Effects of oxytocin and PGF2α on uterine contractility in cows with and without metritis-An in-vitro study

Effect of oxytocin added into sperm on artificial insemination in sheep

Abstract. The use of additional oxytocin hormones in reproductive methods began in the 1970s in Europe. In recent studies, attempts have been made to achieve more successful pregnancies by adding oxytocin to semen rather than administering oxytocin exogenously to females. In light of this information, this study aimed to understand the effects of adding low-dose oxytocin hormone into ram semen on the pregnancy rate and reproductive efficiency of sheep. Semen was collected from five Chios rams. The ejaculates were pooled and Ovixcell® was used as the diluent. The estrus was synchronized using an intravaginal sponge (Chrono-Gest®) from 122 Chios ewes. After the sponge was left in the vagina for 12 d, a 500 IU PMSG injection was made. In every sheep, intramuscular (IM) injections were inseminated by the intracervical method using an insemination gun 50 h after injection. Pregnancy results were obtained by ultrasound examination without practice. Lambing performance was recorded at delivery; 53 out of 122 Chios ewes were inseminated with oxytocin hormone content, and successful pregnancy was achieved in 90.56 % of them. In the insemination of the remaining 69 sheep, oxytocin was not added, and the rate of successful pregnancy was 76.81 % (p=0.046). The overall success rate based on the insemination results of all the sheep was determined to be 82.77 %. In an examination of the pregnancy rate, one of the indicators of reproductive performance, the difference between the groups is statistically significant (p≤0.05). Higher pregnancies were obtained in insemination with semen fluid containing oxytocin.

Involvement of the calcitonin gene-related peptide system in the modulation of inflamed uterus contractile function in pigs

This study analyzed severe acute endometritis action on myometrial density and distribution of protein gene product (PGP)9.5- and calcitonin gene-related peptide (CGRP)-like immunoreactive nerve fibers and calcitonin receptor-like receptor (CLR) expression, and on CGRP receptor (CGRPR) participation in uterine contractility in pigs. E. coli suspension (E. coli group) or saline (SAL group) were injected into the uteri, or only laparotomy was performed (CON group). In the E. coli group myometrium, a lack of significant changes in PGP9.5 and CGRP innervation patterns and increased CLR protein level were revealed. In all groups, compared to the pretreatment period, human αCGRP increased amplitude in the myometrium, while reducing it in endometrium/myometrium. In the E. coli group endometrium/myometrium, human αCGRP lowered amplitude vs other groups. Human αCGRP reduced frequency in CON and SAL groups and enhanced it in the E. coli group endometrium/myometrium. The frequency in E. coli group increased vs other groups. CGRPR antagonist, human αCGRP8-37, reversed (CON, SAL groups) and eliminated (E. coli group) the rise in human αCGRP-induced myometrial amplitude. In endometrium/myometrium, human αCGRP8-37 abolished (CON group) and reversed (SAL group) a decrease in frequency, and reduced the rise in frequency (E. coli group) caused by human αCGRP. Collectively, in the myometrium, endometritis did not change PGP9.5 and CGRP innervation patterns and enhanced CLR protein level. CGRPR also mediated in CGRP action on inflamed uterus contractility.

Clostridium butyricum and Its Culture Supernatant Alleviate the Escherichia coli-Induced Endometritis in Mice

Endometritis is a disease with a high incidence in dairy cows and causes great economic loss to milk production. This study examined the therapeutic effects of Clostridium butyricum and its culture supernatant on Escherichia coli-induced endometritis in mice. The results showed that Clostridium butyricum and its culture supernatant effectively suppressed inflammatory responses of uterine tissues, such as uterine morphological changes, pathological damage, and the production of inflammatory cytokines. Clostridium butyricum and its culture supernatant significantly decreased uterine microbial loads. In addition, Clostridium butyricum and its culture supernatant restored reproduction outcomes in Escherichia coli-induced endometritis mice. Western blot analysis showed that Clostridium butyricum and its culture supernatant suppressed the NF-κB signaling pathway. Therefore, the anti-inflammatory mechanism of Clostridium butyricum and its culture supernatant may occur through the anti-bacterial activity and regulation of the expression of NF-κB in the uterus. The anti-inflammatory effect of the culture supernatant of C. butyricum was slightly better than that of viable C. butyricum. Therefore, our experimental results showed that Clostridium butyricum culture supernatant may be an effective drug for treating endometritis.

Prolonging the time of semen deposition increases the pregnancy rates of ewes subjected to fixed time cervical insemination during the breeding season

The main limiting factor of artificial cervical insemination in ewes is the long and narrow fibrous cervical canal, which impedes the transport of spermatozoa and leads to lower pregnancy rates. The hypothesis that prolonging the time of semen deposition during ovine cervical insemination can increase pregnancy rates was investigated in this study. Estrus was synchronized in 150 multiparous Ujimqin ewes using a polyurethane intravaginal sponge impregnated with 45 mg of flurogestone acetate. The sponge was left in the vagina for 12 days followed by an injection of 330 IU of eCG at sponge removal. After exclusion of two ewes due to sponge loss, the remaining 148 ewes were divided into the Treatment group (n = 75) and the Control group (n = 73). Each ewe was inseminated once between 56 h to 60 h after the removal of sponges, using a new type of insemination device containing 0.25 ml of diluted semen. Semen was collected from eight Black Suffolk rams and all the ejaculates were pooled and diluted in ultra-high temperature-treated commercial skimmed milk. The time of semen deposition was prolonged to 60 s in the Treatment group, while ewes were given a traditional insemination in the Control group. Pregnancy status was determined by transabdominal ultrasound examination 45 days after insemination. Lambing performance was calculated after all the ewes had delivered. Significant differences were observed between the Treatment group and the Control group in terms of the pregnancy rate and the fecundity rate (73.3% and 93.3% vs 56.2% and 71.2%, p < 0.05 and p < 0.01, respectively). In conclusion, prolonging the time of semen deposition significantly increased pregnancy and fecundity rates in estrus-synchronized Ujimqin ewes subjected to fixed time cervical insemination.

Investigation of the Role of Pituitary Adenylate Cyclase-Activating Peptide (PACAP) and Its Type 1 (PAC1) Receptor in Uterine Contractility during Endometritis in Pigs

Uterine inflammation is a common pathology in animals, leading to disturbances in reproductive processes and reduced production profitability. Pituitary adenylate cyclase-activating peptide (PACAP) effects at the uterine level during inflammation are not known. In the current study, we analyzed the relative PACAP type 1 receptor (PAC1R) mRNA transcript and protein abundances in the myometrium (MYO), as well s PACAP and PAC1R involvement in the contractile function of inflamed pig uterus. To that end, E. coli suspension (E. coli group) or saline (SAL group) was injected into the uterine horns or laparotomy was performed (CON group). Eight days after the bacteria injections, severe acute endometritis and a reduced relative abundance of PAC1R protein in the MYO were observed. Compared to the period before PACAP in vitro administration, PACAP (10^-7 M) in the CON and SAL groups decreased in amplitude in the MYO and endometrium (ENDO)/MYO, whereas in the E. coli group, increased amplitude in the MYO and reduced amplitude in the ENDO/MYO were observed. In the E. coli group, PACAP enhanced the amplitude in the MYO (10^-7 M) and decreased the amplitude in the ENDO/MYO (10^-8 M) compared with other groups. PACAP (10^-7 M) increased the frequency of both kinds of strips in the CON and SAL groups compared with the pretreatment period. PACAP (both doses) did not significantly change the frequency in the E. coli group, whereas in response to PACAP (10^-7 M), the frequency was reduced compared to other groups. In the MYO, PAC1R antagonist decreased the amplitude reduction (CON and SAL groups) and reversed a rise in PACAP (10^-7 M)-evoked amplitude (E. coli group). PAC1R blocking reversed (MYO) and abolished (ENDO/MYO) the stimulatory effect of PACAP (10^-7 M) on the frequency (CON and SAL groups). PAC1R antagonist and PACAP (10^-7 M) evoked the appearance of frequency depression in both kinds of strips (E. coli group). In summary, in pigs, severe acute endometritis reduces the relative abundance of PAC1R protein in the MYO, and PAC1R mediates the influence of PACAP on inflamed uterus contractility.

Effect of metritis on in-vitro uterine contractility in cows during the puerperium

Aim of this study was to determine the effect of metritis on in-vitro uterine contractility. Uteri obtained from 16 euthanized Holstein-Friesian cows were divided into two groups depending on whether metritis was absent (M-, n = 6) or present (M+, n = 10). Four longitudinal and four circular myometrial strips of all uteri were incubated in an organ bath. Spontaneous contractility was recorded in five consecutive 30-minute periods (T1-T5). This was followed by stimulation of one longitudinal and one circular strip with increasing concentrations of oxytocin, prostaglandinF_2α (PGF_2α), and calcium chloride (each during four 30-minute periods [T6-T9]). Strips in group M+ had higher minimum amplitude (minA) values at T1 and higher minA, mean amplitude (meanA), and area under the curve (AUC) values at T2 than strips in group M- (P ≤ 0.05). In the M+ group, the maximum amplitude (maxA), meanA, and AUC values of circular strips were higher than those of longitudinal strips during spontaneous contractility (T1, T4, and T5; P ≤ 0.05). The minA, meanA, and AUC values for strips in group M+ were higher than those in group M- when exposed to the highest concentration of PGF_2α (P ≤ 0.05). During stimulation with PGF_2α (T9), longitudinal strips had higher maxA values than the circular strips in group M+ (P ≤ 0.05). Spontaneous and stimulated contractility were temporarily increased in uteri with metritis compared to healthy uteri. Both myometrial layers, especially in uteri with metritis, reacted differently during spontaneous contractility and to stimulation with PGF_2α.

Regulatory Influence of Galanin and GALR1/GALR2 Receptors on Inflamed Uterus Contractility in Pigs

Uterine inflammation is a very common and serious pathology in domestic animals, the development and progression of which often result from disturbed myometrial contractility. We investigated the effect of inflammation on the protein expression of galanin (GAL) receptor subtypes (GALR)1 and GALR2 in myometrium and their role in the contractile amplitude and frequency of an inflamed gilt uterus. The gilts of the E. coli and SAL groups received E. coli suspension or saline in their uteri, respectively, and only laparotomy was performed (CON group). Eight days later, the E. coli group developed severe acute endometritis and lowered GALR1 protein expression in the myometrium. Compared to the pretreatment period, GAL (10⁻⁷ M) reduced the amplitude and frequency in myometrium and endometrium/myometrium of the CON and SAL groups, the amplitude in both stripes and frequency in endometrium/myometrium of the E. coli group. In this group, myometrial frequency after using GAL increased, and it was higher than in other groups. GALR2 antagonist diminished the decrease in amplitude in myometrium and the frequency in endometrium/myometrium (SAL, E. coli groups) induced by GAL (10⁻⁷ M). GALR1/GALR2 antagonist and GAL (10⁻⁷ M) reversed the decrease in amplitude and diminished the decrease in frequency in both examined stripes (CON, SAL groups), and diminished the drop in amplitude and abolished the rise in the frequency in the myometrium (E. coli group). In summary, the inflammation reduced GALR1 protein expression in pig myometrium, and GALR1 and GALR2 participated in the contractile regulation of an inflamed uterus.

Oxytocin increases pregnancy rates after fixed time artificial insemination in Kazak ewes

It is probable that reduced pregnancy rates in ewes after fixed time artificial insemination (FTAI) is attributable, in part, to the reduced number of normal spermatozoa that colonize the oviduct. Administration of oxytocin stimulates both cervical dilation and uterine/oviductal contractility. The hypothesis that oxytocin can enhance sperm transport into the uteri and the oviducts, and thereby increase pregnancy rates, was tested in the present study. Oestrus was synchronized in 199 multiparous Kazak ewes using intravaginal flurogestone-impregnated sponge. The sponge was left in the vagina for 12 days followed with an injection of 330 IU of eCG at sponge removal. Each ewe was intracervically inseminated twice at 50 hr and 62 hr after the removal of sponges using an insemination catheter containing 0.25 ml of diluted semen. Semen was collected from seven Texel rams and all the ejaculates were pooled and diluted in ultra-high temperature-treated commercial skimmed milk without (Control group, 0.05 ml of saline per mL milk, n = 144) or with oxytocin supplement (Oxytocin group, 0.5 U of oxytocin per ml milk, n = 55). Pregnancy status was determined by transabdominal ultrasound examination 45 days after insemination. Lambing performance was recorded at delivery. Significant differences were observed between the Oxytocin group and the Control group in terms of the pregnancy rate and the fecundity rate (85.5% and 92.7% versus 68.8% and 72.9%, respectively). In conclusion, low dose oxytocin supplementation of semen extender significantly increased pregnancy and fecundity rates in oestrus-synchronized Kazak ewes after FTAI.

In vitro effects of citral on the human myometrium: Potential adjunct therapy to prevent preterm births

BACKGROUND

Premature infants contribute to infant morbidity and mortality especially in low resource settings. Information on tocolytic and/or anti-inflammatory effects of several plant extracts, such as citral, could help prevent preterm birth cases and reduce the number of preterm infants. The aim of this study was to evaluate the in vitro tocolytic and anti-inflammatory effect of citral on myometrial tissues of the human uterus.

METHODS

Myometrial samples from uteri obtained after hysterectomy were used in functional tests to evaluate the inhibitory effect of citral on PGF-2α induced contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to citral in human myometrial homogenates were measured by ELISAs. Forskolin was used as a positive control. The anti-inflammatory effect of citral was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and the anti-inflammatory cytokine IL-10, in human myometrial explants stimulated with lipopolysaccharide (LPS).

RESULTS

Citral was able to induce a significant inhibition of PGF-2α induced contractions at the highest concentration level (p < .05). Citral caused a concentration-dependent increase in myometrial cAMP levels (p < .05) and a concentration-dependent decrease in LPS-induced TNFα and IL-1β production, while IL-10 production increased significantly (p < .05). The anti-inflammatory and tocolytic effects induced by citral could be associated with an increase in cAMP levels in human myometrial samples.

CONCLUSION

These properties place citral as a potentially safe and effective adjuvant agent in preterm birth cases, an obstetric and gynecological problem that requires urgent attention.

The role of somatostatin and its receptors (sstr2, sstr5) in the contractility of gilt inflamed uterus

We studied the inflammation effect on somatostatin receptors subtypes 2 (sstr2) and 5 (sstr5) expression in myometrium and somatostatin influence alone or with sstr2 and sstr5 antagonists on the contractility of gilt inflamed uterus. On day 3 of the estrous cycle, either E.coli suspension (E.coli group) or saline (SAL group) were injected into uterine horns. In the control pigs (CON group), only laparotomy was performed. Eight days later, in the E.coli group developed severe acute endometritis. In this group, myometrial sstr2 mRNA expression lowered and protein expression increased compared to other groups. Compared to period before somatostatin administration, somatostatin did not change tension in myometrium and endometrium/myometrium of three groups, reduced amplitude and frequency in the CON and SAL groups, and increased amplitude and decreased frequency in the E.coli group. In this group, amplitude was increased by somatostatin compared to other groups. In the CON and SAL groups, sstr2 eliminated inhibitory somatostatin effect on amplitude, while sstr5 antagonist reversed inhibitory somatostatin effect on amplitude. In the E.coli group, sstr2 antagonist reversed stimulatory somatostatin effect on amplitude, while in sstr5 antagonist presence stimulatory somatostatin effect was more deepened compared to somatostatin action alone. After using sstr2 antagonist more deepened inhibitory somatostatin effect on frequency in the CON and E.coli groups was found. Sstr5 antagonist partly eliminated inhibitory somatostatin effect on frequency in the SAL group. Summarizing, the uterine inflammation increases the myometrial sstr2 protein expression; somatostatin raises amplitude of the inflamed uterus acting by sstr2, while drops this parameter by sstr5.

Inflammation changes the expression of neuropeptide Y receptors in the pig myometrium and their role in the uterine contractility

In the experiment the influence of inflammation on neuropeptide Y (NPY) receptor subtype 1 (Y1Rs) and 2 (Y2Rs) expression pattern in the gilt myometrium and NPY effect alone or with Y1Rs and Y2Rs antagonists on contractility of an inflamed uterus were recognized. On Day 3 of the estrous cycle, either E.coli suspension (E.coli group) or saline (SAL group) were administered into uterine horns. In the control gilts (CON group), only laparotomy was carried out. Eight days later, E.coli treatment evoked severe acute endometritis, significantly reduced Y1Rs mRNA and protein expression and increased Y2Rs protein expression in myometrium in relation to the CON and SAL groups. Compared to period before NPY application, NPY (10⁻⁷ M) significantly reduced amplitude in myometrium and endometrium/myometrium and frequency in myometrium of the CON and SAL groups and amplitude in endometrium/myometrium and frequency in strips of the E.coli group. In this group, after using NPY (10⁻⁷ M), the amplitude rose significantly in both kinds of strips, while frequency fell in endometrium/myometrium in relation to the SAL group. In the CON and SAL groups, NPY (10⁻⁷ M) with Y1Rs antagonist significantly increased the amplitude in endometrium/myometrium, while with Y2Rs antagonist caused a rise in myometrium. In the E.coli group after using Y1Rs or Y2Rs antagonist and NPY (10⁻⁷ M) amplitude did not significantly change in endometrium/myometrium, and this parameter was significantly lower after using the NPY and Y1Rs antagonist than in other groups. Y1Rs antagonist and NPY (10⁻⁸, 10⁻⁷ M) significantly increased frequency in endometrium/myometrium of the CON and SAL groups. In the E.coli group, Y1Rs or Y2Rs antagonists and NPY (10⁻⁷ M) significantly increased frequency in myometrium and it was significantly higher than in the CON group. Inflammation changes Y1Rs and Y2Rs expression in myometrium of the inflamed pig uterus and NPY reduces this organ contractility by Y1Rs and Y2Rs.

Variability of serum reproductive hormones in cows presenting various reproductive conditions in semi-arid areas of the North West Province, South Africa

Background and Aim:

Hormones play a significant role in supporting reproductive processes. Predisposition to metabolic disorders may result from biological alterations in the neurohormonal system, thus leading to impaired immune function and poor reproductive performance. The aim of this study was to determine the reproductive hormonal profile in cows with reproductive conditions in semi-arid areas of the North West Province, South Africa, to establish possible correlations between different conditions and the hormonal profile.

Materials and Methods:

Blood samples were collected from cows in different communal areas of Mafikeng. Convenience sampling was used to collect samples for the study. Blood samples were collected cows experiencing dystocia (n=50), retained placenta (n=13), downer cow syndrome (n=34), vaginal prolapse (n=16), and abortions (n=69), following cases reported at the Animal Health Hospital of the North-West University, Mafikeng Campus. Descriptive statistics, such as mean and standard deviations, were used to describe the distribution of hormone levels across reproductive conditions. p-value less than the significance level was set at 5% (p<0.05).

Results:

Data obtained revealed significantly higher estradiol in abortion (1122.99±71.99 pg/ml), downer cow syndrome (781.32±135.7 pg/ml), and dystocia (862.09±123.44 pg/ml). Oxytocin (OT) differed significantly in cows with dystocia (370.50±71.66 pg/ml) and abortion (574.73±60.65 pg/ml). Significantly low progesterone (Pg) was observed in abortion (2.45±1.509 ng/ml) and dystocia (8.59±0.402 ng/ml) while increased prostaglandin alpha was observed in cows with vaginal prolapse and abortion.

Conclusion:

The findings highlight an increase in serum estradiol and OT in aborting cows. Low Pg and estradiol in cows with vaginal prolapses and retained placenta were noted. An association was seen between downer cow syndrome and high concentrations of estradiol and Pg. Prostaglandin alpha may increase in cases of vaginal prolapse and abortion. Hormonal alterations were observed and may contribute to the incidences of different reproductive conditions.

Participation of acetylcholine and its receptors in the contractility of inflamed porcine uterus

This study analyzed the effect of inflammation on acetylcholine (ACh)-induced muscarinic receptors (MR)2 and MR3 conducted contractility of the porcine uterus. On Day 3 of the estrous cycle, either E.coli suspension (E.coli group) or saline (SAL group) was injected into uterine horns or laparotomy was performed (CON group). Eight days later, infected gilts developed severe acute endometritis. Compared to the period before ACh treatment, ACh (10^-5 M) increased the tension in myometrium (MYO) and endometrium/myometrium (ENDO/MYO) of the CON group (P < 0.01) and in ENDO/MYO of the SAL group (P < 0.01), the amplitude in strips of the CON (P < 0.05) and SAL (MYO: P < 0.05, ENDO/MYO: P < 0.001) groups and the frequency in strips of the CON (MYO: P < 0.01, ENDO/MYO: P < 0.001) and SAL (P < 0.01) groups. In the E.coli group, ACh (10^-5 M) reduced the amplitude in MYO (P < 0.05) and ENDO/MYO (P < 0.001), increased the frequency in MYO (P < 0.01) and ENDO/MYO (P < 0.001) and did not change (P > 0.05) the tension. ACh (10^-5 M) in ENDO/MYO of the E.coli group, reduced the tension compared to the CON group (P < 0.05) and the amplitude compared to other groups (P < 0.001), while increased the frequency in relation to the SAL group (P < 0.05). MR2 antagonist (AF-DX 44 116) and ACh (10^-5 M) reduced (by 16.92%, P < 0.01) the tension in MYO of the CON group and increased (P < 0.01) it in the E.coli group compared to the period before antagonist and ACh addition. In MYO of the SAL group, the tension was increased (P < 0.01) in response to MR3 antagonist (4-DAMP) and ACh (10^-7, 10^-6 M). In the E.coli group, these substances did not change (P > 0.05) the tension, but it was lower (P < 0.001) in MYO (ACh: 10^-7 M) and ENDO/MYO (ACh: 10^-5 M) than in the SAL group. MR2 or MR3 antagonists and ACh (10^-5 M) increased (P < 0.05-0.001) the amplitude in strips of the CON and SAL groups and reduced it in the E.coli group (P < 0.001) compared to the period before antagonists and ACh use. This parameter in the E.coli group was lower (P < 0.001) after using MR2 or MR3 antagonists and ACh (10^-6, 10^-5 M) than in other groups. Both antagonists and ACh (10^-5 M) reduced the frequency in the CON, SAL (P < 0.05) and E.coli (MR2 antagonist: P < 0.01, MR3 antagonist: P < 0.05) groups compared to period before antagonists and ACh addition. Data show that ACh reduces the contractility of the inflamed porcine uterus by MR2 and MR3, which suggests that pharmacological modulation of these receptors can be used to raise the contractility of an inflamed uterus.