scholarly journals Comparison of bioactivities, binding properties and intrafollicular levels of bovine follistatins

Reproduction ◽  
2015 ◽  
Vol 150 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Claire Glister ◽  
Simon J Sunderland ◽  
Maurice P Boland ◽  
James J Ireland ◽  
Phil G Knight
Keyword(s):  
Heparan Sulphate ◽  
Activin A ◽  
Follicle Development ◽  
Binding Properties ◽  
Follicular Waves ◽  
Positive Effects ◽  
Follicle Diameter ◽  
Negative Role ◽  
And Function

Five isoforms of follistatin (FST) (Mr31, 33, 35, 37, and 41 kDa) were purified from bovine follicular fluid (bFF). Comparison of their activin and heparan sulphate proteoglycan (HSP) binding properties and biopotencies in the neutralisation of activin A actionin vitrorevealed that all five isoforms bound activin A, but they did so with different affinities. Only the 31 kDa isoform (FST-288) bound to HSP. FST-288 also showed the greatest biopotency, and the 35 and 41 kDa isoforms were the least potent. To determine whether bovine follicle development is associated with changing intrafollicular FST and activin profiles, we analysed bFF from dominant follicles (DFs) and subordinate follicles (SF) collected at strategic times during a synchronised oestrous cycle. Total FST, activin A and activin AB were measured by immunoassay, whereas individual FST isoforms were quantified by immunoblotting. Follicle diameter was positively correlated with oestrogen:progesterone ratio (r=0.56) in bFF but negatively correlated with activin A (r=−0.34), activin AB (r=−0.80) and ‘total’ FST (r=−0.70) levels. Follicle diameter was positively correlated with the abundance of the 41 kDa isoform (r=0.59) but negatively correlated with the abundance of the 33 and 31 kDa isoforms (r=−0.56 andr=−0.41 respectively). Both follicle statuses (DF and SF) and cycle stage affected total FST, activin A and activin B levels, whereas follicle status, but not cycle stage, affected the abundance of the 41, 37, 33 and 31 kDa FST isoforms. Collectively, these findings indicate that intrafollicular FST isoforms, which differ in their ability to bind and neutralise activins and to associate with cell-surface proteoglycans, show divergent changes during follicle development. Enhanced FST production may play an important negative role, either directly or via the inhibition of the positive effects of activins, on follicle growth and function during follicular waves.

scholarly journals Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Reproduction ◽  
2007 ◽  
Vol 133 (6) ◽  
pp. 1121-1128 ◽  
Author(s):  
Fiona H Thomas ◽  
Bruce K Campbell ◽  
David G Armstrong ◽  
Evelyn E Telfer
Keyword(s):  
Follicular Development ◽  
Follicle Development ◽  
Dependent Manner ◽  
Igf Binding Proteins ◽  
Preantral Follicles ◽  
Follicle Diameter ◽  
Igf I ◽  
Igf Binding ◽  
Development In Vitro

The aim of this study was to determine the effect of regulation of IGF-I bioavailability on preantral follicle development in vitro. Bovine preantral follicles were cultured for 6 days in serum-free medium with increasing doses of Long R3 (LR3) IGF-I (an analog with low affinity for IGF-binding proteins (IGFBPs)), or human recombinant IGF-I (hrIGF-I). Follicle diameter and estradiol production were measured every second day. On day 6, ratios of oocyte/follicle diameter and oocyte morphology were assessed by histological examination, and IGFBP-2 and -3 were detected by immunocytochemistry and in situ hybridization respectively. Both types of IGF-I increased follicle diameter in a dose-dependent manner (P < 0.05) and increased estradiol production over control levels (P < 0.05). However, follicles treated with LR3 IGF-I and the highest concentration of hrIGF-I (1000 ng/ml) had smaller oocyte/follicle ratios, and increased oocyte degeneration, compared with controls or follicles treated with physiological concentrations of hrIGF-I (P < 0.05). IGFBPs were detected in cultured preantral follicles, indicating a requirement for regulation of IGF bioavailability during the early stages of follicular development. Specifically, IGFBP-3 mRNA was found to be expressed in oocytes, and IGFBP-2 immunoreactivity was detected in oocytes and granulosa cells of cultured follicles. In summary, the regulation of IGF-I bioavailability by IGFBPs is necessary for the co-ordination of oocyte and follicle development in vitro.

scholarly journals Dickkopf-1 Inhibition Reactivates Wnt/β-Catenin Signaling in Rhabdomyosarcoma, Induces Myogenic Markers In Vitro and Impairs Tumor Cell Survival In Vivo

2021 ◽  
Vol 22 (23) ◽  
pp. 12921
Author(s):  
Irina Giralt ◽  
Gabriel Gallo-Oller ◽  
Natalia Navarro ◽  
Patricia Zarzosa ◽  
Guillem Pons ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Positive Effects ◽  
Novel Therapeutic Strategies ◽  
And Function ◽  
Myogenic Markers ◽  
First Time ◽  
Dickkopf 1 ◽  
Proliferation And Invasion

The Wnt/β-catenin signaling pathway plays a pivotal role during embryogenesis and its deregulation is a key mechanism in the origin and progression of several tumors. Wnt antagonists have been described as key modulators of Wnt/β-catenin signaling in cancer, with Dickkopf-1 (DKK-1) being the most studied member of the DKK family. Although the therapeutic potential of DKK-1 inhibition has been evaluated in several diseases and malignancies, little is known in pediatric tumors. Only a few works have studied the genetic inhibition and function of DKK-1 in rhabdomyosarcoma. Here, for the first time, we report the analysis of the therapeutic potential of DKK-1 pharmaceutical inhibition in rhabdomyosarcoma, the most common soft tissue sarcoma in children. We performed DKK-1 inhibition via shRNA technology and via the chemical inhibitor WAY-2626211. Its inhibition led to β-catenin activation and the modulation of focal adhesion kinase (FAK), with positive effects on in vitro expression of myogenic markers and a reduction in proliferation and invasion. In addition, WAY-262611 was able to impair survival of tumor cells in vivo. Therefore, DKK-1 could constitute a molecular target, which could lead to novel therapeutic strategies in RMS, especially in those patients with high DKK-1 expression.

scholarly journals Activin B is produced early in antral follicular development and suppresses thecal androgen production

Reproduction ◽  
2012 ◽  
Vol 143 (5) ◽  
pp. 637-650 ◽  
Author(s):  
J M Young ◽  
S Henderson ◽  
C Souza ◽  
H Ludlow ◽  
N Groome ◽  
...  
Keyword(s):  
Follicular Development ◽  
Activin A ◽  
Mrna Levels ◽  
Negative Effects ◽  
Inhibin A ◽  
Protein Levels ◽  
Follicle Diameter ◽  
Preovulatory Follicles ◽  
Follicle Size

Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s).

scholarly journals The activin-follistatin system and in vitro early follicle development in goats

2006 ◽  
Vol 189 (1) ◽  
pp. 113-125 ◽  
Author(s):  
J R V Silva ◽  
T Tharasanit ◽  
M A M Taverne ◽  
G C van der Weijden ◽  
R R Santos ◽  
...  
Keyword(s):  
Ovarian Tissue ◽  
Primordial Follicle ◽  
Activin A ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Follicle Development ◽  
Cortical Tissue ◽  
Primary Follicle ◽  
Growth And Survival ◽  
Primordial Follicles

The aim of the present study was to investigate the effects of activin-A and follistatin on in vitro primordial and primary follicle development in goats. To study primordial follicle development (experiment 1), pieces of ovarian cortex were cultured in vitro for 5 days in minimal essential medium (MEM) supplemented with activin-A (0, 10 or 100 ng/ml), follistatin (0, 10 or 100 ng/ml) or combinations of the two. After culture, the numbers of primordial follicles and more advanced follicle stages were calculated and compared with those in non-cultured tissue. Protein and mRNA expression of activin-A, follistatin, Kit ligand (KL), growth differentiation factor-9 (GDF-9) and bone morphogenetic protein-15 (BMP-15) in non-cultured and cultured follicles were studied by immunohistochemistry and PCR. To evaluate primary follicle growth (experiment 2), freshly isolated follicles were cultured for 6 days in MEM plus 100 ng/ml activin-A, 100 ng/ml follistatin or 100 ng/ml activin-A plus 200 ng/ml follistatin. Morphology, follicle and oocyte diameters in cultured tissue and isolated follicles before and after culture were assessed. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) reactions were performed to study DNA fragmentation in follicles. In experiment 1, it was found that goat primordial follicles were activated to develop into more advanced stages, i.e. intermediate and primary follicles, during in vitro culture, but neither activin-A nor follistatin affected the number of primordial follicles that entered the growth phase. Activin-A treatment enhanced the number of morphologically normal follicles and stimulated their growth during cortical tissue culture. The effects were, however, not counteracted by follistatin. The follicles in cultured goat tissue maintained their expression of proteins and mRNA for activin-A, follistatin, KL, GDF-9 and BMP-15. Fewer than 30% of the atretic follicles in cultured cortical tissue had TUNEL-positive (oocyte or granulosa) cells. Activin-A did not affect the occurrence of TUNEL-positive cells in follicles within cortical tissue. In experiment 2, addition of activin-A to cultured isolated primary follicles significantly stimulated their growth, the effect being counteracted by follistatin. Absence of such a neutralizing effect of follistatin in the cultures with ovarian cortical tissue can be due to lower dose of follistatin used and incomplete blockage of activin in these experiments. In contrast to cortical enclosed atretic follicles, all atretic follicles that had arisen in cultures with isolated primary follicles had TUNEL-positive cells, which points to differences between isolated and ovarian tissue-enclosed follicles with regard to the followed pathways leading to their degeneration. In summary, this in vitro study has demonstrated that cultured goat primordial follicles are activated to grow and develop into intermediate and primary follicles. During in vitro culture, the follicles maintain their ability to express activin-A, follistatin, KL, GDF-9 and BMP-15. The in vitro growth and survival of activated follicles enclosed in cortical tissue and the in vitro growth of isolated primary follicles are stimulated by activin-A.

132. ACTIVIN A HAS A STIMULATORY EFFECT IN VITRO ON EARLY FOLLICLE DEVELOPMENT IN RAT OVARIES

2010 ◽  
Vol 22 (9) ◽  
pp. 50
Author(s):  
D. A. Cossigny ◽  
J. K. Findlay ◽  
A. E. Drummond
Keyword(s):  
Treatment Group ◽  
Real Time ◽  
Granulosa Cells ◽  
Combined Treatment ◽  
Activin A ◽  
Tunel Staining ◽  
Follicle Development ◽  
Primordial Follicles ◽  
Preantral Follicles

Activins are dimers of inhibin β subunits and are growth and differentiation factors belonging to the transforming growth factor-β (TGF-β) superfamily (1). Both βA and βB subunits are highly expressed in rat granulosa cells, while theca cells express little or no β subunit mRNAs (2). Oocytes lack expression of either subunit (3, 4). Activin is suggested to facilitate the responsiveness of granulosa cells to FSH (5). We hypothesized that activin, with or without FSH, could enhance the transition from the primordial to later preantral stages of follicle development. In two independent experiments, day 4 rat ovaries (n = 3 from different rats per treatment) were randomly assigned and cultured (6, 7) for 10 days in DMEM/Hams F-12 media with either no additives, FSH (100 ng/mL), activin A (50 ng/mL), or both. Day 4 fresh ovaries were also used as controls. Media and treatments were refreshed every alternate day. Ovaries were fixed andsectioned, or placed into Ultraspec for RNA extraction and real-time PCR analysis. Follicle numbers were counted as described previously (7). The proportion of atretic follicles (TUNEL staining) was determined in 3 randomly selected sections per ovary. Primordial follicles in all treatment groups were approximately 20% of those in Day 4 fresh ovaries. Primary follicles increased significantly (P < 0.05) only in the combined treatment group, where preantral follicles increased significantly (P < 0.0001) only when treated with activin A alone. Activin A alone decreased the proportion of atretic follicles in the primary and preantral classes, where the combined treatment increased the proportion of atretic preantral follicles. Real-time analysis revealed that expression levels of follistatin, FSH receptor and activin βA and βB subunits were all expressed at significantly higher levels in the Activin A-only treated group (P < 0.05). In summary, there was no effect on primordial follicle activation by any treatment. Activin alone had a stimulatory effect in vitro on subsequent folliculogenesis, but in the presence of FSH its effect was counteracted shown by an increase in atresia. Reasons for an increase in atretic preantral follicles in the combined treatment group are unclear. These studies support a stimulatory role for activin A in early follicle development and confirm the in vivo effects of activin on folliculogenesis (4). NHMRC program grant # 494802 and Fellowship (# 441101) provided financial support. (1) Vale W et al. 1986. Nature 321: 776–779.(2) Meunier H et al. 1988. Proc Natl Acad Sci USA 85: 547–251.(3) Roberts V et al. 1993. Journal of Clinical Endocrinology & Metabolism 7: 1402–1410.(4) Sidis Y et al. 1998. Biology of Reproduction 59(4): 807–812.(5) Drummond A et al. 2002. Endocrinology 143 (4): 1423–1433.(6) Nilsson E et al. 2001. Molecular and Cellular Endocrinology 182 (2): 145–155.(7) Rosairo D et al. 2008. Reproduction 136: 799–809.

scholarly journals Microglia-Derived Exosomes Improve Spinal Cord Functional Recovery after Injury via Inhibiting Oxidative Stress and Promoting the Survival and Function of Endothelia Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Wei Peng ◽  
Liyang Wan ◽  
Zixiang Luo ◽  
Yong Xie ◽  
Yudong Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Spinal Cord ◽  
Mouse Model ◽  
Functional Recovery ◽  
Protein Levels ◽  
Positive Effects ◽  
Vascular Regeneration ◽  
Cord Injury ◽  
And Function

Traumatic spinal cord injury (SCI) is a devastating disease of the central nervous system with long-term disability and high mortality worldwide. Revascularization following SCI provides nutritional supports to rebuild and maintain the homeostasis of neuronal networks, and the subsequent promotion of angiogenesis is beneficial for functional recovery. Oxidative stress drastically produced following SCI has been contributed to endothelial dysfunction and the limited endogenous repair of microvasculature. Recently, exosomes, being regarded as potential therapeutic candidates for many kinds of diseases, have attracted great attentions due to its high bioavailability, safety, and stability. Microglia have been reported to exhibit proangiogenic function and guide the forming of vasculature during tissue repair. However, the specific role of microglia-derived exosomes (MG-Exos) played in SCI is still largely unknown. In the present study, we aimed to evaluate whether MG-Exos could protect spinal cord microvascular endothelial cells (SCMECs) against the toxic effects of oxidative stress, thus promote SCMECs’ survival and function. We also investigated the protective effects of MG-Exos in the mouse model of SCI to verify their capability. Our results demonstrated that MG-Exo treatment significantly decreased the level of oxidative stress (ROS), as well as did the protein levels of NOX2 when bEnd.3 cells were exposed to H2O2-induced oxidative stress in vitro and in vivo. Functional assays showed that MG-Exos could improve the survival and the ability of tube formation and migration in H2O2-induced bEnd.3 in vitro. Moreover, MG-Exos exhibited the positive effects on vascular regeneration and cell proliferation, as well as functional recovery, in the mouse model of SCI. Mechanically, the keap1/Nrf2/HO-1 signaling pathway was also investigated in order to unveil its molecular mechanism, and the results showed that MG-Exos could increase the protein levels of Nrf2 and HO-1 via inhibiting the keap1; they also triggered the expression of its downstream antioxidative-related genes, such as NQo1, Gclc, Cat, and Gsx1. Our findings indicated that MG-Exos exerted an antioxidant effect and positively modulated vascular regeneration and neurological functional recovery post-SCI by activating keap1/Nrf2/HO-1 signaling.

scholarly journals Ovarian follicle development in the laying hen is accompanied by divergent changes in inhibin A, inhibin B, activin A and follistatin production in granulosa and theca layers

2003 ◽  
Vol 177 (1) ◽  
pp. 45-55 ◽  
Author(s):  
TM Lovell ◽  
RT Gladwell ◽  
NP Groome ◽  
PG Knight
Keyword(s):  
Functional Role ◽  
Ovarian Follicle ◽  
Fold Increase ◽  
Activin A ◽  
Inhibin B ◽  
Follicle Development ◽  
Inhibin A ◽  
Ovarian Follicle Development ◽  
Tissue Extracts

To study the potential involvement of inhibin A (inhA), inhibin B (inhB), activin A (actA) and follistatin (FS) in the recruitment of follicles into the preovulatory hierarchy, growing follicles (ranging from 1 mm to the largest designated F1) and the three most recent postovulatory follicles (POFs) were recovered from laying hens (n=11). With the exception of <4 mm follicles and POFs, follicle walls were dissected into separate granulosa (G) and theca (T) layers before extraction. Contents of inhA, inhB, actA and FS in tissue extracts were assayed using specific two-site ELISAs and results are expressed per mg DNA. InhB content of both G and T followed a similar developmental pattern, although the content was >4-fold higher in G than in T at all stages. InhB content was very low in follicles <4 mm but increased ~50-fold (P<0.0001) to peak in 7-9 mm follicles, before falling steadily as follicles entered and moved up the follicular hierarchy (40-fold; 8 mm vs F2). In stark contrast, inhA remained very low in prehierarchical follicles (< or =9 mm) but then increased progressively as follicles moved up the preovulatory hierarchy to peak in F1 (approximately 100-fold increase; P<0.0001); In F1 >97% of inhA was confined to the G layer whereas in 5-9 mm follicles inhA was only detected in the T layer. Both inhA and inhB contents of POFs were significantly reduced compared with F1. Follicular actA was mainly confined to the T layer although detectable levels were present in G from 9 mm; actA was low between 1 and 9 mm but increased sharply as follicles entered the preovulatory hierarchy (approximately 6-fold higher in F4; P<0.0001); levels then fell approximately 2-fold as the follicle progressed to F1. Like actA, FS predominated in the T although significant amounts were also present in the G of prehierarchical follicles (4-9 mm), in contrast to actA, which was absent from the G. The FS content of T rose approximately 3-fold from 6 mm to a plateau which was sustained until F1. In contrast, the FS content of G was greatest in prehierarchical follicles and fell approximately 4-fold in F4-F1 follicles. ActA and FS contents of POFs were reduced compared with F1. In vitro studies on follicle wall explants confirmed the striking divergence in the secretion of inhA and inhB during follicle development. These findings of marked stage-dependent differences in the expression of inhA, inhB, actA and FS proteins imply a significant functional role for these peptides in the recruitment and ordered progression of follicles within the avian ovary.

First pregnancy after in vitro culture of early antral follicles in goats: Positive effects of anethole on follicle development and steroidogenesis

2020 ◽  
Vol 87 (9) ◽  
pp. 966-977
Author(s):  
Naiza A. R. Sá ◽  
Anna C. A. Ferreira ◽  
Francisca G. C. Sousa ◽  
Ana B. G. Duarte ◽  
Victor. M. Paes ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Follicle Development ◽  
Antral Follicles ◽  
Positive Effects

scholarly journals The effects of FSH and activin A on follicle development in vitro

Reproduction ◽  
2012 ◽  
Vol 143 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Davina A Cossigny ◽  
Jock K Findlay ◽  
Ann E Drummond
Keyword(s):  
Combined Treatment ◽  
Primordial Follicle ◽  
Treated Group ◽  
Activin A ◽  
Pcr Analysis ◽  
Follicle Development ◽  
Development In Vitro ◽  
Rates Of Growth

Numerous studies have reported on the roles of activins in gonadal regulation; however, little is known about their specific roles in early folliculogenesis. Ovarian follicular growth was investigated in 10-day cultures of day 4 postnatal whole ovaries treated with activin A (ActA; 50 ng/ml), with or without FSH (100 ng/ml) in vitro. We hypothesized that treatment with ActA±FSH would affect rates of growth and atresia in follicles. None of the treatments affected primordial follicle activation, and antral follicles were not observed after 10 days in culture. Primordial follicle numbers from all treatment groups were ∼20% of those in day 4 fresh ovaries, indicating that activation had occurred. In the presence of ActA, preantral follicle numbers increased significantly (P<0.0001). ActA alone decreased the proportion of atretic follicles in the primary and preantral classes, whereas the combined treatment of ActA+FSH increased the proportion of atretic preantral oocytes. Real-time PCR analysis revealed that follistatin, FSH receptor, and activin βA and βB subunits were all expressed at significantly higher levels in the ActA-only treated group but not in the ActA+FSH group. Here, we report novel findings supporting the role of FSH in primordial follicle survival through an action on apoptosis and a stimulatory role of ActA in the primordial to primary and preantral stages of follicle development, suggesting an inhibitory action of activin on oocyte apoptosis.

121 ALGINATE-FIBRIN GEL MATRIX PROMOTES IN VITRO GROWTH OF DOG SECONDARY FOLLICLES

2012 ◽  
Vol 24 (1) ◽  
pp. 173 ◽  
Author(s):  
N. Songsasen ◽  
C. Guzy ◽  
D. E. Wildt
Keyword(s):  
Dynamic Mechanical Properties ◽  
Dimensional Structure ◽  
Follicle Development ◽  
Follicle Growth ◽  
Fibrin Gel ◽  
Chi Square ◽  
Paracrine Factors ◽  
Encapsulated Cells ◽  
Follicle Diameter

A previous study from our laboratory has demonstrated that preantral follicles from the dog that are cultured in alginate are able to grow and produce steroid hormones (Songsasen et al. 2011 Reproduction 142, 113–122). Here we investigated the influence of using a combination of alginate and a degradable biomaterial, fibrin, on dog follicle development in vitro. We hypothesised that the alginate and fibrin gel matrix would be superior to alginate alone because the former has dynamic mechanical properties that permit more expansive follicle development than the inert alginate-only system. Secondary follicles (128–220 μm in diameter) were collected from the ovaries of 4 prepubertal dogs (<6 months of age) and encapsulated in 0.5% alginate (n = 26) or 0.5% alginate + 12.5 mg mL–1 of fibrin (n = 22). Follicles were cultured for 12 days at 38.5°C in 100 μL of α-minimal essential medium + 2 mM of glutamine + 5.5 μg mL–1 of insulin + 5.5 μg mL–1 of transferrin + 6.7 ng mL–1 of selenium + 10 μg mL–1 of FSH and 1 ng mL–1 of LH + 3 mg mL–1 of polyvinyl alcohol. Follicle diameter was monitored and half of the medium exchanged every 48 h. Follicle survival was assessed based on ability to increase in size, as well as on oocyte and granulosa cell morphology. Comparisons of follicle growth rate for each culture day between the 2 treatments were conducted using Student's t-test and among culture days within the same group using ANOVA followed by a Holm-Sidak multiple comparison. Follicle survival was compared using a chi-square test. In both groups, follicles maintained the 3-dimensional structure and increased (P < 0.05) in size as culture period progressed. However, follicles encapsulated in alginate + fibrin grew larger (P < 0.05) than those in alginate alone. Specifically, follicles in alginate + fibrin were doubled in size by 12 days compared with a 60% increase for alginate alone. There were no differences (P > 0.05) in follicle survival between the 2 groups (27.0 and 38.1% for alginate and alginate-fibrin, respectively). Results demonstrate that a dynamic alginate-fibrin matrix enhances in vitro follicle growth. We suspect that the mechanism involved is related to facilitating expansion capacity. Specifically, it is likely that nondegradable alginate offers physical, but eventually restrictive, support to encapsulated cells. By contrast, in the gel combination, the fibrin degrades due to cell-secreted proteases that, in turn, permit more robust follicle expansion. Low follicle survival (<40%) in both treatments emphasises the need for more studies to identify influential endocrine/paracrine factors that enhance follicle growth and production of competent oocytes. Funded by NIH-KO1RR020564.

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