Name: proteolytically degraded alginate hydrogels and hydrophobic microbioreactors for porcine oocyte encapsulation
Uploaded: 2020-07-30T13:00:00
Description: Watch this Scientific Journal Video about Proteolytically Degraded Alginate Hydrogels and Hydrophobic Microbioreactors for Porcine Oocyte Encapsulation at JoVE.com

The authors are very grateful to: dr Waclaw Tworzydlo (Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Jagiellonian University) for technical facilities in TEM; to Ms. Beata Snakowska (Department of Endocrinology, Institute of Zoology and Biomedical Research, Jagiellonian University) for technical assistance; to the Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, JEOL JEM 2100HT (JEOL, Tokyo, Japan). This work was supported by grant 2018/29/N/NZ9/00983 from National Science Centre Poland.

The following procedures were approved by the Animal Welfare Committee at the Institute of Zoology and Biomedical Research at Jagiellonian University.
1. Isolation of porcine cumulus-oocyte complexes
<ol>
	<li>To collect material for the isolation of ovarian follicles, excise porcine ovaries from prepubertal gilts (approximately 6-7 months of age, weighing 70 to 80 kg) at a local slaughterhouse. Choose approximately 20 pig ovaries from 10 animals for COCs isolation in each experiment. 
...

The ability to maintain in vitro growth not only of the oocyte but also of cumulus cells surrounding it and simultaneously supporting its maturation is exceedingly essential for the successful assisted reproductive technologies and for furthering the understanding of somatic cell/oocyte interactions especially in species undergoing prolonged follicular growth such as human beings or pigs. Continuously improved IVM techniques are becoming useful tool to preserve reproductive options in cases of polycystic ovarian syndrome...

The development of various culture systems, including three-dimensional (3D) ones, aims to provide optimal conditions for the growth and maturation of oocytes isolated from the follicles even at earliest stages of development. This is of great importance for assisted reproductive techniques (ART), especially in view of the increasing number of women who are struggling with infertility after cancer treatment1. Maturation of oocytes in in vitro conditions (IVM) is already a well-established technique mainly used for in vitro embryo generation for the purpose of livestock reproduction2. However, in most mammalian species, even if high rates of maturation of cumulus-oocyte complexes (COCs) can be achieved (range 60 to 90&#160;%)3, their developmental competence is still inadequate to the needs. This is because the development of the zygotes obtained in such a way even up to the blastocyst stage is low and after the transfer into surrogate animals their viability to term is reduced. Consequently, there is a need to increase the developmental competence of embryos obtained from oocytes that were subjected to the IVM procedure4. Therefore, new maturation media5 are being devised and various periods of in vitro culture are tested6,7 along with supplementation of culture media with various growth factors and molecules8,9.
The first step of any complete IVM system is to create optimal conditions for sustainable growth of oocytes during in vitro culture. The oocyte growth is one of the specific indicators of the oocyte&#39;s ability to resume meiosis10,11. In addition, an appropriate oocyte in vitro culture system must be capable of supporting its nuclear maturation and cytoplasmic differentiation12. The morphology of the cumulus-oocyte complex is another important indicator used in ART clinics to select the best oocyte for subsequent steps of in vitro fertilization (IVF) procedure in humans and livestock12,13. Among morphological characteristics of COCs considered are: the oocyte diameter, its cytoplasm granulation and the first polar body integrity14,15. Besides, the oocyte developmental potential is correlated to the appearance and compaction of cumulus cells and number of their layers surrounding the oocyte. Very important for the appropriate oocyte in vitro culture system is also the maintenance of oocyte&#8211;cumulus cells proper interactions and cytoskeleton stability16,17,18,19. So far, in vitro oocyte growth within human COCs has been demonstrated20. The use of cow COCs also resulted with live births. These were isolated from immature ovarian follicles and then cultured for 14 days until the oocyte was sufficiently large to undergo the IVF procedure21. Similarly, COCs isolated from baboon antral follicles, subjected to IVM after in vitro culture yielded oocytes capable of reinitiating meiosis to the metaphase II stage with a normal appearing spindle structure22. However, in this study the authors did not try to fertilize them. Nevertheless such results indicate that a similar procedure could be applied not only to these particular mammalian species but also to human cumulus-oocyte complexes obtained from follicles what should allow to obtain oocytes of good quality suitable for a successful IVF technique.
The above described results were obtained with the application of conventional IVM protocols during which oocytes were cultured in two-dimensional (2D) systems. The routine procedure in 2D culture systems is covering oocytes, immersed in a drop of an appropriate culture media, with mineral oil23,24. It is assumed that an oil overlay during in vitro oocyte culture serves to prevent liquid evaporation, thus ensuring the maintenance of proper pH and osmotic pressure in the culture. Although such a 2D culture system allows to obtain, even up to 87% of mature pig oocytes25, it has been proven that the mineral oil overlay causes substantial diffusion of lipid soluble materials which are necessary for proper oocytes development26. Additionally, because of steroids (progesterone and estrogens) diffusion into the mineral oil during oocyte culture, a delay of nuclear maturation and reduction in developmental competence achievement of pig oocytes was observed. This may result in obtaining a small number of zygotes, which additionally are characterized by low developmental capacity to the stage of the blastocyst and by poor viability after transfer into recipient animals27. Therefore, attempts are being made to increase the developmental competence of embryos derived from oocytes received after IVM procedure, by creating optimal conditions for achieving both cytoplasmic and nuclear maturity of oocytes cultured together with CCs as complexes, especially using three-dimensional (3D) systems. Various innovative 3D in vitro culture systems have been developed in the last two decades28,29. These were designed to maintain the natural spatial organization of cells and to avoid their flattening in culture dishes what cannot be achieved in the traditional 2D cultures. The structural and functional activity of cultured COCs can be ensured by the maintenance of their proper architecture and undisturbed communication through gap-junctions between various compartments30. The suitability of bio-scaffolds for 3D in vitro culture of cumulus&#8211;oocyte complexes has been evaluated using natural biomaterials such as various components of the extra-cellular matrix (ECM; collagen and hyaluronic acid)31 or inert polymers (alginate)32. These attempts tested in several species brought promising results in terms of oocyte meiosis resumption and achievement of their full competence33,34,35. However so far, no 3D system suitable for COCs maturation isolated from large domestic animals, including pigs, has been developed.
This work describes two protocols that can be used for the 3D culture of porcine COCs. The first protocol describes encapsulation in fibrin-alginate beads (FAB). FAB can be formed by simultaneous mixing an alginate and fibrin solution, which undergo a synchronous gelation process. This combination provides a dynamic mechanical environment because both components contribute to matrix rigidity. A similar solution has been used previously for mouse ovarian follicle culture and maturation36. In the case of the presented protocol, to avoid premature degradation of the alginate-fibrin network, appropriately higher concentrations of calcium chloride solution are used, ensuring a fast and stable gelation process. The dynamic mechanical environment creates conditions similar to these in the natural intra-follicular environment in which COCs reside and increase in size. Additionally, the work shows representative results of COCs 3D culture systems, in which these are suspended in a drop of medium and encapsulated with fluorinated ethylene propylene (FEP; a copolymer of hexafluoropropylene and tetrafluoroethylene) powder particles, to form microbioreactors (Liquid Marbles, LM). LM are a form of 3D bioreactor that have been previously shown to support, among others, growth of living microorganisms37, tumor spheroids38 and embryonic stem cells39. LMs have been also successfully used for sheep oocyte culture40. In most experiments using LMs, bioreactors were prepared using polytetrafluoroethylene (PTFE) powder bed with particle size of 1 &#956;m41. The presented protocol uses FEP, which is very similar in composition and properties to the fluoropolymers PTFE. But FEP is more easily formable and softer than PTFE and what is especially important, it is highly transparent.
Both 3D systems maintain the gaseous in vitro culture environment. They also maintain COCs 3D organization by preventing their flattening and consequent disruption of gap junctions, preserving their functional relationship between the oocyte and surrounding follicular cells.

<table border="0" cellpadding="0" cellspacing="0" style="width:761px;" width="761">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">General</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td style="width:204px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:256px;">Antibiotic Antimycotic (100x) 100ml</td>
			<td style="width:139px;">Thermo Fisher</td>
			<td>15240062</td>
			<td style="width:204px;">2.5% final concentration for Handling Medium. 1% in PBS (step 1.2)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">DMEM/F12 (500ml)</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td>D8062</td>
			<td style="width:204px;">Handling and Maturation Medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">DPBS (w/o Ca, Mg), 1x, 500ml</td>
			<td style="width:139px;">Thermo Fisher</td>
			<td>14190144</td>
			<td style="width:204px;"></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:256px;">FCS (100 ml)</td>
			<td style="width:139px;">Thermo Fisher</td>
			<td>16140063</td>
			<td style="width:204px;">10% final concentration for both Handling Medium and Maturation Medium. (steps: 1.5. 2.6.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">PBS (1x, pH 7.4) 500ml</td>
			<td style="width:139px;">Thermo Fisher</td>
			<td>10010023</td>
			<td style="width:204px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">TBS Stock Solution (10x, pH 7.4) 500 ml</td>
			<td>Cayman Chemicals</td>
			<td>600232</td>
			<td style="width:204px;">1x final concentration. Other brand can be use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Maturation Medium</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">hCG (1 VIAL of 10 000 U)</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">CG10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">PMSG</td>
			<td style="width:139px;">BioVendor</td>
			<td>RP1782721000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Fibrin-alginate beads</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Alginate Lyase</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">A1603</td>
			<td>(Step 2.11.1)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Thrombin</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td>T9326-150UN</td>
			<td>(Step 2.1)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Calcium Chloride</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">C5670</td>
			<td>(Step 2.1)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Fibrinogen (250mg)</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">F3879</td>
			<td>(Step 2.2)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">Sodium Alginate</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td>W201502</td>
			<td style="width:204px;">(Step 2.3) use for alginate solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Liquid Marble</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">FEP</td>
			<td style="width:139px;">Dyneon GmbH 3M AdMD</td>
			<td style="width:162px;">A-66670</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Morphological examination</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:104px;width:256px;">LIVE/DEAD Viability/Cytotoxicity Kit, for mammalian cells</td>
			<td style="width:139px;">Thermo Fisher</td>
			<td>L3224</td>
			<td style="width:204px;">(Step 4.1.) Emitted fluorescence: 494 nm for calcein, 528 nm for EthD-1; measure: 517 nm for calcein, 617 nm - EthD-1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">VECTASHIELD Antifade Mounting Medium</td>
			<td style="width:139px;">Vector Laboratories</td>
			<td>H-1000</td>
			<td>mounting medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Ultrastructure examination</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">Glutaraldehyde solution</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">G5882</td>
			<td style="width:204px;">2.5% final concentraion (Step 4.2.1.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">LR White resin</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">L9774</td>
			<td>(Step 4.2.4.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Methylene blue</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">M9140</td>
			<td>(Step 4.2.5.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Osmium Tetroxide</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">O5500</td>
			<td>(Step 4.2.3.)</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">Sodium cacodylate trihydrate</td>
			<td style="width:139px;">Sigma-Aldrich</td>
			<td style="width:162px;">C0250</td>
			<td style="width:204px;">Use for preparing 0.1M sodium cacodylate buffer (pH 7.2)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Uranyl Acetate</td>
			<td style="width:139px;">POCH</td>
			<td>868540111</td>
			<td>(Step 4.2.4.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Specific instruments, tools</td>
			<td style="width:139px;"></td>
			<td style="width:162px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">30 mm Pteri dish</td>
			<td style="width:139px;">TPP</td>
			<td>93040</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">60 mm IVF Petri dish</td>
			<td style="width:139px;">Falcon</td>
			<td>353653</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">Ez-Grid Premium Cell Handling Pipettor</td>
			<td style="width:139px;">RI Life Sciences</td>
			<td style="width:162px;">8-72-288</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Ez-Tip</td>
			<td style="width:139px;">RI Life Sciences</td>
			<td style="width:162px;">8-72-4155/20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Heating Table</td>
			<td style="width:139px;">SEMIC</td>
			<td style="width:162px;"></td>
			<td>Other brands can be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Incubator</td>
			<td style="width:139px;">Panasonic</td>
			<td style="width:162px;">MCO-170AIC-PE</td>
			<td>Other brands can be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Sterile petri dish (10 cm)</td>
			<td>NEST Biotechnology</td>
			<td>704002</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:256px;">Sterile syringe filters with 0.2 &#181;m</td>
			<td style="width:139px;">GOOGLAB SCIENTIFIC</td>
			<td>GB-30-022PES</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:256px;">Thermos</td>
			<td style="width:139px;">Quechua</td>
			<td>5602589</td>
			<td>Other brands can be used</td>
		</tr>
	</tbody>
</table>

proteolytically degraded alginate hydrogels and hydrophobic microbioreactors for porcine oocyte encapsulation

In reproductive biology, the biotechnology revolution that began with artificial insemination and embryo transfer technology led to the development of assisted reproduction techniques such as oocyte in vitro maturation (IVM), in vitro fertilization (IVF) and cloning of domestic animals by nuclear transfer from somatic cell. IVM is the method particularly of significance. It is the platform technology for the supply of mature, good quality oocytes for applications such as reduction of the generation interval in commercially important or endangered species, research concerning in vitro human reproduction, and production of transgenic animals for cell therapies. The term oocyte quality includes its competence to complete maturation, be fertilized, thereby resulting in healthy offspring. This means that oocytes of good quality are paramount for successful fertilization including IVF procedures. This poses many difficulties to develop a reliable culture method that would support growth not only of human oocytes but also of other large mammalian species. The first step in IVM is the in vitro culture of oocytes. This work describes two protocols for the 3D culture of porcine oocytes. In the first, 3D model cumulus-oocyte complexes (COCs) are encapsulated in a fibrin-alginate bead interpenetrating network, in which a mixture of fibrin and alginate are gelled simultaneously. In the second one, COCs are suspended in a drop of medium and encapsulated with fluorinated ethylene propylene (FEP; a copolymer of hexafluoropropylene and tetrafluoroethylene) powder particles to form microbioreactors defined as Liquid Marbles (LM). Both 3D systems maintain the gaseous in vitro culture environment. They also maintain COCs 3D organization by preventing their flattening and consequent disruption of gap junctions, thereby preserving the functional relationship between the oocyte, and surrounding follicular cells.

In COCs using both IVM systems, the granulosa cells adhered tightly to each other, and most of the recovered COCs had intact layers of cumulus cells (Figure 1A,B). Additionally, substantial proportion of cumulus cells were retained.
The results obtained from the COCs viability analysis confirmed that both systems applied for the encapsulation of porcine oocytes in 3D in vitro conditions ensured optimal growth conditions (Figur...

Watch this Scientific Journal Video about Proteolytically Degraded Alginate Hydrogels and Hydrophobic Microbioreactors for Porcine Oocyte Encapsulation at JoVE.com

Proteolytically Degraded Alginate Hydrogels and Hydrophobic Microbioreactors for Porcine Oocyte Encapsulation

Presented here are two protocols for the encapsulation of porcine oocytes in 3D culture conditions. In the first, cumulus-oocyte complexes (COCs) are encapsulated in fibrin-alginate beads. In the second, they are enclosed with fluorinated ethylene propylene powder particles (microbioreactors). Both systems ensure optimal conditions to maintain their 3D organization.

In reproductive biology, the biotechnology revolution that began with artificial insemination and embryo transfer technology led to the development of ...

Research

JoVE Journal

Biology

Title Cell Encapsulation by Droplets

Primer Extension Capture: Targeted Sequence Retrieval from Heavily Degraded DNA Sources

We present a method of targeted DNA sequence retrieval from DNA sources which are heavily degraded and contaminated with microbial DNA, as is typical of ...

Cellular Encapsulation in 3D Hydrogels for Tissue Engineering 

The 3D encapsulation of cells within hydrogels represents an increasingly important and popular technique for culturing cells and towards the development ...

PuraMatrix Encapsulation of Cancer Cells

Increasing evidence suggests that culturing cancer cells in three dimensions more accurately recapitulates the complexity of tumor biology. Many of these ...

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment

Mistakes in chromosome segregation lead to aneuploid cells.  In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to ...

Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification

In contrast to other chromatographic methods for purifying proteins (e.g. gel filtration, affinity, and ion exchange), hydrophobic interaction ...

Single Oocyte Bisulfite Mutagenesis

Epigenetics encompasses all heritable and reversible modifications to chromatin that alter gene accessibility, and thus are the primary mechanisms for ...

Preparation of DNA-crosslinked Polyacrylamide Hydrogels

Mechanobiology is an emerging scientific area that addresses the critical role of physical cues in directing cell morphology and function. For example, ...

FRET Imaging in Three-dimensional Hydrogels

Imaging of F&#246;rster resonance energy transfer (FRET)&#160;is a powerful tool for examining cell biology in real-time. Studies utilizing FRET commonly ...

Fabrication of Amyloid-&#946;-Secreting Alginate Microbeads for Use in Modelling Alzheimer's Disease

Fabrication of Amyloid-ÃƒÅ½Ã‚Â²-Secreting Alginate Microbeads for Use in Modelling Alzheimer's Disease

According to the amyloid cascade hypothesis, the earliest trigger in the development of Alzheimer&#8217;s disease (AD) is the accumulation of toxic ...