Addition of synthetic polymer in the freezing solution of mesenchymal stem cells from equine adipose tissue as a future perspective for reducing of DMSO concentration.

The regenerative therapies with stem cells (SC) has been increased by the cryopreservation, permitting cell storage for extended periods. However, the permeating cryoprotectant agents (CPAs) such as dimethylsulfoxide (DMSO) can cause severe adverse effects. Therefore, this study evaluated equine mesenchymal stem cells derived from adipose tissue (eAT-MSCs) in fresh (Control) or after slow freezing (SF) in different freezing solutions (FS). The FS comprise DMSO and non-permeating CPAs [Trehalose (T) and the SuperCool X-1000 (X)] in association or not, totalizing seven different FS: (DMSO; T; X; DMSO+T; DMSO+X; T+X, and DMSO+T+X). Before and after cryopreservation were evaluated, viability, colony forming unit (CFU), and cellular differentiation capacity. After freezing-thawing, the viability of the eAT-MSCs reduced (P< 0.05) in all treatments compared to the control. However, the viability of frozen eAT-MSCs in DMSO (80.3 ± 0.6) was superior (P<0.05) to the other FS. Regarding CFU, no difference (P>0.05) was observed between fresh and frozen cells. After freezing-thawing, the eAT-MSCs showed osteogenic, chondrogenic, and adipogenic lineages differentiation potential. Nonetheless, despite the significative reduction in the osteogenic differentiation capacity between fresh and frozen cells, no differences (P > 0.05) were observed among FS. Furthermore, the number of chondrogenic differentiation cells frozen in DMSO+X solution reduced (P<0.05) comparing to the control, without differ (P>0.05) to the other FS. The adipogenic differentiation did not differ (P>0.05) among treatments. In conclusion, although these findings confirm the success of DMSO to cryopreserve eAT-MSCs, the Super Cool X-1000 could be a promise to reduce the DMSO concentration in a FS.

As terapias regenerativas com células-tronco (CT) têm sido incrementadas pela criopreservação, permitindo o armazenamento celular. No entanto, os agentes crioprotetores (ACPs) penetrantes, como DMSO, podem causar efeitos adversos graves. Portanto, este estudo avaliou células-tronco mesenquimais equinas derivadas de tecido adiposo (CTM-TAe) in natura (Controle) ou após congelamento lento (CL) em diferentes soluções de congelamento (SC). As SCs compreendem DMSO e ACPs não permeáveis [Trealose (T) e o SuperCool X-1000 (X)] associados ou não: (DMSO; T; X; DMSO+T; DMSO+X; T +X e DMSO+T+X). Antes e após a criopreservação foram avaliados, viabilidade, unidade formadora de colônia (UFC) e capacidade de diferenciação celular. Após o congelamento-descongelamento, a viabilidade das CTM-TAe reduziu (P< 0,05) em todos os tratamentos em relação ao controle. Entretanto, a viabilidade das CTM-TAe congeladas em DMSO (80,3 ± 0,6) foi superior (P<0,05) às demais SC. Em relação às UFC, não houve diferença (P>0,05) entre células frescas e congeladas. Após congelamento-descongelamento, as CTM-TAe apresentaram potencial de diferenciação de linhagens osteogênicas, condrogênicas e adipogênicas. No entanto, apesar da redução significativa na capacidade de diferenciação osteogênica entre células frescas e congeladas, não foram observadas diferenças (P > 0,05) entre SCs. Além disso, o número de células de diferenciação condrogênica congeladas em solução de DMSO+X reduziu (P<0,05) em relação ao controle, sem diferir (P>0,05) das demais SCs. A diferenciação adipogênica não diferiu (P>0,05) entre os tratamentos. Em conclusão, embora esses achados confirmem o sucesso do DMSO para criopreservar CTM-TAe, o Super Cool X-1000 pode ser uma promessa para reduzir a concentração de DMSO.

Development of sheep secondary follicles and preservation of aromatase and metalloproteinases 2 and 9 after vitrification and in vitro culture.

The cryopreservation of secondary follicles (SF) is a promising alternative to preserve the reproductive potential both in humans and animals in situations in which the transplantation of ovarian tissue is not possible. The objective of the present study was cryopreserved SF isolated sheep. Beyond follicular morphology, viability and development, we investigated proteins related to steroidogenic function and basement membrane remodeling [metalloproteinases 2 (MMP-2) and 9 (MMP-9)] in fresh SF (FSF) and vitrified SF (VSF) followed by in vitro culture for 6 (D6) or 12 days (D12). The percentage of intact follicles, follicular and oocyte diameter of the VSF were lower than FSF on both days of culture (P < 0.05). The VSF viability was statistically reduced from D6 (95.5%) to D12 (77.3%) but did not differ from the FSF on both days (D6:96.2% to D12:86.5%). Antrum formation in the VSF (D6: 59.13%; D12: 79.56%) was significantly lower than the FSF (D6: 79.61%; D12: 92.23%). However, an increase in this percentage was observed from D6 to D12 in both groups. Aromatase showed stronger labeling on FSF D6 and VSF D12 compared to other treatments (P < 0.05). MMP-2 showed a similar pattern of labeling in FSF D6 and VSF D12, similarly to that observed in FSF D12 and VSF D6. MMP-9 was similar in FSF and VSF cultivated for 6 and 12 days. In conclusion, VSF are able to grow and develop during 12 days of in vitro culture and showed evidence of preservation of steroidogenic function and remodeling of the basement membrane.

Vitrification of canine ovarian tissue using the Ovarian Tissue Cryosystem (OTC) device.

The present study evaluated the effect of Ovarian Tissue Cryosystem (OTC) on follicular morphology and density, as well as on stromal cell density of vitrified canine ovarian tissue. Canine ovarian fragments collected from adult female dogs in stages of the random oestrous cycle were fixed (FC, fresh control) or vitrified (VIT) with an OTC device. After vitrification and warming, the fragments were fixed for histological analysis. Overall, the mean percentage of normal pre-antral follicles decreased after vitrification procedure (FC: 74.5% ± 1.6% vs. VIT: 52.05% ± 1.5%). Although the rates of normal primordial (71.1% ± 1.8%) and secondary (0.7% ± 0.4%) follicles vitrified showed a reduction (p < .05), vitrification using OTC showed considerable preservation of follicles, when compared to the fresh control (81.1% ± 1.5% and 2.3% ± 0.6%, respectively). The mean follicular density was maintained after vitrification (FC: 199.65 ± 12.8 vs. VIT: 199.68 ± 10.8), whereas the stromal cell density decreased in the VIT group. Based on the results, we recommend the use of OTC for vitrification of canine ovarian tissue.

Alpha Lipoic Acid Supplementation Improves Ovarian Tissue Vitrification Outcome: An Alternative to Preserve the Ovarian Function of Morada Nova Ewe.

This study evaluated the effect of adding alpha lipoic acid (ALA) to the vitrification solution of sheep ovarian tissue on 7 days of in vitro culture or 15 days of xenotransplantion. ALA was used at two different concentrations (100 µM: ALA100 and 150 µM: ALA150). Ovarian tissue was evaluated by classical histology (follicular morphology, development, and stromal cell density); immunohistochemistry for forkhead box O3a (FOXO3a); Ki67 (cell proliferation); cluster of differentiation 31 (CD31); and alpha smooth muscle actin (α-SMA). Reactive oxygen species (ROS) levels in ovarian tissue, as well as malondialdehyde (MDA) and nitrite levels in the culture medium, were assessed. Similar percentage of morphologically normal follicles was found in the vitrified ovarian tissue in the presence of ALA100 or ALA150 after in vitro culture or xenotransplantation. Follicular development from all treatments was higher (P < 0.05) than the control group. Moreover, an activation of primordial follicles was observed by FOXO3a. Stromal cell density and immunostaining for Ki67 and CD31 were significantly higher (P < 0.05) in ALA150 vitrified tissue. No difference (P > 0.05) was found in α-SMA between ALA concentrations after in vitro culture or xenograft. ROS levels in the ovarian tissue were similar (P > 0.05) in all treatments, as well as MDA and nitrite levels after 7 days of culture. We concluded that the addition of ALA 150 is able to better preserve the stromal cell density favoring granulosa cell proliferation and neovascularization.

Equine ovarian tissue xenografting: impacts of cooling, vitrification, and VEGF.

Ovarian tissue transplantation methods using cooled and cryopreserved samples have been attractive options for fertility preservation in animal models and humans. The aim of this study was to evaluate the impact of previous exposure to cooling, cryopreservation, and VEGF on the overall efficiency of equine ovarian tissue after heterotopic xenotransplantation in mice. The end points evaluated were follicular morphology and development, follicular and stromal cell densities, angiogenesis (i.e. the density of new and mature blood vessels), collagen types I and III fiber densities, and total fibrosis. Ovaries of adult mares were harvested after ovariectomy, and ovarian fragments were xenografted in the i.p. wall of BALB nude mice. Ten types of treatments involving different combinations of cooling, cryopreservation, xenografting procedures, and VEGF exposure were compared. The novel aspect of this study was the use of equine ovarian tissue xenotransplantation in mice, challenging the fragments with different combinations of treatments. The main findings were (i) cooling but not cryopreservation was effective in preserving the follicular morphology, (ii) a greater percentage of developing follicles but lower follicular and stromal cell densities were observed after ovarian tissue engraftment, (iii) exposure to VEGF increased new and mature vessels in cryopreserved-transplanted tissue, and (iv) an appropriate balance in the collagen types I and III fiber ratio in cooling-transplanted tissue was observed after exposure to VEGF. This study contributes to advancing knowledge in the preservation of ovarian tissue after cooling-cryopreservation and transplantation aiming to be applied to genetically superior/valuable horses, livestock, endangered animals, and, possibly, humans. LAY SUMMARY: Due to ethical limitations involving humans, the female horse (mare) has recently emerged as an alternative model for reproductive comparisons with women to optimize fertility restoration using ovarian tissue transplantation techniques. This study determined if ovarian tissue from donor mares (n = 3), exposed or not to vascular endothelial growth factor (VEGF) before transplantation, better survives for 7 days after transplantation into mouse hosts (n = 12). Tissues submitted to different combinations of cooling, freezing, and transplanting treatments, along with control groups, were evaluated using the parameters morphology, development, the density of immature eggs (follicles), the density of supportive (stromal) cells, collagen protein proportions, and density of blood vessels. Frozen-thawed treatments had lower percentages of normal follicles. Exposure to VEGF increased blood vessel densities in frozen tissue and favored adequate collagen levels in cooled-transplanted treatments. In conclusion, VEGF exposure seems to be beneficial for mare ovarian tissue transplantation and warrants further investigation.

Vitrification of caprine secondary and early antral follicles as a perspective to preserve fertility function.

The present study aimed to evaluate the structure, survival and development of isolated caprine (secondary-SEC and early antral-EANT) follicles, after vitrification in the presence of synthetic polymers and in vitro culture. Additionally, transzonal projections (TZPs) and p450 aromatase enzyme were evaluated. After isolation, SEC and EANT follicles were in vitro cultured for six days or vitrified. After one week, SEC and EANT follicles were warmed and also in vitro cultured for six days. Data revealed that the percentage of morphologically normal follicles was similar between fresh and vitrified follicles in both follicular categories and antrum formation rate was similar between fresh and vitrified SEC follicles. Fluorescence by calcein-AM did not show difference between fresh and vitrified (SEC and EANT) follicles, however, the trypan blue test showed low viability for vitrified follicles. The integrity of TZPs was not affected between fresh and vitrified SEC follicles, however, in vitrified EANT follicles, there were signs of TZPs loss. Regarding steroidogenic function, it was observed a positive staining for p450 aromatase enzyme in fresh and vitrified SEC and EANT follicles. It was concluded that SEC follicles seem to be more resistant to vitrification than EANT follicles, as shown by the trypan blue test and TZPs assay. Future studies may confirm this hypothesis, in order to consolidate the use of SEC and EANT follicles as an alternative to ovary cryopreservation.

Equol: A Microbiota Metabolite Able to Alleviate the Negative Effects of Zearalenone during In Vitro Culture of Ovine Preantral Follicles.

The impact of zearalenone (ZEN) on female reproduction remains an issue, since its effects may differ among exposed cell types. Besides the use of decontaminants in animal diet, other approaches should be considered to minimise ZEN effects after exposure. Since the first organ in contact with ZEN is the gastrointestinal tract, we hypothesise that products of microbiota metabolism may play a role in ZEN detoxification. We aimed to evaluate the effect of 1 µmol/L ZEN and 1 µmol/L equol (a microbial metabolite), alone or in combination, on the survival and morphology of in vitro cultured ovarian preantral follicles. Ovaries from 12 sheep were collected at a local abattoir and fragmented, and the ovarian pieces were submitted to in vitro culture for three days in the presence or absence of the test compounds. The follicular morphology was impaired by ZEN, but equol could alleviate the observed degeneration rates. While ZEN decreased cell proliferation in primary and secondary follicles, as well as induced DNA double-strand breaks in primordial follicles, all these observations disappeared when equol was added to a culture medium containing ZEN. In the present culture conditions, equol was able to counteract the negative effects of ZEN on ovarian preantral follicles.

Natural antioxidants in the vitrification solution improve the ovine ovarian tissue preservation.

The present study evaluated the effect of the addition of antioxidants anethole (AN) and robinin (RO) in the vitrification solution, and the in vitro incubation (IVI) medium of ovine ovarian tissue. Ovarian fragments were vitrified without antioxidant (VWA) or with different concentrations of AN (30, 300 and 2000 µg/mL) or RO (0.125, 0.25 and 0.50 mg/mL), followed by IVI (24 h). Histological analyses showed that the percentage of morphologically normal preantral follicles (MNPF) in AN 2000 did not differ from RO 0.125 or fresh ovarian tissue (CTR). Subsequently, ovarian fragments were vitrified in the presence of AN 2000 and RO 0.125 followed by IVI without or with (AN 2000+ and RO 0.125+) the same antioxidants. The follicular activation in all treatments was significantly increased as compared to the CTR. The stroma cell density (SCD) in all the vitrified fragments was significantly lower than the CTR. However, in the AN 2000 and RO 0.125 this parameter was significantly higher when compared to the VWA. The reactive oxygen species (ROS) in the ovarian cortex of the AN 2000 or AN 2000+ were significantly reduced in comparison with the CTR while the intracellular ROS levels of AN 2000 and CTR were similar. The total antioxidant capacity (TAC) in RO 0.125 was significantly higher than that of VWA, AN 2000 and AN 2000+. According to the results, the use of antioxidants (AN or RO) only in the vitrification solution of ovine ovarian tissue is recommended, due to their better preservation of the SCD. Moreover, AN 2000 best maintains the follicular morphology, while RO 0.125 has a high TAC.