Glycosaminoglycan Distribution in the Rat Uterine Cervix During the Estrous Cycle

Abstract

OBJECTIVE:To analyze the amount of glycosaminoglycans in the uterine cervix during each phase of the rat estrous cycle.DESIGN:Based on vaginal smears, forty female, regularly cycling rats were divided into four groups (n = 10 for each group): GI – proestrous, GII – estrous, GIII – metaestrous and GIV – diestrous. Animals were sacrificed at each phase of the cycle, and the cervix was immediately removed and submitted to biochemical extraction and determination of sulfated glycosaminoglycans and hyaluronic acid. The results were analyzed by ANOVA followed by the Bonferroni post-hoc test.RESULTS:The uterine cervix had the highest amount of total sulfated glycosaminoglycans and dermatan sulfate during the estrous phase (8.90 ± 0.55 mg/g of cetonic extract, p<0.001; and 8.86 ± 0.57 mg/g of cetonic extract, p<0.001). In addition, there was more heparan sulfate at the cervix during the proestrous phase (0.185 ± 0.03 mg/g of cetonic extract) than during any other phase (p<0.001). There were no significant changes in the concentration of hyaluronic acid in the uterine cervix during the estrous cycle.CONCLUSION:Our data suggest that the amount of total sulfated glycosaminoglycans may be influenced by hormonal fluctuations related to the estrous cycle, with dermatan sulfate and heparan sulfate being the glycosaminoglycans most sensitive to hormonal change.

Ovarian status modulates cardiovascular autonomic control and oxidative stress in target organs

“…In rats, the duration of the estrous cycle is short and the changes in the levels of estrogen and progesterone secreted by the ovarian are very intense during the different stages of the cycle. Ovulation usually occurs at the end of the estrus phase, when estrogen levels are lower [26,27], as observed in the present study. Our findings showed that oscillation of ovarian hormones during the estrous cycle results in transitory changes in AP, as demonstrated by the increased AP in females in the ovulatory phases when compared to females in the non-ovulatory phases of the estrous cycle.…”

“…The differences in AP between two phases (ovulatory and non-ovulatory) of the estrous cycle assessment in our study may be explained by the possible counterbalancing effect of estrogen on the cardiovascular system. Indeed, studies have found that progesterone concentrations were low in the estrus (ovulatory) and diestrus (non-ovulatory) phases of the estrous cycle in rats [26,27]. Therefore, the increased AP in the FOV group is probably related to transitory reduced protective cardiovascular effects of estrogen.…”

Composition and significance of glycosaminoglycans in the uterus and placenta of mammals

“…An increase in sulfated GAGs in the uterus, especially the increase of CS and DS, occurs in female rats´ estrogen phase, whereas in the progesterone phase there is a slight HS increase. The high concentration of GAGs during estrum foregrounds the uterus´s macroscopic increase, since these molecules trigger tissue hydration and, at the same time, tissue hyperplasia (Cubas et al 2010). Studies on bitches during the anestrus phases or estrus and the comparison of GAGs rates in the fluids of the ampulla and isthmus of the uterine tubes and the lumen of the uterine horns showed that GAGs concentrations in these organs are greater in the bitches in the estrus when compared to those in the anestrus phase (Kawakami et al 2000).…”