Hypothermia and Mammalian Gametes

Parks, John E.

doi:10.1016/b978-012399770-8/50006-x

Cited by 36 publications

(29 citation statements)

References 93 publications

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“…Determination of optimal extender composition for various species has enabled development of better cryopreservation protocols [14,38,53]. An ideal sperm extender should have optimum pH, buffering capacity, suitable osmotic pressure and protect sperm against cold shock [45].…”

Section: Introductionmentioning

confidence: 99%

The effects of cooling rates and type of freezing extenders on cryosurvival of rat sperm

2013

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Cryopreservation of rat sperm is very challenging due to its sensitivity to various stress factors. The objective of this study was to determine the optimal cooling rate and extender for epididymal sperm of outbred Sprague Dawley (SD) and inbred Fischer 344 (F344) rat strains. The epididymal sperm from 10–12 weeks old sexually mature SD and F344 strains were suspended in five different freezing extenders, namely HEPES buffered Tyrode’s lactate (TL-HEPES), modified Kreb’s Ringer bicarbonate (mKRB), 3% dehydrated skim milk (SM), Salamon’s Tris-citrate (TRIS), and tes/tris (TES). All extenders contained 20% egg yolk, 0.75% Equex Paste and 0.1 M raffinose or 0.1 M sucrose. The sperm samples in each extender were cooled to 4°C and held for 45 min for equilibration before freezing. The equilibrated sperm samples in each extender were placed onto a shallow quartz dish inserted into Linkam Cryostage (BCS 196). The samples were then cooled to a final temperature of −150 °C by using various cooling rates (10, 40, 70, and 100 °C/min). For thawing, the quartz dish containing the sperm samples were rapidly removed from the Linkam cryo-stage and placed on a 37 °C slide warmer and held for 1 min before motility analysis. Sperm membrane and acrosomal integrity and mitochondrial membrane potential (MMP) were assessed by SYBR-14/Propidium iodide, Alexa Fluor-488-PNA conjugate and JC-1, respectively. The total motility, acrosomal integrity, membrane integrity and MMP values were compared among cooling rates and extenders. Both cooling rate and type of extender had significant effect on cryosurvival (P<0.05). Sperm motility increased as cooling rate was increased for both strains (P<0.05). Highest cryosurvival was achieved when 100 °C/min cooling rate was used in combination with TES extender containing 20% egg yolk, 0.75% Equex paste and either 0.1 M sucrose or raffinose (P < 0.05). This study showed that TES extender containing 0.1 M raffinose or sucrose with 70 °C /min and 100 °C /min cooling rate improved post-thaw motility of rat sperm.

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Section: Introductionmentioning

confidence: 99%

The effects of cooling rates and type of freezing extenders on cryosurvival of rat sperm

2013

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“…4 This 'cold shock' effect results in an irreversible loss of motility. 5 'Cold shock' can be prevented by controlling the rate of cooling and by adding protective compounds to semen extenders such as egg yolk. 5,6 Pace and Graham 7 purified egg yolk and observed that the low-density lipoprotein (LDL) fraction showed cryoprotective properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of low-density lipoproteins, spermatozoa concentration and glycerol on functional and motility parameters of bull spermatozoa during storage at 4 °C

Vera-Munoz¹,

Amirat-Briand²,

Bencharif³

et al. 2010

Asian J Androl

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An extender has been developed with low-density lipoproteins (LDLs) that eliminates the microbial risks associated with the use of whole egg yolk. The objective of this study was to assess the effects of substituting egg yolk with LDLs for use as an extender in sperm preservation at 4 6C, as well as on spermatozoa motility, plasma membrane and acrosome integrity, at two different concentrations (80310 6 and 240310 6 sperm per ml) for 8 days and to evaluate glycerol toxicity in both extenders. A total of 12 ejaculates were collected from three bulls. Spermatozoa motility was examined using computer-assisted semen analysis. Plasma membrane integrity was determined using the hypo-osmotic swelling test and acrosome integrity with the fluorescein isothiocyanate-Pisum sativum agglutinin test. The semen was subsequently divided into four aliquots and diluted with Tris-egg yolk-glycerol (TEG), Tris-egg yolk without glycerol (TE), LDL with glycerol (LDL 1 ) and LDL without glycerol (LDL 2 ), at 80310 6 and 240310 6 sperm per ml. This study showed that the LDL 1 and LDL 2 extenders were more effective at preserving spermatozoa motility, plasma membrane integrity and acrosome integrity than TEG and TE (P,0.05) during 8 days of incubation. After 3 days of incubation, a toxicity of glycerol was observed in TEG, whereas no significant difference was observed between LDL 1 and LDL 2 . We can therefore conclude that the LDL extender can be used to refrigerate semen at 4 6C instead of TEG and TE at 80310 6 and 240310 6 sperm per ml for elite bulls. This finding can be used to define a policy for the storage of high-quality bull semen.

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“…Cholesterol plays an important role in the thermotropic behavior of the membranes [6] by preventing the molecular packing of the phospholipids (which is required to form the gel phase) as the temperature decreases [7] and minimizing cooling shock. Spermatozoa treated with CLC prior to cryopreservation are currently frozen using standard freezing extenders characterized by a high EY concentration.…”

mentioning

confidence: 99%

Egg Yolk and Glycerol Requirements for Freezing Boar Spermatozoa Treated with Methyl β-Cyclodextrin or Cholesterol-loaded Cyclodextrin

et al. 2014

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Egg yolk (EY) and glycerol are common constituents of extenders used for sperm cryopreservation. It has been demonstrated that using cholesterol-loaded cyclodextrins (CLC) improves sperm cryosurvival in several species. However, standard freezing extenders might not be the most appropriate for CLC-treated sperm. This study evaluated the EY and glycerol requirements for freezing CLC-treated boar spermatozoa. Semen samples from 34 ejaculates coming from 4 boars were used. Each ejaculate was split into three aliquots: one was used untreated (control), and the other two were treated with 1 mg of CLC or methyl-β-cyclodextrin/120 × 106 sperm for 15 min at 22 C prior to cryopreservation. Our results indicated that reducing the concentration of EY was detrimental for sperm viability after thawing (31.57 ± 2 vs. 19.89% ± 2 for 20 and 10% EY, respectively; P <0.05), even in semen treated with CLC. On the other hand, it was observed that the traditional concentration of glycerol (3%) was not the appropriate for freezing CLC-treated sperm (61.10 ± 3 vs. 47.87% ± 3 viable sperm for control and CLC-treated sperm, respectively; P <0.05). Thus, CLC-treated sperm showed a higher tolerance to high glycerol concentrations (5%) in terms of sperm viability (59.19% ± 3) than non-treated sperm (45.58% ± 3; P<0.05). Therefore, it could be necessary to modify the freezing extenders for CLC-treated sperm. Nevertheless, additional studies will be needed to evaluate alternative cryoprotectants and to determine the effect of high glycerol concentrations on sperm functionality.

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Hypothermia and Mammalian Gametes

Cited by 36 publications

References 93 publications

The effects of cooling rates and type of freezing extenders on cryosurvival of rat sperm

The effects of cooling rates and type of freezing extenders on cryosurvival of rat sperm

Effect of low-density lipoproteins, spermatozoa concentration and glycerol on functional and motility parameters of bull spermatozoa during storage at 4 °C

Egg Yolk and Glycerol Requirements for Freezing Boar Spermatozoa Treated with Methyl β-Cyclodextrin or Cholesterol-loaded Cyclodextrin

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