Genetic relationships between early menopause and the behaviour of theca interna during follicular atresia

ABSTRACT Genetic variants are known to contribute to about 50% of the heritability of the age of menopause and recent studies suggest that genes associated with genome maintenance are involved. The idea that increased rates of follicular atresia could lead to depletion of the primoridial follicle reserve and early menopause has also been canvassed, but there is no direct evidence of this. In studies of the transcriptomics of follicular atresia, it was found that in the theca interna, the largest group of genes are in fact down-regulated and associated with ‘cell cycle and DNA replication’, in contrast with the up-regulation of apoptosis-associated genes which occurs in granulosa cells. Many of the genes down-regulated in the theca interna are the same as or related to the genes in loci associated with early menopause. From these findings, we suggest that early menopause could be due to increased rates of follicular atresia initiated from the theca interna.

Melatonin effects on ovarian follicular cells: a systematic review

SUMMARY Melatonin is known for its effects on both the sleep and reproductive system of mammals. The latter has melatonin receptors type 1 and 2, which act to regulate, among other things, cyclic AMP. Notwithstanding all the literature data, there is still no sound knowledge or a clear understanding of the hormone’s action on the physiology of ovarian follicular cells. OBJECTIVE To review and evaluate studies about melatonin action on the ovarian granulosa/theca interna cells from the literature. METHODS The systematic review was carried out according to the PRISMA recommendations. The MEDLINE and Cochrane primary databases were consulted with the use of specific terms. There was no limitation on language or publication year. RESULTS Seven papers about melatonin action on granulosa cells were selected. The following can be attributed to the hormone’s effects: a) progesterone increase in culture medium; b) increased estrogen production; c) antagonistic action on estrogen; d) improvement in cell quality resulting in improved embryo and higher pregnancy rates; e) improved cell proliferation via MAPK; f) reduction of free radicals. Nevertheless, there are contrarian papers reporting a reduction in progesterone production. CONCLUSION Melatonin interferes in sex steroid production, boosting progesterone output. Such action may help improve oocyte quality.

Transcriptome analyses of ovarian stroma: tunica albuginea, interstitium and theca interna

The ovary has specialised stromal compartments, including the tunica albuginea, interstitial stroma and theca interna, which develops concurrently with the follicular antrum. To characterise the molecular determinants of these compartments, stroma adjacent to preantral follicles (pre-theca), interstitium and tunica albuginea were laser microdissected (n = 4 per group) and theca interna was dissected from bovine antral follicles (n = 6). RNA microarray analysis showed minimal differences between interstitial stroma and pre-theca, and these were combined for some analyses and referred to as stroma. Genes significantly upregulated in theca interna compared to stroma includedINSL3,LHCGR,HSD3B1,CYP17A1,ALDH1A1,OGN,POSTNandASPN. Quantitative RT-PCR showed significantly greater expression ofOGNandLGALS1in interstitial stroma and theca interna versus tunica and greater expression ofACDin tunica compared to theca interna.PLNwas significantly higher in interstitial stroma compared to tunica and theca. Ingenuity pathway, network and upstream regulator analyses were undertaken. Cell survival was also upregulated in theca interna. The tunica albuginea was associated with GPCR and cAMP signalling, suggesting tunica contractility. It was also associated with TGF-β signalling and increased fibrous matrix. Western immunoblotting was positive for OGN, LGALS1, ALDH1A1, ACD and PLN with PLN and OGN highly expressed in tunica and interstitial stroma (eachn = 6), but not in theca interna from antral follicles (n = 24). Immunohistochemistry localised LGALS1 and POSTN to extracellular matrix and PLN to smooth muscle cells. These results have identified novel differences between the ovarian stromal compartments.

Ovary of the southern hairy-nosed wombat (Lasiorhinus latifrons): its divergent structural organisation

The organisation of the ovarian interstitial tissue in the southern hairy-nosed wombat Lasiorhinus latifrons was investigated. Unlike in most other marsupials, the outer cortical region of the ovary contains abundant luteinised interstitial tissue that largely occurs in discrete lobules, many of which contain a localised area of non-cellular, highly eosinophilic and periodic acid-Schiff-positive material. The findings suggest that the latter arises from the zona pellucida that surrounded the oocyte in growing follicles and that the luteinised interstitial tissue thus developed from transformed theca interna of degenerated atretic follicles. It is hypothesised that this tissue synthesises and secretes progestogens, which may result in the long, and variable, oestrous cycle length that has been found to occur in this species.

Histological description of aceh cattle ovary cryopreserved by various cryoprotectants

This research aimed to determine Aceh cattle ovarian follicle morphological integrity after vitrified by various cryoprotectants. Cryoprotectants used in this research were 30% ethylene glycol (EG), 30% dimethyl suphocide (DMSO), and combination of 15% EG + 15% DMSO. Prior to vitrification process, ovaries were cleansed by phosphate buffered saline (PBS) and then cut into ±1 mm³. Ovaries were consecutively submerged into the following liquid for 5 minutes each: PBS+ 0.25 M sucrose; PBS+ 0.5 M sucrose; PBS+ 0.5 M sucrose + 10% cryoprotectants; and PBS+ 0.5 M sucrose + 30% cryoprotectants. Then, ovaries were packed into straws with ±7 cm in length and ± 6 mm in diameter. Before kept in liquid nitrogen, ovaries were first exposed to nitrogen fume for 10 second. After being stored for 1 day, the ovaries were proceed for histological examination. The result showed that Aceh cattle ovarian follicle after vitrification using 30% EG yields the best morphological integrity. Cumulus oophorus, zona pellucida, granulose cell arrangement, theca interna, and theca externa cells were observed clearer in ovary which was vitrified with 30 % EG than those with 30% DMSO and combination of 15% EG + 15% DMSO. As conclusion, 30% EG was able to protect ovary morphological integrity better than 15 % EG + 15% DMSO and 30% DMSO. Furthermore, combination of 15% EG+ 15 % DMSO was relatively better in protecting ovary follicle morphological integrity compared to 30% DMSO.

The Influence of Testosterone on the Expression and Function of Vitamin D3 Receptor (VDR) Protein in the Porcine Ovarian Follicle

Recently it has been shown that vitamin D3 acting via its cognate receptor (VDR) regulates the growth, differentiation and function of female reproductive tissues including ovary. The aim of the study was to examine the effect of testosterone (T) and its antagonist 2-hydroxyflutamide (HF) on VDR protein expression and function in porcine ovarian follicles. Medium size antral follicles expressing great amount of androgen receptors and represent high steroidogenic activity were used in this research. After 6 h incubation of whole follicles with T, HF or T+HF, immunohistochemical analysis of VDR revealed its nuclear localization in granulosa and theca interna cells in control and experimental groups. The expression of VDR protein was shown as a band of 48 kDa. There were no significant differences between either experimental group and the control. T influenced the function of VDR through decreased formation of VDR/RXR (retinoid X receptor) complexes (P<0.05) in both granulosa and theca interna cells, but HF abolished this effect only in granulosa cells (P<0.05). These results suggest that androgens regulate the response of follicular cells to vitamin D3 in pigs ovary via regulation of VDR transcriptional activity.

Establishment of an in vitro culture model of theca cells from hierarchical follicles in ducks

Theca cells, including theca interna cells and theca externa cells, are vital components of ovarian follicles. The aim of the present study is to identify a reliable method for the in vitro culture of theca cells from duck ovarian hierarchical (F4-F2) follicles. We improved the method for cell separation by using trypsin to further remove granular cells, and we increased the concentration of fetal bovine serum used in in vitro culture to improve cytoactivity. Cell antibody immunofluorescence (IF) showed that all inoculated cells could be stained by the CYP17A1/19A1 antibody but not by the FSHR antibody, which could stain granulosa cells. Furthermore, morphological differences were observed between the outlines of theca interna and externa cells and in their nuclei. Growth curve and CYP17A1/19A1 mRNA relative expression analyses suggested that the growth profile of theca interna cells may have been significantly different from that of theca externa cells in vitro. Theca interna cells experienced the logarithmic phase on d1–d2, the plateau phase on d2–d3, and the senescence phase after d3, while theca externa cells experienced the logarithmic phase on d1–d3, the plateau phase on d3–d5, and the senescence phase after d5. Taken together, these results suggested that we have successfully established a reliable theca cell culture model and further defined theca cell characteristics in vitro.