Involvement of Matrix Metalloproteinases and their Inhibitors in Bovine Cystic Ovarian Disease

Concentrations of matrix metallopeptidase 9, interleukin 4, and interleukin 8 in follicular fluid, and the results of in vitro fertilization

Objective

Cytokines and enzymes in follicular fluid (FF) may have a crucial role in fertility. This study aimed to analyse the results of in vitro fertilization/embryo transfer (IVF/ET) and compare them with matrix metalloproteinase 9 (MMP-9) and cytokine concentrations in FF.

Methods

This case–control study included 20 randomly selected patients with a positive pregnancy (PPG) test and 20 with a negative pregnancy (NPG) test after IVF/ET. In FF obtained during oocyte retrieval, the concentrations of soluble forms of MMP-9, interleukin 1 (IL-1) alpha, IL-1 beta, interferon gamma, IL-2, IL-4, IL-6, IL-8, and IL-10 were measured. Their effect on the characteristics of follicles, embryos, and the efficiency of IVF and ET were analysed.

Results

High-sensitivity IL-4 concentrations were significantly higher in patients with a PPG test than in those with an NPG test (3.15 ± 3.23 vs 1.91 ± 0.35 pg/mL). The number of top-quality embryos achieved was significantly higher in patients with a PPG test than in those with an NPG test (2.6 ± 1.39 vs 1.75 ± 1.21), and they were negatively correlated with IL-8 concentrations in FF.

Conclusion

Further research on the role of IL-4 and IL-8 in FF is required to establish any clinical benefit of determining their concentrations in FF of infertile women.

The expression and localization of selected matrix metalloproteinases (MMP-2, -7 and -9) and their tissue inhibitors (TIMP-2 and -3) in follicular cysts of sows

Matrix metalloproteinases (MMPs) are a family of enzymes that degrade extracellular matrix (ECM) molecules, playing a vital role in tissue remodeling under physiological and pathological conditions. Their expression and/or activity are regulated by specific tissue inhibitors of MMPs named TIMPs. Recently, an imbalance in the MMP/TIMP system has been found in human and bovine ovarian cysts, but its role in porcine cyst pathogenesis is unknown. This study examined mRNA expression, protein abundance and localization for selected members of the MMP/TIMP system in follicular cysts of sows. Based on histological analysis, we have assessed follicular (FC) and follicular lutein (FLC) cysts with preovulatory follicles (PF) used as a control. Regarding the pattern of MMP expression, increased MMP2, MMP7 and MMP9 mRNA levels were observed in FLC. Furthermore, both pro- and active forms of MMP-2 and MMP-9 proteins were more abundant in FLC. In FC, the abundance of latent and active forms of MMP-9 and the active form of MMP-2 were greater when compared with PF. In relation to TIMPs, TIMP-2 mRNA and protein expression were increased in FLC, whereas TIMP-3 was up-regulated in both FC and FLC only at the protein level. Using immunofluorescence, MMP-2, MMP-7, TIMP-2 and TIMP-3 were detected in granulosa and theca compartments of FC and within the entire luteinized wall of FLC. Notably, MMP-9 occurred weakly in the granulosa layer of FC, but abundantly in the theca compartment of FC and in the luteinized FLC. Taken together, our findings indicate altered expression of the MMP/TIMP system, suggestive of increased ECM degradation, in sow follicular cysts. These components may be involved in the pathogenesis of porcine ovarian cysts through the ECM remodeling.

Effects of different cyclooxygenase inhibitors on prostaglandin E₂ production, steroidogenesis and ovulation of bovine preovulatory follicles

Ovulation is an inflammation-like process, and cyclooxygenase-2 (COX-2)-dependent production of prostaglandin E₂ (PGE₂) is its key mediator. Balanced regulation of inflammatory processes in high-yielding dairy cows may be essential for physiological ovulation and fertility. This study aimed to elucidate the mechanisms underlying ovulation failure and cyst development after disturbing intrafollicular inflammatory cascades. Therefore, nonselective (indomethacin and flunixin-meglumine), COX-2 selective (meloxicam), and highly COX-2 selective (NS-398) inhibitors were injected into preovulatory follicles 16 h after administration of GnRH, and ovulation was monitored via ultrasound examination. Additionally, follicular fluid was collected after injection of indomethacin, meloxicam, and NS-398. Moreover, primary granulosa cell cultures from preovulatory follicles were prepared and treated with indomethacin, meloxicam, and NS-398. The concentrations of 17β-estradiol, progesterone, and prostaglandin E₂ (PGE₂) in the follicular fluid and cell supernatant were estimated. Indomethacin and flunixin-meglumine blocked ovulation, even at low doses, and led to ovarian cyst development. The selective and highly selective COX-2 inhibitors meloxicam and NS-398 were not effective in blocking ovulation. However, indomethacin, meloxicam, and NS-398 significantly and comparably reduced PGE₂ concentration in vivo and in vitro (P < 0.05) but had no effect on estradiol or progesterone production. This may contradict the generally accepted hypothesis that PGE₂ is a key mediator of ovulation and progesterone production. Our results suggest a connection between ovarian disorders and inflammatory actions in early postpartum cows.

MC2R/MRAP2 activation could affect bovine ovarian steroidogenesis potential after ACTH treatment

Stressors activate the hypothalamic-pituitary-adrenal (HPA) axis, reducing fertility by interfering with the mechanisms that regulate the timing of events within the follicular phase of the estrous cycle. In the HPA axis, melanocortin 2 receptor (MC2R) mediates responses to adrenocorticotropic hormone (ACTH) in concert with melanocortin receptor accessory protein 2 (MRAP2). The aims of the present study were: (1) to evaluate the effects of ACTH administered in cows in the preovulatory period on the expression of the MC2R/MRAP2 complex in the dominant follicle; and (2) to analyze the involvement of Extracellular signal Regulated Kinase 1 (ERK1) signaling in the activation of MC2R and the expression of key enzymes involved in the biosynthesis of glucocorticoids (GCs) in the dominant follicle. To this end, 100 IU ACTH was administered to Holstein cows from a local dairy farm during pro-estrus every 12 h for four days until ovariectomy, which was performed before ovulation. Protein immunostaining of MC2R was higher in the dominant follicles of ACTH-treated cows (p < 0.05). Also, Western blot analysis showed higher activation of the ERK1 signaling pathway in ACTH-treated cows (p < 0.05). Finally, immunohistochemistry performed in the dominant follicles of ACTH-treated cows detected higher expression of CYP17A1 and CYP21A2 (p < 0.05). These results suggest that the bovine ovary is able to respond locally to ACTH as a consequence of stress altering the expression of relevant steroidogenic enzymes. The results also confirm that the complete GC biosynthesis pathway is present in bovine dominant follicle and therefore GCs could be produced locally.

Effects of adrenocorticotrophic hormone on the expression of matrix metalloproteinases and their inhibitors in the bovine ovary

Cattle undergo numerous environmental and management stressors that reduce fertility and affect ovulation. The extracellular matrix of the follicle wall can be altered by matrix metalloproteinases (MMPs), the activities of which are regulated by interleukins and tissue-specific inhibitors of metalloproteinases (TIMPs), especially during ovulation. The aims of the present study were to: (1) evaluate changes in the hormone milieu, the localisation and activity of MMP2 and MMP9 and the localisation of MMP14, TIMP1 and TIMP2 in response to adrenocorticotrophic hormone (ACTH) during the preovulatory period in cows; and (2) determine the direct effects of ACTH on the mRNA expression of MMP2 and MMP9 in the cultured follicle wall of bovine ovaries obtained from an abattoir. 100IU ACTH was administered during pro-oestrus every 12h until ovariectomy, which was performed before ovulation. Cortisol concentrations in the plasma and follicular fluid (FF) of preovulatory follicles were higher in ACTH-treated than control cows. Progesterone presented subluteal concentrations in plasma of ACTH-treated cows (P<0.05). MMP2 immunostaining and activity in ovaries were higher in ACTH-treated than control cows (P<0.05), whereas MMP9 immunostaining was similar between the two groups. However, unlike in control cows, MMP9 activity was absent in the FF of ACTH-treated cows. These results suggest that the administration of ACTH during the preovulatory period in cows could cause changes that culminate in modifications in the content and activation of MMPs and TIMPs in the ovary, which could interfere with the ovulation process.

Ovarian cysts, an anovulatory condition in dairy cattle

Ovarian cysts are one of the most common ovarian dysfunctions in dairy cattle, which can lead to a considerable economic loss through its high incidence and can reduce the reproductive performance. Anestrus is the most significant clinical sign observed in dairy cattle suffering from this condition. For diagnosis, most of the veterinarians use a combination of methods, from ultrasonography as an additional approach to trans-rectal palpation and symptomatology when assessing ovarian cysts. Although the Ovsynch treatment seems to be preferred, the pregnancy rate after this treatment is relatively low. Despite such reports on dairy cattle ovarian cysts, the data is insufficient to validate all the characteristics of this condition. This review summarizes what the literature has so far provided from definition to treatment of ovarian cysts in dairy cattle.

Crosstalk between Neospora caninum and the bovine host at the maternal-foetal interface determines the outcome of infection

Neospora caninum is an apicomplexan cyst-forming parasite that is considered one of the main causes of abortion. The pathogenic mechanisms associated with parasite virulence at the maternal-foetal interface that are responsible for the outcome of infection are largely unknown. Here, utilizing placentomes from cattle experimentally infected with high-virulence (Nc-Spain7) and low-virulence (Nc-Spain1H) isolates, we studied key elements of the innate and adaptive immune responses, as well as components of the extracellular matrix (ECM), at 10 and 20 days post-infection (dpi). The low-virulence isolate elicited a robust immune response characterized by upregulation of genes involved in pathogen recognition, chemokines and pro-inflammatory cytokines, crucial for its adequate control. In addition, Nc-Spain1H triggered the expression of anti-inflammatory cytokines and other mechanisms implicated in the maintenance of ECM integrity to ensure foetal survival. In contrast, local immune responses were initially (10 dpi) impaired by Nc-Spain7, allowing parasite multiplication. Subsequently (20 dpi), a predominantly pro-inflammatory Th1-based response and an increase in leucocyte infiltration were observed. Moreover, Nc-Spain7-infected placentomes from animals carrying non-viable foetuses exhibited higher expression of the IL-8, TNF-α, iNOS and SERP-1 genes and lower expression of the metalloproteases and their inhibitors than Nc-Spain7-infected placentomes from animals carrying viable foetuses. In addition, profound placental damage characterized by an alteration in the ECM organization in necrotic foci, which could contribute to foetal death, was found. Two different host-parasite interaction patterns were observed at the bovine placenta as representative examples of different evolutionary strategies used by this parasite for transmission to offspring.