The Infertility of Repeat-Breeder Cows During Summer Is Associated with Decreased Mitochondrial DNA and Increased Expression of Mitochondrial and Apoptotic Genes in Oocytes.

Oocyte quality is known to be a major cause of infertility in repeat-breeder (RB) and heat-stressed dairy cows. However, the mechanisms by which RB oocytes become less capable of supporting embryo development remain largely unknown. Thus, the aim of this study was to investigate whether the decreased oocyte competence of RB cows (RBs) during summer is associated with an altered gene expression profile and a decrease in mitochondrial DNA (mtDNA) copy number. Therefore, oocytes collected from heifers, non-RBs in peak lactation (PLs), and RBs were used to evaluate mtDNA amounts as well as the expression levels of genes associated with the mitochondria (MT-CO1, NRF1, POLG, POLG2, PPARGC1A, and TFAM), apoptosis (BAX, BCL2, and ITM2B), and oocyte maturation (BMP15, FGF8, FGF10, FGF16, FGF17, and GDF9). The oocytes retrieved from RBs during winter contained over eight times more mtDNA than those retrieved from RBs during summer. They also contained significantly less mtDNA than oocytes retrieved from heifers and PLs during summer. Moreover, the expression of mitochondria- (NRF1, POLG, POLG2, PPARGC1A, and TFAM) and apoptosis-related (BAX and ITM2B) genes, as well as of GDF9, in RB oocytes collected during summer was significantly greater than that in oocytes collected from heifers and PLs during the same season. In oocytes from heifers and PLs, the expression levels of these genes were lower in those collected during summer compared with winter, but this difference was not observed in oocytes collected from RBs. Altogether, these data provide evidence of altered gene expression and reduced mtDNA copy number in the oocytes collected from RBs during summer. This indicates a loss of fertility in RBs during summer, which might be caused by a possible mitochondrial dysfunction associated with a greater chance of oocytes to undergo apoptosis.

Toxoplasma gondii: Evidence for the transmission by semen in dogs.

Ten male dogs were distributed into three experimental groups for infection with Toxoplasma gondii: GI - three dogs inoculated with 2.0x10(5) P strais oocysts, GII - three dogs infected with 1.0x10(6) RH strain tachyzoites, and GIII - four controls dogs. Several clinical parameters were evaluated. IFAT was performed to detect anti-T. gondii antibodies. Presence of the parasite in semen was evaluated by PCR and bioassay techniques. Tissue parasitism was examined using bioassays and immunohistochemistry in testicle and epididymis fragments collected after orchiectomy. In semen samples collected from these two groups, the presence of T. gondii was verified by bioassays and PCR. T. gondii was detected by immunohistochemistry in tissues (testicle and epididymis fragments) of all six experimentally infected dogs. The T. gondii-positive seminal samples were used in the artificial insemination (AI) of four female dogs free of toxoplasmic infection. Seven days after AI, all of the female dogs presented serologic conversion (IFAT). Fetal reabsorption occurred in two of the dogs, while the others sustained full-term gestation. Several T. gondii cysts were detected in the brains of four offspring. These results suggest that T. gondii can be sexually transmitted in domestic dogs.

Use of FSH in two different regimens for ovarian superstimulation prior to ovum pick up and in vitro embryo production in Holstein cows.

We aimed with the present study to evaluate the effects of FSH treatment (200 mg) split in four or six administrations on ovarian follicle stimulation and in vitro oocyte competence for embryo production in dairy cows with synchronized follicular wave emergence. On random days of the estrous cycle (Day 0), non-lactating Holstein cows received a progesterone (P4)-releasing intravaginal device and 2 mg estradiol benzoate IM. On Day 3, they received 0.530 mg sodium cloprostenol (PGF2α) IM. Control cows (n = 35) received no further treatments, whereas FSH-treated cows received 200 mg FSH split in four (FSH4 group; n = 33) or six (FSH6 group; n = 33) administration regimens. Starting on Day 4, cows in FSH4 group received 200 mg FSH split in four equivalent doses of 50 mg 12 h apart. Cows in FSH6 group received the same total FSH dose split in six equivalent doses of 33.3 mg 12 h apart, but treatments started on Day 3. On Day 7 AM (36 h of "coasting" period for FSH-treated groups), the P4 devices were removed and cows were subjected to ovum pick up (OPU). Viable oocytes were in vitro fertilized using sexed-sorted semen. Although FSH treatment did not (P > 0.1) increase the total number of follicles (Control, 53.2 ± 4.5 vs. FSH-treated, 51.4 ± 3.1), the two hormonal stimulation regimens, FSH4 and FSH6, increased the number of medium follicles (6-10 mm; 5.2 ± 0.5 vs. 18.1 ± 1.4; P < 0.0001) and reduced the number of small follicles (2-5.9 mm; 46.3 ± 5.1 vs. 31.0 ± 2.4 P < 0.0001). Also, FSH treatment or regimen did not increase (P > 0.1) the number of viable oocytes (Control, 12.6 ± 1.26 vs. FSH-treated, 12.70 ± 1.03), recovery rate (Control, 36.5% vs. FSH-treated, 36%) and the number of in vitro produced blastocyst (Control, 4.1 ± 0.52 vs. FSH-treated 4.3 ± 0.5). We concluded that FSH stimulation protocol proposed herein is effective to stimulate the growth of small antral follicle population prior to OPU, but it was ineffective to improve in vitro oocyte competence for embryo production in non-lactating Holstein cows with synchronized follicular wave emergence.

Reference gene selection for gene expression analysis of oocytes collected from dairy cattle and buffaloes during winter and summer.

Oocytes from dairy cattle and buffaloes have severely compromised developmental competence during summer. While analysis of gene expression is a powerful technique for understanding the factors affecting developmental hindrance in oocytes, analysis by real-time reverse transcription PCR (RT-PCR) relies on the correct normalization by reference genes showing stable expression. Furthermore, several studies have found that genes commonly used as reference standards do not behave as expected depending on cell type and experimental design. Hence, it is recommended to evaluate expression stability of candidate reference genes for a specific experimental condition before employing them as internal controls. In acknowledgment of the importance of seasonal effects on oocyte gene expression, the aim of this study was to evaluate the stability of expression levels of ten well-known reference genes (ACTB, GAPDH, GUSB, HIST1H2AG, HPRT1, PPIA, RPL15, SDHA, TBP and YWHAZ) using oocytes collected from different categories of dairy cattle and buffaloes during winter and summer. A normalization factor was provided for cattle (RPL15, PPIA and GUSB) and buffaloes (YWHAZ, GUSB and GAPDH) based on the expression of the three most stable reference genes in each species. Normalization of non-reference target genes by these reference genes was shown to be considerably different from normalization by less stable reference genes, further highlighting the need for careful selection of internal controls. Therefore, due to the high variability of reference genes among experimental groups, we conclude that data normalized by internal controls can be misleading and should be compared to not normalized data or to data normalized by an external control in order to better interpret the biological relevance of gene expression analysis.

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG? / Suplementação com LH modifica a taxa e momento da ovulação e a produção de embriões em ovelhas Santa Inês superovuladas com FSH e eCG?

The objective was to evaluate if supplemental LH given at the end of FSH treatment would synchronize the time of ovulation and increase the ovulation rate and embryo yield in Santa Ines ewes. Twenty superovulatory (SOV) programs were accomplished in cross-over design (60d interval). On D0, a CIDR device was inserted, and the device was replaced with a new one 7 days later, when 37.5µg of d-cloprostenol was administered. On D12, we started the SOV treatment, administering 256mg of pFSH 8 times, 12h apart. On D14, the CIDR was removed, and 200IU of eCG and 37.5µg of d-cloprostenol were administered. On D15, the ewes were allocated into one of two groups, a Control group (n=10) that received no supplemental LH and a LH group (n=10) treated with 7.5mg of LH 24h after CIDR removal. Artificial inseminations (AI) were performed 42 and 48h after CIDR removal. The ovarian structures were evaluated by laparoscopy immediately before each AI and 5 days later (D21) when the embryos were collected. The LH ewes ovulated more frequently (P=0.05) before 42h than between 42 and 48h. Treatment with LH tended to increase the frequency of CL and to decrease the anovulatory follicles (P=0.08). The supplemental LH increased the frequency of ewes with a high SOV response (≥11 CL; P=0.05). In conclusion, supplemental LH increased the frequency of ewes with high SOV response and ovulating prior to 42h, however, there was no synchrony between ovulations. The supplemental LH also decreased the frequency of anovulatory follicles, although the ovulation rate and embryo yield were unaffected.

O objetivo deste trabalho foi avaliar se a suplementação com LH ao final do tratamento gonadotrófico sincroniza o tempo das ovulações e incrementa a taxa de ovulação e produção de embriões em ovelhas Santa Inês. Vinte programas de superovulação (SOV) foram realizados em delineamento cross-over (intervalo de 60 dias). No D0, um CIDR foi inserido, sendo trocado por um novo sete dias após, quando 37,5µg de d-cloprostenol foram administradas. No D12, iniciou-se o tratamento com 256mg de pFSH em 8 administrações (12/12h). No D14, o CIDR foi retirado, 200UI de eCG e 37,5µg de d-cloprostenol foram administradas. No D15, as ovelhas foram alocadas em um dos dois grupos: Controle (n=10), sem suplementação com LH, e LH (n=10), tratado com 7,5mg de LH, 24h após a remoção do CIDR. Inseminações artificiais (IA) foram realizadas 42 e 48h após a remoção do CIDR. As estruturas ovarianas foram avaliadas por laparoscopia imediatamente antes de cada IA e 5 dias após, quando os embriões foram colhidos. As ovelhas que receberam o LH tiveram maior frequência de ovulações antes de 42h (P=0,05). O tratamento com LH tendeu em incrementar a frequência de CL e diminuir a de folículos anovulatórios (P=0,08). A suplementação com LH incrementou (P=0,05) a frequência de ovelhas com alta resposta superovulatória (≥11 CL; P=0,05). Em conclusão, a suplementação com LH incrementou a frequência de ovelhas com alta resposta e ovulações antes de 42h depois da remoção do CIDR, entretanto, não houve sincronia entre as ovulações. A suplementação diminuiu a frequência de folículos anovulatórios, embora a taxa de ovulação e a produção de embriões permaneceram inalteradas.

Histopathological analysis of the reproductive system of male dogs experimentally infected with Toxoplasma gondii / Análise histopatológica do sistema reprodutor de cães machos experimentalmente infectados com Toxoplasma gondii

The present research aimed to describe possible histopathological alterations in the reproductive system (testicles and epididymis) of male dogs experimentally infected with Toxoplasma gondii. Canines (n=10) serologically negative for T. gondii were selected and distributed into three experimental groups: GI, 3 inoculated with 2.0 x 10(5)P strain oocysts; GII, 3 infected with 1.0 x 10(6)RH strain tachyzoites; and GIII, 4 control dogs. Antibody research (IFAT) against T. gondii was realized. Toxoplasma gondii infection was confirmed by seroconversion of the 6 males infected with tachyzoites and oocysts from postinoculation day (PID) 7 and 14, respectively. At PID 70, all dogs were submitted to orchiectomy and testicle and epididymis samples were collected and histologically processed for examination under optical microscope. The following alterations were diagnosed: mild and moderate mononuclear inflammatory infiltrate in the epididymis, moderate cellular edema, hydropic degeneration and moderate interstitial fibrosis in seminiferous tubules. The histopathological results in the present research, isolation of T. gondii in testicle and epididymis fragments by immunohistochemistry and results from the literature by other authors in different tissues, all infer that the alterations observed in dogs infected with T. gondii are suggestive of toxoplasmic infection.

O presente trabalho teve como objetivo descrever eventuais alterações histopatológicas no sistema reprodutor (testículo e epidídimo) de cães machos experimentalmente infectados com Toxoplasma gondii. Para tal, 10 animais sorologicamente negativos para T. gondii foram selecionados e distribuídos em três grupos experimentais: GI - três cães inoculados com 2,0 x 10(5) oocistos da cepa P, GII - três cães infectados com 1,0 x 10(6) taquizoítos da cepa RH e GIII - quatro cães mantidos como controle. Pesquisa de anticorpos (IFI) contra T. gondii foi realizada. A infecção por T. gondii confirmou-se pela soroconversão de todos os machos infectados a partir do 7° e do 14° dia pós-inoculação (DPI) para cães que receberam taquizoítos e oocistos respectivamente. Decorridos 70DPI, realizou-se, em todos os cães, orquiectomia, e amostras (testículo e epidídimo) foram coletadas e processadas histologicamente para leitura em microscópio óptico. As seguintes alterações foram diagnosticadas: infiltrado inflamatório mononuclear leve e moderado em epidídimo, edema celular moderado, degeneração hidrópica e fibrose intersticial moderada em túbulos seminíferos. Os resultados histopatológicos do presente trabalho, aliados ao isolamento do T. gondii em fragmentos de testículo e epidídimo pela imunoistoquímica, juntamente com os resultados encontrados na literatura por outros autores em diferentes tecidos, permitem inferir que as alterações encontradas nos cães infectados com o respectivo protozoário são sugestivas de infecção toxoplásmica.