178 Evaluation of polar body extrusion following exposure of cattle oocytes to different concentrations of ethylene glycol cryoprotectant

2020 ◽  
Vol 32 (2) ◽  
pp. 217
Author(s):  
M. L. Mphaphathi ◽  
M. Nkadimeng ◽  
S. M. Sithole ◽  
M. D. Sebopela ◽  
F. V. Ramukhithi ◽  
...  

Cryoprotectant (CPA) toxicity has been recognised as a critical barrier to further advancement of cattle oocytes. Furthermore, CPA at high concentration might be toxic to oocytes, leading to osmotic shock and cell death (Arav et al. 1993). Selection of quality oocytes among a heterogeneous pool is mostly done subjectively. The use of Brilliant Cresyl Blue (BCB) stain for oocyte selection before ethylene glycol (EG) CPA toxicity test on cattle oocytes might be a useful tool. The objectives of this study were to elucidate the toxicity of EG penetrating CPA to cattle oocytes and the effectiveness of BCB on oocyte selection. Ovaries from cows of unknown reproductive status were collected from the local slaughterhouse and transported in warmed (37°C) saline water to the laboratory within 2h of slaughter. The oocytes (n=374) were exposed to 26mM BCB for 90min at 38.5°C under an atmosphere of 5% CO2. The other oocytes (n=450) were not exposed to BCB solution or CPA (positive control: no BCB and no CPA exposure). Oocytes were classified as BCB positive (+) with a varying degree of blue cytoplasm or BCB negative (−) with no blue cytoplasm. Oocytes were exposed in EG at different CPA concentrations as follows: Toxicity test 1 (TT1) was 0, 5, 10, and 15%, followed by exposure to TT2 as follows: 10, 20, and 30% (stepwise increased CPA). The oocytes were then invitro matured (IVM) as per treatment groups for 22h. After maturation, oocytes were removed from the maturation medium and denuded of granulosa cells by vortexing. The polar body extrusion was evaluated with the aid of Oosight Imaging System (Hamilton Thorne) connected to an inverted research microscope. Treatment means were compared using Fisher protected t-test least significant difference. There was a drastic decline of oocytes with polar body extrusion as CPA concentration increased (P<0.05): 40.5% (positive control, no BCB and no CPA exposure), 33.3% [(control, CPA exposure (EG 5 + 10%)], 23.1% [BCB− with CPA toxicity test (EG 5 + 10%)], 12.5% [(BCB− with CPA toxicity test (EG 10 + 20%)] and 4.9% [(BCB− with CPA toxicity test (EG 15 + 30%)]. The BCB+ groups (EG 5 + 10% and EG 10 + 20%) had significantly more oocytes with polar body extrusion (68.9% and 51.9%) compared with the positive control (40.5%), respectively (P<0.05). In conclusion, higher EG cryoprotectant concentrations compromise oocyte polar body extrusion following IVM. We recommend that BCB be used for selection of suitable oocytes before the CPA toxicity test because of its ability to stain larger and more competent oocytes from cattle.

2021 ◽  
Vol 33 (2) ◽  
pp. 176
Author(s):  
S. M. Sithole ◽  
M. L. Mphaphathi ◽  
M. D. Sebopela ◽  
T. L. Nedambale

The invitro embryo production technique is one of the assisted reproduction technologies that has the potential in speeding up genetic improvement in cattle. The developmental competence of invitro-matured oocytes is influenced by several factors during invitro maturation (IVM), such as maturation environment, oocyte quality, type of media, and additives. The objective of the present study was to compare two IVM media (TCM-199 and BO-IVM) on cattle oocyte maturation rate invitro. Cattle ovaries were collected from local slaughterhouse and transported to the laboratory in a thermos flask containing 0.9% saline (Adcock Ingram Critical care) at 37°C. Oocytes were retrieved from the ovaries by the aspiration technique, and then matured invitro in 500µL of TCM-199 (supplemented with 10% fetal bovine serum, FSH, LH, and E2) or in 500µL of commercially available BO- IVM (Bioscience) medium, both covered with mineral oil for 22h at 38.5°C with 5% CO2 and 5% O2. After 22h of IVM, oocyte polar body extrusion was evaluated with the aid of Oosight Imaging System (Hamilton Thorne) connected to an inverted microscope. The total number of oocytes matured in TCM-199 and BO-IVM media were 401 and 396, respectively. The experiment was replicated 19 times. Data were analysed using the GenStat® program (VSN International). Means of different treatments were separated using Fisher’s protected t-test least significant difference at 5% level of significance. No difference was recorded for polar body extrusion rates in TCM-199 (50.6±13.9) and BO-IVM (47.3±13.7) media. In conclusion, TCM-199 and BO-IVM media did not differ in terms of maturation rate; thus, both can be used for successful cattle oocyte IVM.


2014 ◽  
Vol 129 (S1) ◽  
pp. S45-S50 ◽  
Author(s):  
J H Kim ◽  
J Rimmer ◽  
N Mrad ◽  
S Ahmadzada ◽  
R J Harvey

AbstractObjective:This study investigated the effect of Betadine on ciliated human respiratory epithelial cells.Methods:Epithelial cells from human sinonasal mucosa were cultured at the air–liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system.Results:Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings.Conclusion:Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.


2004 ◽  
Vol 16 (2) ◽  
pp. 268 ◽  
Author(s):  
S.E. Beaumont ◽  
D.K. Berg ◽  
G.W. Asher

Successful activation of red deer oocytes is a necessary prerequisite for the cloning of red deer individuals with desirable genetic characteristics. To investigate this, an established biphasic protocol used for oocyte activation in sheep was investigated for suitability. The method chosen was 5μM Ionomycin for 5min followed by 2mM 6DMAP for 3h ( Loi P et al., 1998 Biol. Reprod. 58, 1177–1187). The medium used during activation and subsequent culture was Deer Synthetic Oviduct Fluid, which has been shown to support routine in vitro fertilization and blastocyst development (15%) of in vitro-matured red deer oocytes (DSOF, Berg D et al., 2003 Theriogenology 59, 189–205). Red deer abattoir-derived COCs were matured in vitro for 22h before random allocation across 3 treatment groups comprising a standard IVF group, the activation group and a negative control group exposed to medium only. Activation treatment oocytes were stripped of cumulus by vortexing in 0.1% hyaluronidase before selecting for first polar body extrusion. First-step activation was performed in medium comprising HEPES-buffered IVF-DSOF containing 4mM Ca2+. Second-step activation used 3mM Ca2+ early DSOF under 7% O2, 5% CO2, and 88% N2 at 38.5°C. Standard IVF was conducted at 23h post-IVM using 4mM Ca2+ IVF-DSOF and 0.5×106mL−1 final sperm concentration. Following activation and IVF, oocytes were washed 3 times in HEPES DSOF before culture for 7 days in sequential DSOF with late DSOF on Day 4 containing 1.5mM Ca2+. Cleavage was assessed 24h after activation, and all blastocysts were fixed for cell counts. Four replicates of each treatment were performed. Cleavage and blastocyst rates were examined by chi-square analysis and cell numbers by ANOVA. First polar body extrusion rate was 84%. Cleavage was similar between the activation treatment and IVF (P&gt;0.05 ); but a significant difference was found in blastocyst development rates (P&lt;0.05) with the Ionomycin and 6DMAP protocol being superior to the IVF treatment. Exposure to high Ca2+ media alone resulted in only 5% of the negative control oocytes cleaving to 2 cells. Results show that Ionomycin and 6DMAP are effective in activating red deer oocytes and DSOF is a suitable medium to produce parthenogenetic blastocysts.


2021 ◽  
Vol 33 (2) ◽  
pp. 174
Author(s):  
K. M. Honneysett ◽  
M. L. Mphaphathi ◽  
A. M. Maqhashu ◽  
E. C. Webb

Oocyte recovery is a reproductive technology that can be done by using two techniques, aspiration and slicing. Invitro maturation (IVM) is an additional reproductive technology used to advance an oocyte to a maturation stage; thereafter, it may be used during IVF. The objectives of the present study were (1) to compare two different oocyte retrieval methods (aspiration and slicing) from pig ovaries on oocyte quality and quantity, and (2) to compare three different IVM media [NCSU 37, TCM-199, and modified porcine follicular fluid (mpFF=porcine follicular fluid+FSH+LH] on oocytes’ polar body extrusion. During aspiration, an 18G needle was attached to a 10-mL syringe and all visible follicles were aspirated. During slicing, a surgical blade was used to slice the ovaries held in mDPBS. Follicular fluid collected from both methods was assessed for the presence of oocytes with the aid of a microscope. The collected oocytes were then categorized as Grade A, B, or C: Grade A=oocytes with compacted, multilayered cumulus cells and a homogeneous ooplasm; Grade B=oocytes with a compact cumulus cell layer with homogeneous ooplasm; Grade C=oocytes with a less compact cumulus cell layer with irregular ooplasm containing dark granules. The IVM media were placed in a four-well multidish; thereafter Grades A and B oocytes were allocated per treatment groups and matured for 44h. The treatment means were compared using the Fisher’s protected t-test least significant difference. The results showed significant differences between the grades of oocytes (P&lt;0.05) with Grade A and B oocytes accounting for 50.8% of total oocytes (193.8) for aspiration and 58.7% of total oocytes (488.6) for slicing. The oocytes polar body extrusion was recorded as 25.3, 84.2, and 73.8% for NCSU 37 (P&lt;0.05) and TCM-199 and mpFF respectively (P&gt;0.05). In conclusion, the slicing method proved to be better than aspiration with regards to the retrieval of Grades A and B oocytes as well as the total number of oocytes retrieved. The TCM-199 and mpFF media had a higher percentage of oocytes with polar body extrusion than NCSU 37.


2021 ◽  
Vol 33 (2) ◽  
pp. 173
Author(s):  
M. L. Mphaphathi ◽  
K. M. Honneysett ◽  
T. T. Maduwa ◽  
K. G. Pohler ◽  
T. L. Nedambale

The invitro maturation (IVM) rate of pig oocytes is a critical step for subsequent invitro embryo production. The objective of the present study was to compare different IVM media (NCSU 23, NCSU 37, TCM-199, pFF, BO-IVM commercial, and Bovine IVM) on polar body extrusion in pig oocytes following 44h of maturation duration. Ovaries from sows were collected from the local slaughterhouse and transported in warmed (38°C) saline to the laboratory, within 2h following slaughter. The slicing method was used to retrieve oocytes from the ovaries. Collected oocytes (n=353) were selected and washed three times in TCM-199+10% fetal bovine serum. The oocytes were then subjected to IVM as per treatment groups for 44h. Following maturation period, oocytes were removed from each maturation medium and denuded of granulosa cells by vortexing. The oocytes polar body extrusion was evaluated with the aid of OosightTM Imaging Sytem connected to an inverted research microscope. Treatment means were compared using Fisher’s protected least significant difference t-test. Polar body extrusion was 30.0, 18.5, 32.8, 22.1, 32.1, and 27.0% for BO IVM commercial, Bovine IVM, NCSU 23, NCSU 37, TCM-199, and pFF media, respectively (P&gt;0.05). The NCSU 23 and TCM-199 had numerically higher percentages of oocytes with extruded polar body compared with other treatments groups (P&gt;0.05). The lowest (18.5%) polar body extrusion was recorded in Bovine IVM medium. In conclusion, all the IVM media tested can be used during IVM of pig oocytes, with NCSU 23 and TCM-199 having numerically higher polar body extrusion percentages.


Author(s):  
H Hajarian ◽  
H Wahid ◽  
Y Rosnina ◽  
M Daliri ◽  
M Dashtizad ◽  
...  

The effectiveness of different cryodevices (open-pulled straw (OPS), electron microscopy grid (EMG), and Cryotop was evaluated for vitrification of immature bovine oocytes. Polar body, metaphase II stage (MII), survivability, and subsequent developmental rates were determined. Only oocytes with four or five layers of cumulus cells were used. Oocytes were equilibrated in two vitrification solutions - 1: 10% DMSO + 10% ethylene glycol (EG) for 30-45sec and 2: 20% DMSO + 20% EG +0.5M sucrose for 25sec -, mounted on one of the cryodevices and directly plunged into liquid nitrogen for 10 days. Immature vitrified oocytes using Cryotop showed the highest rates of polar body extrusion (PB) and nuclear maturity (MII); 41 and 58% respectively. Vitrified oocytes using OPS and EMG showed 26 and 32%; and 35 and 46% of PB and MII rates, respectively. The highest survivability resulted from Cryotop and EMG groups and no significant difference was found between them. Vitrified oocytes using Cryotop had the highest cleavage and blastocyst rates. All of the mean rates for vitrified immature oocytes were significantly lower than that of control group (P<0.05). The results of this study showed the superiority of Cryotop device for vitrification of immature bovine oocytes


2021 ◽  
Vol 33 (2) ◽  
pp. 177
Author(s):  
M. D. Sebopela ◽  
M. L. Mphaphathi ◽  
S. M. Sithole ◽  
T. L. Nedambale

Climate change represents a major stressful environmental condition that compromises the reproductive efficiency of animals. The temperature affects various components of the maturation processes in cattle oocytes, this includes disruptions of oocyte development and maturation. Therefore, the study aimed to compare the effects of different incubation temperatures (32.5, 33.5 34.5, 35.5, 36.5, 37.5, 38.5, 39.5, 40.5, 41.5, 42.5, and 43.5°C) on the maturation rate of cattle oocytes. Cattle ovaries were collected from a local abattoir and transported to the laboratory in thermo flask at 37°C. Oocytes were recovered from ovaries using the aspiration method and matured using 500 uL of TCM-199 medium supplemented with 10% fetal bovine serum, FSH, LH, and E2 covered with mineral oil. The maturation rate of oocytes was determined by the extrusion of the first polar body after 22h of IVM period. The total number of 80 oocytes were matured in each group and replicated 4 times. Data were analysed using GenStat® statistical program (VSN International). Comparisons were considered significantly different (P&lt;0.05) using Fisher’s protected least significant difference test. The oocyte polar body extrusion at 32.5 (0±0), 33.5 (4.5±5.2), 34.5 (22.0±1.4), 35.5 (29.5±7.6), 36.5 (41.5±3.1), 37.5 (55.5±4.1), 38.5 (62.2±3.3), 39.5 (49.5±3.3), 40.5 (17.3±6.4), 41.5 (10.3±5.7), 42.5 (8.2±5.9), and 43.5°C (5.7±7.8) (P&lt;0.05) was recorded. The highest percentages of oocytes with polar body extrusion were at 37.5°C (55.5±4.1) and 38.5°C (62.2±3.3) and differed significantly from all other treatment groups (P&lt;0.05). Temperature lower than 37.5°C and higher than 39.5°C did not intensify oocyte polar body extrusion. We concluded that the temperatures of 37.5°C and 38.5°C were suitable for IVM of cattle oocytes with acceptable polar body extrusion rates compared with other temperatures.


2021 ◽  
Vol 33 (2) ◽  
pp. 122
Author(s):  
T. Somfai ◽  
N. T. Hiep ◽  
K. Kikuchi ◽  
Y. Hirao

Oocyte vitrification is an important approach for invitro gene banking of female germplasm; however, in pigs, it hampers embryo development. In cattle, vitrification at the MII stage was reported to alter epigenetic status in oocytes and even in subsequently developing embryos (Chen et al. 2016 Theriogenology 86, 868-878). The present study investigated the effect of vitrification at the immature stage of porcine oocytes on DNA methylation status and its relevance to subsequent embryo development. Immature cumulus–oocyte complexes were vitrified in microdrops and warmed (vitrified group) or treated with cryoprotectant agents (17.5% ethylene glycol + 17.5% propylene glycol, CPA group) by our method (Appeltant et al. 2018 Cryobiology 85, 87-94). Then they were subjected to IVM, parthenogenetic activation (PA), and embryo culture. From each batch, a group of oocytes was processed without treatment (control group). Oocyte survival and polar body extrusion were recorded after IVM. Cleavage and blastocyst developmental rates were recorded on Day 2 and 6 of culture, respectively (Day 0=PA). In each replication, DNA methylation was assayed in representative oocytes at the MII stage after IVM and in embryos at the 2- to 4-cell stage on Day 2 by immunostaining with 5-methylcytosine (5mC). Relative fluorescent intensity of 5mC in the chromatin was compared among groups. The experiment was replicated 3 times. Data were analysed by ANOVA. After IVM, there was no significant difference among the control, CPA, and vitrified groups in terms of the percentage of live oocytes (99.3, 96.4, and 94.0%, respectively) or polar body extrusion (88.6, 86.9, and 79.6%, respectively). After PA of oocytes with a polar body, there was no difference between the control and CPA groups in the percentage of cleavage (84.1 and 80.7%, respectively) or blastocyst development of cleaved embryos (63.3 and 79.3%, respectively). However, in the vitrified group, cleavage and blastocyst development rates (46.6 and 33.5%, respectively) were reduced (P&lt;0.05) compared with the other groups. The 5mC fluorescence in the DNA of oocytes at the MII stage in the CPA and vitrified groups were similar and significantly lower than that in the control group (0.88±0.02, 0.87±0.001, and 1.0±0.02, respectively) but higher than that in the negative control processed without primary antibody (0.33±0.02). In the embryos at the 2- to 4-cell stage, 5mC fluorescence was not significantly different among the control, CPA, and vitrified groups (1.0±0.1, 0.99±0.1, and 0.96±0.1, respectively) but was significantly higher than that of the negative control (0.36±0.04). In conclusion, CPA treatment reduced DNA methylation levels in oocytes. However, it was restored during early embryo development and did not affect blastocyst development. The results suggest that reduced DNA methylation in vitrified oocytes is caused by CPA but it may not be responsible for their reduced ability to develop to blastocysts.


2020 ◽  
Vol 32 (2) ◽  
pp. 139
Author(s):  
T. Somfai ◽  
H. T. Nguyen ◽  
M. T. Nguyen ◽  
T. Q. Dang-Nguyen ◽  
H. Kaneko ◽  
...  

Porcine immature oocytes can survive vitrification at high rates and retain their ability to undergo maturation and fertilization; however, the procedure reduces their competence for subsequent embryo development via unknown mechanisms (Somfai et al. 2014 Plos One 9, e97731). The aim of the present study was to clarify whether our vitrification procedure at the germinal vesicle stage triggers apoptosis in oocytes and subsequent developing embryos. Immature porcine cumulus-oocyte complexes obtained from slaughterhouse-derived ovaries were vitrified and warmed by our method (Appeltant et al. 2018 Cryobiology 85, 87-94) immediately after collection (vitrified group). The oocytes were equilibrated in 2% (vol/vol) ethylene glycol and 2% (vol/vol) propylene glycol for 13-15min. Then, they were vitrified by dropping them into liquid nitrogen in 2-μL microdrops of a medium composed of 17.5% ethylene glycol, 17.5% propylene glycol, 0.3M sucrose, and 50mgmL−1 polyvinylpyrrolidone. After warming, they were subjected to IVM, fertilization (IVF), and embryo culture using chemically defined media (Yoshioka et al. 2008 J. Reprod. Dev. 54, 208-213). From each collected batch, a group of oocytes was processed without vitrification (control group). Apoptosis was assayed in membrane-intact oocytes at the end of IVM and in cleavage-stage embryos on Day 2 after IVF (Day 0) by the CaspACE FITC-VAD-FMK In Situ Caspase Marker (Promega; Experiment 1), deoxynucleotidyl transferase (TdT) dUTP nick-end labelling (TUNEL; Experiment 2), and analysis of mRNA levels by RT-qPCR for the pro-apoptotic Bax and CASP3 genes (Experiment 3). Each experiment was replicated three times. Data were analysed by Kruskal-Wallis test followed by Dunn's multiple comparisons test. The mean survival rate of vitrified oocytes was 89.2%. There was no significant difference between the control and vitrified groups in relative caspase levels in IVM oocytes and in 2- to 4-cell embryos after IVF; however, significantly increased caspase activity (P&lt;0.05) was detected in oocytes and embryos after treatment with 10 μM staurosporine (positive control). There was no significant difference between the control and vitrified groups in the proportion of TUNEL-positive oocytes (4.1 and 0.8%, respectively) and embryos (0 and 0%, respectively), whereas 96.6% of oocytes and 100% of cleavage stage embryos treated with 1000IUmL−1 deoxyribonuclease I (positive control) were proven to be TUNEL positive (P&lt;0.05). Similar mRNA levels for Bax and CASP3 genes were detected in oocytes at the end of IVM and subsequent developing 4- to 8-cell embryos between the control and vitrified groups. In conclusion, vitrification of porcine oocytes at the germinal vesicle stage by our method did not trigger apoptosis in oocytes and subsequent developing embryos. This work was supported by the Japan Science and Technology Agency (JST)/Japan International Cooperation Agency (JICA) Science and Technology Research Partnership for Sustainable Development (SATREPS).


1987 ◽  
Vol 18 (3) ◽  
pp. 250-266 ◽  
Author(s):  
R. Jane Lieberman ◽  
Ann Marie C. Heffron ◽  
Stephanie J. West ◽  
Edward C. Hutchinson ◽  
Thomas W. Swem

Four recently developed adolescent language tests, the Fullerton Test for Adolescents (FLTA), the Test of Adolescent Language (TOAL), the Clinical Evaluation of Language Functions (CELF), and the Screening Test of Adolescent Language (STAL), were compared to determine: (a) whether they measured the same language skills (content) in the same way (procedures); and (b) whether students performed similarly on each of the tests. First, respective manuals were reviewed to compare selection of subtest content areas and subtest procedures. Then, each of the tests was administered according to standardized procedures to 30 unselected sixth-grade students. Despite apparent differences in test content and procedures, there was no significant difference in students' performance on three of the four tests, and correlations among test performance were moderate to high. A comparison of the pass/fail rates for overall performance on the tests, however, revealed a significant discrepancy between the proportions of students identified in need of further evaluation on the STAL (20%) and the proportion diagnosed as language impaired on the three diagnostic tests (60-73%). Clinical implications are discussed.


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