[Melatonin action in apoptosis and vascular endothelial growth factor in adrenal cortex of pinealectomized female rats].

PURPOSE: to evaluate the reactivity of VEGF-A and cleaved caspase-3 in the adrenal gland cortex of female pinealectomized rats treated with melatonin.

METHODS

forty adult female rats were divided into 4 groups (G) of 10 animals: GI - no surgical intervention, with vehicle administration; GII - sham pinealectomized with vehicle administration; GIII - pinealectomized with vehicle administration; GIV - pinealectomized with melatonin administration (10 µg/animal) during the night. After 60 days of treatment, all animals were anesthetized, and the adrenal glands were removed and fixed in 10% formaldehyde (phosphate buffered) for histological processing and paraffin embedding. Sections (5 µm thick) were collected on silanized slides and submitted to imunnohistochemical methods for the detection of cleaved caspase-3 (apoptosis) and of vascular endothelial growth factor (VEGF-A) in the adrenal cortex. The data obtained were submitted to analysis of variance (ANOVA) complemented by the Tukey-Kramer test (p≤0.05).

RESULTS

reactivity to cleaved Caspase-3 was noted in the zona glomerulosa of the adrenal glands in all studied groups. There were no significant differences in the zona glomerulosa; however, the zona fasciculata (15.51±3.12*, p≤0.05) and the zona reticularis (8.11±1.90*, p≤0.05) presented the smallest percentage of apoptosis in the pinealectomized group (GIII). The reactivity to the VEGF-A was stronger in the zona glomerulosa and weaker in the zona reticularis in all groups. We found a stronger VEGF-A reactivity in the zona fasciculata in the pinealectomized group (GIII).

CONCLUSIONS

the pineal gland affects the arrangement of the zona glomerulosa and reticularis of the adrenal glands, which are related to the production of sex hormones.