclear immunostaining in cells of the inner nuclear layer (INL) and in ganglion cells (GC) was observed in the retina from control and experimental groups. In the INL of the control group, the %ERα-ir cells was maximal at 8:00 (24.51 ± 2.31). No immunostaining was detected at 16:00 h and the % ERα-ir presented a minimal value (6.61 ± 0.38) at 24:00 h (p < 0.01). The %ERα-ir cells of the experimental group was maximal at 8:00 h (42.46 ± 1.33), decreased at 16:00 h (24.39 ± 0.32), and it was minimal (4.03 ± 1.47) at 24:00 h (p < 0.01). Thus, in the INL the %ERα-ir cells were significantly higher in the experimental group than in the control group at 8:00 h and at 16:00 h (p < 0.001). In the layer of GC, the %ERα-ir cells in the control group was maximal at 8:00 h (41.82 ± 4.13). No immunostaining was detected at 16:00 h, and the % ERα-ir GC presented a minimal value (11.96 ± 1.01) at 24:00 h (p < 0.01). The %ERα-ir GC in the experimental group were similar at 8:00 h (43.61 ± 6.91) and at 16:00 h (54.15 ± 1.50), but it was not detectable at 24:00 h. Thus, the %ERα-ir GC did not show significant differences between experimental and control groups at 8:00 h (p > 0.05). However, the expression of ERα in GC was different at 16:00 h and 24:00 h between two groups. These results show that the expression of ERα presents a circadian rhythm directly related to the thickness of the photoreceptor layer previously studied. The Li-treatment alters the expression of ERα in the layers of the retina and this might change the daily renewal process of photoreceptors.