Effect of heat exposure on prostaglandin production and expression of COX-2, PGES, PGFS, ITGAV and LGALS15 mRNAs in endometrial epithelial cells of buffalo (Bubalus bubalis)

BACKGROUND

Early embryonic mortality is one of the major intriguing factors of reproductive failure that causes considerable challenge to the mammalian cell biologists. Heat stress is the major factor responsible for reduced fertility in farm animals. The present study aimed to investigate the influence of heat stress on prostaglandin production and the expression of key genes, including COX-2, PGES, PGFS, ITGAV and LGALS15, in buffalo endometrial epithelial cells.

METHODS AND RESULTS

Buffalo genitalia containing ovaries with corpus luteum (CL) were collected immediately post-slaughter. The stages of the estrous cycle were determined based on macroscopic observations of the ovaries. Uterine lumens of the mid-luteal phase (days 6-10 of the estrous cycle) were washed and treated with trypsin to isolate epithelial cells, which were then cultured at control temperature (38.5 °C for 24 h) or exposed to elevated temperatures [38.5 °C for 6 h, 40.5 °C for 18 h; Heat Stressed (HS)]. The supernatant and endometrial epithelial cells were collected at various time points (0, 3, 6, 12, and 24 h) from both the control and treatment groups. Although heat stress (40.5 °C) significantly (P < 0.05) increased COX-2, PGES, and PGFS transcripts in epithelial cells but it did not affect the in vitro production of PGF2α and PGE2. The expression of ITGAV and LGALS15 mRNAs in endometrial epithelial cells remained unaltered under elevated temperature conditions.

CONCLUSION

It can be concluded that elevated temperature did not directly modulate prostaglandin production but, it promoted the expression of COX-2, PGES and PGFS mRNA in buffalo endometrial epithelial cells.

Low oxygen tension activates glucose metabolism, improves antioxidant capacity and augment developmental potential of ovine embryos in vitro

Context Oxygen (O2) is one of the most powerful regulators of embryo function. Nevertheless, most in vitro embryo production studies do not consider O2 as a determining factor. Aim The present study was designed to assess the effect of different O2 (5 and 20%) concentrations on the developmental ability and expression of genes related to cellular antioxidant functions and glucose metabolism in the in vitro produced ovine embryos. Methods In vitro sheep embryos were produced at different O2 (5 and 20%) concentrations as per the laboratory protocol. Developmental stages of embryos at different O2 concentrations were compared. Messenger RNA abundance of antioxidant and glucose metabolism genes in embryos produced at different O2 concentrations were compared. Key results No significant (P &lt; 0.05) effect of different O2 concentrations on oocyte maturation and cleavage rate was observed. In contrast, significantly (P &lt; 0.05) more number of morula and blastocysts were observed at 5 compared with 20%O2. The expression level of the genes related to antioxidant functions (GPX, SOD1, SOD2 and CAT) and glucose metabolism (G6PD and HPRT) were found significantly (P &lt; 0.05) greater in the embryos generated with 5 compared with 20% O2. In contrast, the expression of GAPDH did not differ significantly (P &lt; 0.05) between the groups. Conclusions Ovine embryos at 5%O2 generated low ROS and synthesised more GSH due to the activation of G6PD and GPX that in turn increased the antioxidant capability and developmental potential of the embryos. Implications Embryos at higher O2 concentration (20%) generated more reactive oxygen species (ROS) that caused oxidative damage to the embryos and in turn reduced their developmental ability and alter gene expression.

Suppression of COX-2 mRNA abundance in in vitro cultured goat (Capra hircus) endometrial cells by RNA interference and effect on PGF2-α and PGE2 concentrations

Cyclooxygenase-2 (COX-2) has important functions in the synthesis and release of endometrial prostaglandin F2α (PGF2α). Excessive production of COX-2 leads to an increase in endometrial PGF2α synthesis and subsequently causes luteolysis and early embryonic mortality. The aim of this study was to investigate in goats the effects of COX-2 small interference RNA (siRNA) on COX-2 mRNA abundance and the secretion of PGF2α and PGE2 in goat endometrial cells. Endometrial cells isolated from goat uteri were cultured at 38.5 °C and 5% CO₂. The cells were treated with different concentrations (0, 10, 25, 50, 100, 250, 500, 750 and 1000 nM per well) of three different COX-2 siRNAs at confluency for 24 h. At 24 h post culture, COX-2 mRNA abundance was quantified using qPCR and PGF2α and PGE2 concentrations were quantified in the culture medium. There was a lesser relative abundance of COX-2 mRNA in endometrial cells at 100 to 1000 nM siRNA. The greatest extent of abundance suppression, however, was observed with 1000 nM siRNA. Transfection of COX-2 siRNA (1000 nM) to endometrial cells suppressed the COX-2 mRNA abundance by 77%, 82%, and 84% with siRNA 1, 2, 3, respectively. Furthermore, with COX-2 siRNA transfected cells, there was a lesser (P < 0.05) PGF2α concentration than in cells not transfected, whereas PGE₂ secretion was not affected. The results of the study provide evidence that COX-2 siRNA used in this study suppresses COX-2 mRNA abundance and PGF2α secretion but there was no association between PGE2 concentrations and COX-2 mRNA abundance in goat endometrial epithelial cells.

Advancement of puberty and enhancement of seminal characteristics by supplementation of trace minerals to bucks

Attainment of puberty in animals is dependent on their age, body weight, nutritional status, genetic and environmental conditions. Nutritionally, organic minerals are suggested to improve semen production, sperm motility and male fertility. In this context, role of organic zinc (Zn) and copper (Cu) in advancing male puberty and semen characters in Osmanabadi goats were studied. Forty one (n = 41) bucks (Aged 5 months) were divided into ten groups and the dietary treatments comprised of a control group (basal diet; without additional trace mineral supplementation) and nine treatment groups that received, in addition to the basal diet, various doses of trace minerals (mg) on per kg dry matter basis, organic Zn as low Zn20, medium Zn40 and high Zn60, organic Cu as low Cu12.5, medium Cu25, high Cu37.5 and combination of organic Zn + Cu as low Zn20 + Cu12.5, medium Zn40 + Cu25, high Zn60 + Cu37.5, respectively fed for a period of 8 months. Bucks fed organic trace minerals reached puberty 28-35 days earlier than control group. In addition, improvement (P < .01) in testosterone hormone (ng/ml) levels (control: 1.63 ± 0.07 VS Zn60: 2.54 ± 0.02; Cu12.5: 6.17 ± 0.05; Cu25: 3.01 ± 0.04; Cu37.5: 2.39 ± 0.06; Zn20 + Cu12.5: 1.94 ± 0.02; Zn60 + Cu37.5: 2.44 ± 0.16 at 240 days), semen production capacity (sperm concentration, volume, mass motility) and semen quality (higher progressive motility, velocity, sperm membrane integrity and acrosome integrity) were observed in supplemented groups (P < .05) than the control bucks. The present study demonstrated that, additional feeding of organic Zn and Cu to growing male goats advanced onset of puberty and improved quantitative and qualitative semen characteristics. The results also implied that the organic Cu had a significant effect on overall performances of bucks as compared to Zn alone or Zn and Cu in combination.

Relationship of organic mineral supplementation and spermatozoa/white blood cells mRNA in goats

The antioxidant properties and the protective role of organic zinc (Zn) and copper (Cu) in white blood cells (WBCs) and spermatozoa were analyzed through quantification of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione peroxidase 4 (GPx4) and nuclear factor erythroid 2-like 2 (NFE2L2) and correlations were determined with sperm functional characteristics in Osmanabadi bucks. Bucks (aged 5 months; n = 40) were divided into ten groups, and the dietary treatments comprised of a control and nine treatment groups as follows: organic Zn as Zn 20, Zn 40 and Zn 60, organic Cu as Cu 12.5, Cu 25, Cu 37.5 and combined organic Zn and Cu as Zn 20+Cu 12.5, Zn 40+Cu 25, Zn 60+Cu 37.5, respectively per kg dry matter for a period of 8 months. The blood (120 and 240 days) and semen (240 days: 40 × 4 = 160) samples were collected from 40 bucks. In WBCs: the relative abundance of mRNA for SOD1, CAT, GPx4, NFE2L2 was greater (P < 0.05) in (120 and 240 days) in majority of the mineral supplemented animals. In spermatozoa: the relative abundance of SOD1, NFE2L2, GPx4 and CAT mRNA was greater (P < 0.05) in selected treatment groups. The abundance of SOD1 mRNA in WBCs was positively correlated (P <  0.05) with sperm mass motility (r = 0.692, P = 0.027). The abundance of GPx4 mRNA was negatively correlated (P <  0.05) with type A sperm (straightness; STR) > 85% and amplitude of lateral head displacement (ALH) > 2.5 μm/ s) (r = -0.711, P = 0.021) and (P <  0.05) positively correlated with sperm viability (r = 0.669, P = 0.035). Organic Zn and Cu supplementation was associated with an increase in the expression of antioxidant defense enzyme genes in bucks.

Molecular cloning and expression of FGF2 gene in pre-implantation developmental stages of in vitro-produced sheep embryos

Early embryonic mortality is one of the main sources of reproductive loss in domestic ruminants including sheep. Fibroblast growth factor-2 (FGF-2) is a member of FGFs family that mediates trophoblast activities and regulates embryonic development in various species. In this study, we have cloned, characterized sheep FGF2 cDNA (KU316368) and studied the expression in sheep embryos. Ovaries of non-pregnant sheep were collected from local abattoir and matured in culture medium at 38.5ºC, 5% CO₂ , 95% humidity for 22-24 hr. The matured oocytes were inseminated with capacitated spermatozoa in Brackett and Oliphant medium and resulted embryos were cultured in CO₂ incubator for 6-7 days to complete the developmental stages from two cells to blastocyst stage. Total RNA was extracted from immature oocytes (n = 100), mature oocytes (n = 100) and different stages of embryos such as 2 cell (n = 50), 4 cell (n = 25), 8 cell (n = 12), 16 cell (n = 6), morula (n = 5) and blastocyst (n = 3). The total RNA isolated from the oocytes and embryos was reverse transcribed and subjected to real-time polymerase chain reaction using sequence-specific primers and SYBR green as the DNA dye. On sequence analysis, the nucleotide sequence of sheep FGF2 exhibited highest sequence similarity with cattle (100%) and least with rat and mouse (69.2%). At the deduced amino acid level, a highest degree of similarity was noticed with cattle, buffalo, goat, pig, camel and horse (100%) and lowest degree of identity with rat, human and mouse (98.2%). The FGF2 mRNA expression was higher in immature and mature oocytes and gradually decreases from 2-cell stage of embryo to the blastocyst stage. More over a significant differences in FGF2 mRNA expression (p < .05) were observed between immature oocytes and all pre-implantation stages of embryo. It can be concluded that FGF-2 plays a significant role in pre-implantation and early development of embryos in sheep.

Maturation timing and fetal bovine serum concentration for developmental potential of sheep oocytes in vitro

The success of in vitro embryo production (IVEP) in animals has improved over time, employing a variety of culture media. Here, we assessed the maturation timing and developmental potential of sheep oocytes in vitro at different concentrations of fetal bovine serum (FBS): Cumulus oocyte complexes (COCs) were aspirated from follicles (2-6 mm) of sheep ovaries collected from local slaughter house. COCs were randomly divided into two groups and matured at 38.5'C, 5% CO2 for 24 h (Group I) and 27 h (Group II). Oocytes cultured for 27 h showed significantly (P <0.05) more maturation than those cultured for 24 h (82 vs. 76%) followed by more cleavage (35 vs. 30%), morula (53 vs. 39%) and blastocyst (17 vs. 11%) percentage. In the second experiment, oocytes were randomly divided into two groups and matured with 10% FBS (Group I) and 20% FBS (Group II) for 27 h supplemented with pyruvate, glutamine, LH, FSH and estradiol. After maturation, oocytes were fertilized by fresh semen for 18 h. Presumptive zygotes in both the groups were again divided into two groups and culturedin 10 and 20% FBS during post fertilization period, respectively. Different FBS concentration in maturation medium did not influence maturation percentage (82 vs. 79%) significantly. Out of culture groups, presumptive zygotes matured in 20% FBS and cultured in 20% FBS during post fertilization period showed significant increase in cleavage percentage (44 vs. 39, 35 and 27%) as compared to other groups but subsequent development to morula (55 vs. 53, 43 and 40%) and blastocyst (20 vs. 17, 16 and 15%) percentage were more in the group matured in 10% FBS and cultured in 20% FBS during post fertilization period.

Impact of nutritional stress on early embryonic survival

AbstractBackground: Low reproductive efficiency is the most critical problem faced by the livestock industry across the globe. Early embryonic loss is one the major cause of poor reproductive efficiency resulting in delayed pregnancy, fewer calves born, reduced milk production, slower genetic progress and substantial financial loss to the beef or dairy industry. The establishment of pregnancy results from the interaction between the embryo and the dam and is the culmination of a series of events initiated with development of the follicle and gametes. Among numerous internal and external factors nutrition has the potency to alter the micro-environment of the oocyte and the embryo, making it more hostile to optimal fertilization and pre-implantation embryonic growth. Understanding the impact of nutritional stress on oocyte function, embryo development and reciprocal signaling networks between the embryo and uterus will lead to alleviation of the problems of early embryonic mortality. Keywords:  Early embryonic loss, establishment of pregnancy, maternal recognition of pregnancy, interferon-tau, progesterone, nutritional stress, oocyte function, embryo development

Isolation and characterization of luteal cells in buffalo (Bubalus bubalis)

The objective of the study was to evaluate the morphological and functional characteristics of luteal cells isolated from buffalo ovary. Luteal cells exhibited columnar morphology and contact inhibition at the stage of confluence. Protein concentrations increased linearly from Day 3 to Day 7 of culture. DNA concentrations increased from Day 3 to Day 5 and then declined to Day 7 of culture. PGF2alpha concentrations decreased progressively from Day 3 to Day 7 of culture. It was concluded that buffalo luteal cells could serve as an excellent model for studying the specific role of PGF2alpha in maternal recognition of pregnancy and implantation.

Effect of prostaglandin producing modulators on in vitro growth of buffalo uterine epithelial cells

Studies were conducted to examine the effect of seven prostaglandin producing modulators on the in vitro growth of uterine epithelial cells in buffalo. The uterine epithelial cells isolated from slaughtered buffaloes were cultured in media containing a) Lipopolysaccaride (LPS): 0, 0.01, 0.1, 1, 10 and 100 μg/ml, b) linoleic acid: 0, 0.01, 0.1, 1, 10 and 100 μg/ml, c) linolenic acid: 0, 0.01, 0.1, 1, 10 and 100 μg/ml, d) oxytocin: 0, 10, 100, 1,000, 10,000 and 100,000 nm, e) tumor necrosis factor-α (TNF-α): 0, 0.05, 0.5, 1, 2.5 and 5 nm, f) progesterone: 0.1, 10, 25, 50, 75 and 100 nM, and g) estradiol: 0, 2.5, 5, 10, 20 and 50 nM. The control medium consisted of RPMI-1640 plus 10% bovine fetal serum. The growth of uterine epithelial were measured in terms of viability, cell number increment and monolayer formation. Results suggested that the growth of uterine epithelial cells were significantly (P < 0.05) higher in media containing 10 μg/ml, 10 μg/ml, 1 nm and 10 μg/ml linoleic acid, linolenic acid, TNF-α and LPS, respectively compared to control and lower doses used. Progesterone, estradiol and oxytocin did not significantly (P > 0.05) increase the growth of uterine epithelial cells. In conclusion, the growth of uterine epithelial cells increased when exposed to modulators in the order of linoleic acid ≥ linolenic acid ≥ LPS ≥ TNF-α > progesterone > estrogen > oxytocin.

Changes in luteal cells distribution, apoptotic rate, lipid peroxidation levels and antioxidant enzyme activities in buffalo (Bubalus bubalis) corpus luteum

Buffalo (Bubalus bubalis) is known for its weak/silent estrous behaviour, lower conception rate and longer inter-calving interval as compared to cattle. Understanding the kinetics and functional properties of luteal cells may be helpful to improve reproductive efficiency in the buffalo. Hence the present study was designed to assess the size and distribution of steroidogenic luteal cells along with biochemical properties during different phases of corpus luteum (CL) in the buffalo. The ovaries collected from the local abattoir were classified into three phases, early, mid and late, based on the morphological appearance of the CL as well as the follicles in the ovary. The proportion (%) of the luteal cells (>10microm diameter) increased (P<0.01) from early (30.7+/-1.3) to mid (36.30+/-1.6), and then decreased (P<0.01) in late luteal (31.46+/-1.8) phases. Percentage of small luteal cells (10-20microm diameter) was higher (P<0.05) in early (58.47+/-0.61) and mid (61.29+/-0.67) than late luteal (37.18+/-1.50) phases of CL. However, the percentage of large luteal cells (20-50microm diameter) was higher (P<0.05) only in late (62.82+/-1.50) than early (41.53+/-0.61) and mid (38.71+/-0.67) phases of CL. The average size (microm) of the large luteal cells increased (P<0.05) from early (25.46+/-0.62) to mid (27.15+/-0.5) and late (28.86+/-0.47) luteal phases. The percentage of luteal cells expressing in situ DNA fragmentation was significantly (P<0.05) higher in the late luteal (41.17+/-5.8) than mid-luteal (21.15+/-4.9) phase of the CL. In the early stage, half of the steroidogenic luteal cells had significantly (P<0.05) less 3beta-HSD activity than the other two phases. In the mid stage, the steroidogenic luteal cells had significantly higher (P<0.05) intense 3beta-HSD activity than the other two phases. Further in the late phase, a significant (P<0.05) reduction in intense 3beta-HSD activity was observed in the large luteal cells. The lipid peroxidation (micromol/g of CL) levels were significantly (P<0.05) higher in late luteal (3.46+/-0.2) than the mid-luteal (1.43+/-0.16) phases. The superoxide dismutase and catalase enzyme levels (U/mg of protein) were also significantly (P<0.05) higher in late luteal (0.9+/-0.015 and 3.37+/-0.45, respectively) than the mid-luteal (0.1+/-0.01 and 2.34+/-0.3, respectively) phases. In contrast, the GPx activity (U/mg of protein) decreased significantly (P<0.05) from mid-luteal (1.85+/-0.4) to late luteal (1.22+/-0.2) phases. The present study suggests that (i) the decrease in progesterone levels in late CL may be associated with loss of 3beta-HSD activity in large luteal cells and (ii) demise of the buffalo CL may be mediated by apoptosis despite the high levels of luteal antioxidant enzymes.

Effect of suppression of plasma prolactin on luteinizing hormone concentration, intersequence pause days and egg production in domestic hen

The aim of this study was to investigate the effects of suppression of plasma prolactin (PRL) concentration on circulating concentrations of luteinizing hormone (LH), progesterone (P(4)), estradiol (E(2)beta), pause days and egg production in birds later in the reproductive period. Twenty-four White Leghorn birds of same age group were divided into two groups of 12 in each. Birds of each group were administered s/c either with placebo (control group) or equal volumes of anti PRL agent (2-bromo-alpha-ergocriptine) solution containing at 100 microg/kg body weight/hen/week (treated group) from 72 to 82 weeks of age. Egg production and inter sequence pauses were recorded daily from both the groups. Plasma PRL, LH, E(2)beta and P(4) concentrations were estimated in blood samples collected at weekly intervals. At 77th weeks of age, blood samples from treated and control birds were obtained every 3h for 36h to study the surges of LH. It was found that plasma PRL concentration was lower (p<0.01) in bromocriptine treated birds with high concentrations of LH, its 3h LH surges, E(2)beta and P(4) in plasma. Higher egg production, less pause days in treated birds may be the result of low PRL concentration, associated with positively correlated responses of high concentrations of LH (with regular interval and duration of LH surges), E(2)beta and P(4) concentration required for completion of egg formation and oviposition. In conclusion, bromocriptine administration decreased (p<0.01) PRL concentration increased (p<0.01) steroid hormones and LH surges, for egg formation and oviposition and enabled the birds to lay more eggs even later in the productive period with the available resources under normal husbandry practices.

The possible role of prolactin in laying performance and steroid hormone secretion in domestic hen (Gallus domesticus)

The aim of this study was to investigate the basic physiological mechanism involved in taking pauses between the sequences of egg laying in domestic hen to improve egg production by extending the sequence length and decreasing the intersequence pause days by modulating the prolactin concentration in birds. Fifty healthy female white leghorn birds were administered anti-prolactin agent (2-bromo-alpha-ergocriptine, Sigma, USA) subcutaneously at 100 microg/kg body weight at weekly intervals from 17th to 36th week of age. Another group of fifty birds was given placebo in place of the modulating agent. The level of prolactin remained lower in the treated birds than in the control birds throughout the production cycle up to 72 weeks of age. The level of prolactin in the control group was found to decrease during the peak production period. The average percentage of egg production from 19 to 72 week period was 87.67 in the treatment group as compared to 83.56 in the control group. Oestradiol-17beta and progesterone concentrations in the treated birds were significantly (P<0.01) higher than those in control birds, during and after withdrawal of the treatment. Prolactin level was negatively correlated with egg production (r=-0.02; r=-0.12) and with oestradiol-17beta (r=-0.75; r=-0.38) and progesterone (r=-0.20; r=-0.83), respectively, in control and treatment groups. The total number of pause days during the production period decreased significantly (P<0.01) in the treatment group, resulting in a 4.11% increase in egg production. It is concluded that there is a consistent relationship between plasma prolactin in the physiological range and laying performance in domestic hen.