Effect of caloric restriction and rapamycin on ovarian aging in mice

Caloric restriction (CR) increases the preservation of the ovarian primordial follicular reserve, which can potentially delay menopause. Rapamycin also increases preservation on the ovarian reserve, with similar mechanism to CR. Therefore, the aim of our study was to evaluate the effects of rapamycin and CR on metabolism, ovarian reserve, and gene expression in mice. Thirty-six female mice were allocated into three groups: control, rapamycin-treated (4 mg/kg body weight every other day), and 30% CR. Caloric restricted females had lower body weight (P < 0.05) and increased insulin sensitivity (P = 0.003), while rapamycin injection did not change body weight (P > 0.05) and induced insulin resistance (P < 0.05). Both CR and rapamycin females displayed a higher number of primordial follicles (P = 0.02 and 0.04, respectively), fewer primary, secondary, and tertiary follicles (P < 0.05) and displayed increased ovarian Foxo3a gene expression (P < 0.05). Despite the divergent metabolic effects of the CR and rapamycin treatments, females from both groups displayed a similar increase in ovarian reserve, which was associated with higher expression of ovarian Foxo3a.

Giant panda (Ailuropoda melanoleuca) sperm morphometry and function after repeated freezing and thawing

This work examines the effects of subsequent cycles of freezing-thawing on giant panda (Ailuropoda melanoleuca) sperm morphometry and function, and assesses whether density-gradient centrifugation (DGC) can increase the number of freezing-thawing cycles this sperm can withstand. A sperm sample was collected by electroejaculation from a mature giant panda and subjected to five freezing-thawing cycles. Although repeated freezing-thawing negatively affected (P < 0.05) sperm motility and membrane integrity, in both nonselected and DCG-selected sperm samples, >60% of the sperm cells in both treatments showed acrosome integrity even after the fifth freezing cycle. In fresh semen, the sperm head length was 4.7 μm, the head width 3.6 μm, area 14.3 μm(2) and perimeter length 14.1 μm. The present results suggest that giant panda sperm trends to be resistant to repeated freezing-thawing, even without DGC selection.

Growth hormone increases DNA damage in ovarian follicles and macrophage infiltration in the ovaries

Evidence points to an important role of the growth hormone (GH) in the aging process and longevity. GH-deficient mice are smaller, live longer than normal littermates, and females have an increased ovarian reserve. The aim of the study was to evaluate the role of GH in the ovarian reserve by evaluating DNA damage, macrophage infiltration, and granulosa cell number in primordial and primary follicles. Experiment 1 used GH-deficient Ames dwarf mice (df/df, n = 12) and their normal littermates (N/df, n = 12), receiving GH or saline injections. Experiment 2 included transgenic mice overexpressing bovine GH (bGH) (n = 6) and normal mice (N, n = 6). DNA damage (anti-γH2AX) and macrophage counting (anti-CD68) were evaluated by immunofluorescence. Female df/df mice had lower γH2AX foci intensity in both oocytes and granulosa cells of primordial and primary follicles (p < 0.05), indicating fewer DNA double-strand breaks (DSBs). GH treatment increased DSBs in both df/df and N/df mice. Inversely, bGH mice had a higher quantity of DSBs in both oocytes and granulosa cells of primordial and primary follicles (p < 0.05). Df/df mice showed ovarian tissue with less macrophage infiltration than N/df mice (p < 0.05) and GH treatment increased macrophage infiltration (p < 0.05). In contrast, bGH mice had ovarian tissue with more macrophage infiltration compared to normal mice (p < 0.05). The current study shows that GH increases DNA DSBs in oocytes and granulosa cells and raises macrophage infiltration in the ovaries, pointing to the role of the GH/IGF-I axis in maintenance of oocyte DNA integrity and ovarian macrophage infiltration in mice.

Cryopreservation of margay (Leopardus wiedii) spermatozoa: Effects of different extenders and frozen protocols

Sperm cryopreservation offers many benefits to wild felids conservation programs. However, the implementation of these programs is limited by the different responses of each species to the cryopreservation protocols and extenders used, requiring the formulation of species-specific protocols. For this purpose, semen samples from 6 margays (Leopardus wiedii) were submitted to 2 cryopreservation protocols: 1) manual freezing (cooling rate of - 0.33 °C/min at 5 °C/180 min and freezing rate with two steps - 9 °C/min for 2 min and -19.1 °C/min for 2 min) and 2) automatic freezing machine (cooling rate of - 0.25 °C/min at 5 °C/120 min and freezing rate with one step -20 °C/min for 8.3 min) using 2 commercial extenders, an egg yolk-based (Test Yolk Buffer; TYB) and an egg yolk-free extender (AndroMed; MED). Post-thawed sperm quality was assessed at 3 time points (immediately after thawing and 1 and 2 h post-thawed) by sperm motility index (SMI), plasma membrane and acrosomal integrity, and mitochondrial membrane potential (MMP). Regarding SMI, TYB yielded superior results (29.4 ± 3.5%) compared to MED (11.2 ± 2.8%; p < 0.002) immediately after thawing until 2 h after thawing (TYB 3.9 ± 1.7% and MED 0.0 ± 0.0%; p < 0.05). Furthermore, the automated freezing method provided higher motility compared to the manual freezing procedure immediately post-thaw (25.08 ± 3.66% and 15.78 ± 3.29%, respectively) and 1 h post-thaw (13.71 ± 2.56% and 6.03 ± 1.97%, respectively; p < 0.05). The percentage of intact acrosomes and plasma membranes and the percentage of sperm with high MMP were superior for TYB when compared to MED regardless of cryopreservation protocol (p < 0.05). Conversely, the interaction between cryopreservation protocols and extenders was observed for MMP where TYB exhibits better results compared to MED (p < 0.05) in both procedures, but it was higher in automated procedures. For MED, no changes were found in MMP between procedures. Considering only TYB, samples showed higher MMP when submitted to an automated procedure (p < 0.05). In conclusion, the slow cooling rates with shorter time of exposure to glycerol contributed to minimize cryodamage in the Margays' sperm. Moreover, results indicated that association between TYB and automatic freezing machine ensured the minimal quality of spermatozoa after thawing required for further use in in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Dasatinib and quercetin increase testosterone and sperm concentration in mice

Cellular senescence is a defense mechanism to arrest proliferation of damaged cells. The number of senescent cells increases with age in different tissues and contributes to the development of age-related diseases. Old mice treated with senolytics drugs, dasatinib and quercetin (D+Q), have reduced senescent cells burden. The aim of this study was to evaluate the effects of D+Q on testicular function and fertility of male mice. Mice (n = 9/group) received D (5 mg kg-1) and Q (50 mg kg-1) via gavage every moth for three consecutive days from 3 to 8 months of age. At 8 months mice were breed with young non-treated females and euthanized. The treatment of male mice with D+Q increased serum testosterone levels and sperm concentration and decreased abnormal sperm morphology. Sperm motility, seminiferous tubule morphometry, testicular gene expression and fertility were not affected by treatment. There was no effect of D+Q treatment in β-galactosidase activity and in lipofuscin staining in testes. D+Q treatment also did not affect body mass gain and testes mass. In conclusion, D+Q treatment increased serum testosterone levels and sperm concentration and decreased abnormal sperm morphology, however did not affect fertility. Further studies with older mice and different senolytics are necessary to elucidate the effects in the decline of sperm output (quality and quantity) associated with aging.

Calorie restriction during gestation affects ovarian reserve in offspring in the mouse

The aim of this study was to investigate the effect of calorie restriction (CR) during pregnancy in mice on metabolism and ovarian function in the offspring. Pregnant female mice were divided into two groups, a control group and a CR group (n=7 in each). Mice in the CR group were fed 50% of the amount consumed by control females from Day 10 of gestation until delivery. After weaning, the offspring received diet ad libitum until 3 months of age, when ovaries were collected. Ovaries were serially cut and every sixth section was used for follicle counting. Female offspring from CR dams tended to have increased bodyweight compared with offspring from control females (P=0.08). Interestingly, fewer primordial follicles (60% reduction; P=0.001), transitional follicles (P=0.0006) and total follicles (P=0.006) were observed in offspring from CR mothers. The number of primary, secondary and tertiary follicles did not differ between the groups (P>0.05). The CR offspring had fewer DNA double-strand breaks in primary follicle oocytes (P=0.03). In summary, CR during the second half of gestation decreased primordial ovarian follicle reserve in female offspring. These findings suggest that undernutrition during the second half of gestation may decrease the reproductive lifespan of female offspring.

Spermiotoxicity of commercial condoms made from polyurethane, polyisoprene and latex, using domestic ruminants as an experimental animal model

The use of condoms could provide a means of collecting high-quality spermatozoa from different species under physiological ejaculation conditions. However, certain condom materials may affect sperm functionality. This study examined the spermiotoxicity of different commercial condom materials towards ram and goat spermatozoa. Sperm samples were diluted in Tyrode's medium and placed in contact with a piece of condom material (polyurethane, polyisoprene or latex) and incubated for 30 or 90 min. Contact time in the polyisoprene and latex treatments affected some sperm variables; no such effects were seen, however, in the polyurethane treatments. For ram spermatozoa in contact with polyisoprene, the percentage of dead spermatozoa with a damaged acrosome increased at 90 min, while for spermatozoa in contact with latex, the percentage of live spermatozoa with an intact acrosome decreased. For goat spermatozoa in contact with both polyisoprene and latex, the percentage of dead spermatozoa with a damaged acrosome increased at 90 min, while for spermatozoa in contact with polyisoprene, the percentage of live spermatozoa with an intact acrosome decreased. In conclusion, latex and polyisoprene contain components that affect sperm motility, plasma membrane integrity and acrosome function. Polyurethane does not seem to reduce the quality of semen.

EFFECT OF CALORIC RESTRICTION AND RAPAMYCIN ON OVARIAN AGING IN MICE

The ovarian follicular reserve of primordial follicle declines with aging in female mammals. Caloric restriction (CR) has been shown to increase the preservation of the ovarian follicular reserve. Likewise, rapamycin has similar effects to CR on the ovarian reserve. Therefore, the aim of our study was to evaluate the effects of rapamycin and CR on the metabolism and ovarian follicular reserve and gene expression in mice. Thirty-six female mice were used, and allocated into 3 groups: control, rapamycin (4mg/kg body weight every other day) and 30% CR. At 85 days of treatment, an insulin tolerance test (ITT) and glucose tolerance test (GTT) was performed. At 93 days ovaries were collected for analysis. CR females had lower body weight (P<0.05) and were more insulin sensitive (P=0.003), while rapamycin treated females did not change body weight (P>0.05) and were more resistant to insulin (P<0.05). Females from the CR and rapamycin groups had a twice higher number of primordial follicles (P=0.02 and 0.04) and half the number of primary, secondary and tertiary follicles (P<0.05). Both CR and rapamycin females had increased ovarian gene expression of Foxo3a mRNA (P<0.05). In conclusion, female mice from rapamycin and CR groups had an increased ovarian follicular reserve associated to higher expression of Foxo3a mRNA, despite divergent metabolic effects of the treatments.

94 USE OF β-MERCAPTOETHANOL AND CYSTEINE FOR IN VITRO MATURATION AND CULTURE OF SHEEP EMBRYOS

During in vitro production (IVP), embryos are sensitive to suffering negative effects from catabolites, such as reactive oxygen species (ROS). Under physiological conditions, the action of the ROS is blocked by antioxidants such as glutathione, but glutathione's concentration is reduced during the main steps of the IVP process. The objective of the present study is to evaluate the effect of the supplementation of the media for in vitro maturation (IVM) and in vitro culture (IVC) with β-mercaptoethanol and cysteine on the rates of embryo development and viability after vitrification in open pulled straws (OPS). Ten IVP routines were conducted for IVP, using ovaries form pubertal sheep collected in a slaughterhouse. The ovaries were kept in a saline/antibiotic solution at 30°C during transport to the laboratory. The cumulus oophurus–oocytes complexes (COC) selected for IVM were allocated to 2 treatments: T1 (control), including no antioxidants in the IVM and IVC media (n = 676); and T2, including 50 μM β-mercaptoethanol and 600 μM cysteine, in the IVM and IVC media (n = 729). The IVM was conducted using the TCM 199 medium including oestradiol, FSH, LH, pyruvate, heat inactivated sheep serum and antibiotics, for 22 to 24 h. Sperm selection was conducted by swim-up in medium with tris-glucose-citric acid with fresh semen. For IVF, conducted for 18 to 22 h, 1 × 106 spermatozoa per mL were used in SOF medium including 2% heat-inactivated sheep serum. Both IVM and IVF were conducted with incubation with 5% CO2 at 39°C with saturated humidity. After IVF, the probable zygotes were denuded and cultured for 8 days in SOF medium with 0.4% BSA, at 39°C, in bags with 3 gases (5% CO2, 90% N2 and 5% O2). The criteria considered for embryo viability were: cleavage rate at Day 2 (cleaved/inseminated), embryo development at Day 7 (blastocysts/cleaved) and the reexpansion rate 24 h post-vitrification. Such frequencies were compared between treatments by the chi-squared test. The cleavage rate did not differ (P > 0.05) for T1 (60.3%) and T2 (64.3%). The rate of embryro development at Day 7 was also similar (P > 0.05) for T1 (33.6%) and T2 (36.6%). The reexpansion rate for T1 (76.9%) and T2 (54.1%) were also similar (P > 0.05). Thus, supplementation of IVM and IVC media with β-mercaptoethanol and cysteine presented no effect in the development and viability of vitrified sheep embryos. CAPES, MARFRIG Group.