A Role for Adrenergic Receptors in the Uterotonic Effects of Ergometrine in Isolated Human Term Nonlaboring Myometrium

Effect of blocking of alpha1-adrenoreceptor isoforms on the noradrenaline-induced changes in contractility of inflamed pig uterus

BACKGROUND

Disturbances in uterine contractility often lead to the origin, development and maintenance of endometritis and metritis, which are a very common and serious pathologies in domestic animals. Here we aimed to investigate the role of α1A-, α1B- and α1D-adrenoreceptors (ARs) in noradrenaline (NA)-induced contractility of inflammatory-changed porcine uterus.

METHODS

On Day 3 of the estrous cycle, either Escherichia coli (E. coli) suspension (E. coli group) or saline (SAL group) was injected into uterine horns, or only laparotomy was performed (CON group). Eight days later, infected gilts developed severe acute endometritis.

RESULTS

Compared to the period before NA application, NA reduced the contractile amplitude and frequency in myometrium (MYO) and endometrium (ENDO)/MYO strips from the CON, SAL and E. coli groups. In the last group, the amplitude in MYO and the frequency in ENDO/MYO were lowered versus other groups. After using α1A-ARs antagonist with NA, a greater decrease or occurrence of a drop in the amplitude and frequency in all groups (ENDO/MYO) were found compared to this neurotransmitter action alone. Such results were noted for NA action on the frequency after α1B-ARs blocking in the CON (both kinds of strips) and SAL (ENDO/MYO) groups. In response to α1D-ARs antagonist with NA, a greater decrease or occurrence of a drop in the amplitude was noted in the CON (both kinds of strips) and SAL and E. coli (MYO) groups. Use of these factors caused the similar changes in the frequency in CON and E. coli (MYO) and SAL (ENDO/MYO) groups. In response to NA, α1A,B,D-ARs antagonist led to a greater reduction or appearance of a drop in the amplitude in the CON and SAL (ENDO/MYO) and E. coli (both kinds of strips) as well as in the frequency in the CON and SAL (ENDO/MYO) and E. coli (MYO) groups.

CONCLUSIONS

In conclusion, activation of α1A- and α1D-ARs by NA promotes the contractile amplitude and frequency in the inflamed pig uterus; pharmacological modulation of these receptors can be utilized to enhance systolic activity of myometrium.

Naturally derived indole alkaloids targeting regulated cell death (RCD) for cancer therapy: from molecular mechanisms to potential therapeutic targets

Regulated cell death (RCD) is a critical and active process that is controlled by specific signal transduction pathways and can be regulated by genetic signals or drug interventions. Meanwhile, RCD is closely related to the occurrence and therapy of multiple human cancers. Generally, RCD subroutines are the key signals of tumorigenesis, which are contributed to our better understanding of cancer pathogenesis and therapeutics. Indole alkaloids derived from natural sources are well defined for their outstanding biological and pharmacological properties, like vincristine, vinblastine, staurosporine, indirubin, and 3,3′-diindolylmethane, which are currently used in the clinic or under clinical assessment. Moreover, such compounds play a significant role in discovering novel anticancer agents. Thus, here we systemically summarized recent advances in indole alkaloids as anticancer agents by targeting different RCD subroutines, including the classical apoptosis and autophagic cell death signaling pathways as well as the crucial signaling pathways of other RCD subroutines, such as ferroptosis, mitotic catastrophe, necroptosis, and anoikis, in cancer. Moreover, we further discussed the cross talk between different RCD subroutines mediated by indole alkaloids and the combined strategies of multiple agents (e.g., 3,10-dibromofascaplysin combined with olaparib) to exhibit therapeutic potential against various cancers by regulating RCD subroutines. In short, the information provided in this review on the regulation of cell death by indole alkaloids against different targets is expected to be beneficial for the design of novel molecules with greater targeting and biological properties, thereby facilitating the development of new strategies for cancer therapy.

Lippia origanoides essential oil induces tocolytic effect in virgin rat uterus and inhibits writhing in a dysmenorrhea mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

The species Lippia origanoides Kunth, popularly known as "salva-de-marajó", is used in Brazilian traditional "quilombola" communities to treat menstrual cramps and uterine inflammation.

AIM OF THE STUDY

Evaluate the spasmolytic activity of Lippia origanoides essential oil (LOO) on experimental models of uterine conditions related to menstrual cramps and investigate its mechanism of action.

MATERIALS AND METHODS

Virgin rat-isolated uterus was mounted in the organ bath apparatus to evaluate the spasmolytic effect of LOO on basal tonus and contractions induced by carbachol, KCl, or oxytocin. We used pharmacological agents to verify the relaxation mechanism of LOO. The evaluation of uterine contractility in virgin rats, after treatment with LOO for three consecutive days, was carried out by the construction of a concentration-response curve with oxytocin or carbachol. The primary dysmenorrhea animal model was replicated with an injection of estradiol cypionate in female mice for three consecutive days, followed by intraperitoneal application of oxytocin.

RESULTS

LOO relaxed the rat uterus precontracted with 10^-2 IU/mL oxytocin (logEC₅₀ = 1.98 ± 0.07), 1 μM carbachol (logEC₅₀ = 1.42 ± 0.07) or 60 mM KCl (logEC₅₀ = 1.53 ± 0.05). It was also able relax uterus on spontaneous contractions (logEC₅₀ = 0.41 ± 0.05). Preincubation with glibenclamide, propranolol, phentolamine or L-NAME in contractions induced by carbachol did not alter significantly the relaxing effect of LOO. However, in the presence of 4-aminopyridine, CsCl or tetraethylammonium there was a reduction of LOO potency, whereas the blockers methylene blue, ODQ, aminophylline and heparin potentiated the LOO relaxing effect. Preincubation with LOO in a Ca²⁺ free medium at concentrations of 27 μg/mL or 81 μg/mL reduced the contraction induced by carbachol. The administration of LOO for 3 days did not alter uterus contractility. The treatment with LOO at 30 or 100 mg/kg intraperitoneally, or 100 mg/kg orally, inhibited writhing in female mice. The association of LOO at 10 mg/kg with nifedipine or mefenamic acid potentiated writhing inhibition in mice.

CONCLUSIONS

The essential oil of L. origanoides has tocolytic activity in rat isolated uterus pre-contracted with KCl, oxytocin, or carbachol. This effect is possibly related to the opening of potassium channels (K_ir, K_V, and K_Ca), cAMP increase, and diminution of intracellular Ca²⁺. This relaxant effect, probably, contributed to reduce the number of writhings in an animal model of dysmenorrhea being potentiated by nifedipine or mefenamic acid. Taken together, the results here presented indicate that this species has a pharmacological potential for the treatment of primary dysmenorrhea, supporting its use in folk medicine.

Refractory uterine atony: still a problem after all these years

Postpartum hemorrhage is a leading cause of maternal morbidity and mortality, and uterine atony is the leading cause of postpartum hemorrhage. Risk factors for uterine atony include induced or augmented labor, preeclampsia, chorio-amnionitis, obesity, multiple gestation, polyhydramnios, and prolonged second stage of labor. Although a risk assessment is recommended for all parturients, many women with uterine atony do not have risk factors, making uterine atony difficult to predict. Oxytocin is the first-line drug for prevention and treatment of uterine atony. It is a routine component of the active management of the third stage of labor. An oxytocin bolus dose as low as 1 IU is sufficient to produce satisfactory uterine tone in almost all women undergoing elective cesarean delivery. However, a higher bolus dose (3 IU) or infusion rate is recommended for women undergoing intrapartum cesarean delivery. Carbetocin, available in many countries, is a synthetic oxytocin analog with a longer duration than oxytocin that allows bolus administration without an infusion. Second line uterotonic agents include ergot alkaloids (ergometrine and methylergonovine) and the prostaglandins, carboprost and misoprostol. These drugs work by a different mechanism to oxytocin and should be administered early for uterine atony refractory to oxytocin. Rigorous studies are lacking, but methylergonovine and carboprost are likely superior to misoprostol. Currently, the choice of second-line agent should be based on their adverse effect profile and patient comorbidities. Surgical and radiologic management of uterine atony includes uterine tamponade using balloon catheters and compression sutures, and percutaneous transcatheter arterial embolization.

Identification and validation of key miRNAs and miRNA-mRNA regulatory network associated with uterine involution in postpartum Kazakh sheep

MicroRNAs (miRNAs) are widely expressed in different mammalian tissues and exert their biological effects through corresponding target genes. miRNA target genes can be rapidly and efficiently identified and screened by combining bioinformatics prediction and experimental validation. To investigate the possible molecular regulatory mechanisms involving miRNAs during uterine involution in postpartum ewes, we used Illumina HiSeq sequencing technology to screen for the number and characteristics of miRNAs in faster uterine involution and normal uterine involution group. A total of 118 differentially expressed miRNAs, including 33 known miRNAs and 85 new miRNAs, were identified in the hypothalamic library, whereas 54 miRNAs, including 5 known miRNAs and 49 new miRNAs, were identified in the uterine library. Screening with four types of gene prediction software revealed 73 target genes associated with uterine involution, and subsequently, GO annotation and KEGG pathway analysis were performed. The results showed that, in the hypothalamic–uterine axis, uterine involution in postpartum ewes might primarily involve two miRNA-target gene pairs, namely, miRNA-200a–PTEN and miRNA-133–FGFR1, which can participate in GnRH signal transduction in the upstream hypothalamus and in the remodeling process at the downstream uterus, through the PI3K–AKT signaling pathway to influence the recovery of the morphology and functions of the uterus during the postpartum period in sheep. Therefore, identification of differentially expressed miRNAs in this study fills a gap in the research related to miRNAs in uterine involution in postpartum ewes and provides an important reference point for a comprehensive understanding of the molecular mechanisms underlying the regulation of postpartum uterine involution in female livestock.

Co-Occurrence and Combinatory Effects of Alternaria Mycotoxins and other Xenobiotics of Food Origin: Current Scenario and Future Perspectives

Mycotoxins are low-molecular weight compounds produced by diverse genera of molds that may contaminate food and feed threatening the health of humans and animals. Recent findings underline the importance of studying the combined occurrence of multiple mycotoxins and the relevance of assessing the toxicity their simultaneous exposure may cause in living organisms. In this context, for the first time, this work has critically reviewed the most relevant data concerning the occurrence and toxicity of mycotoxins produced by Alternaria spp., which are among the most important emerging risks to be assessed in food safety, alone or in combination with other mycotoxins and bioactive food constituents. According to the literature covered, multiple Alternaria mycotoxins may often occur simultaneously in contaminated food, along with several other mycotoxins and food bioactives inherently present in the studied matrices. Although the toxicity of combinations naturally found in food has been rarely assessed experimentally, the data collected so far, clearly point out that chemical mixtures may differ in their toxicity compared to the effect of toxins tested individually. The data presented here may provide a solid foothold to better support the risk assessment of Alternaria mycotoxins highlighting the actual role of chemical mixtures on influencing their toxicity.

A comparison of the effects of lindane and FeCl3/ADP on spontaneous contractions in isolated rat or human term myometrium

Oxidative stress affects the contractile behavior of smooth muscle resulting in complications during labor. Toxicants such as lindane and ferric chloride (FeCl₃)/adenosine diphosphate (ADP) cause oxidative stress and have previously been shown to inhibit smooth muscle contraction. In this study we examined the effects of the oxygen species scavengers, ascorbic acid and N-acetylcysteine on lindane and FeCl₃/ADP's inhibition of spontaneous myometrial contractions in rat and human myometrium. Lindane and FeCl₃/ADP gave rise to concentration-dependent reductions in rat (EC₅₀ 11.8×10^-6M and 0.9×10^-3M) and human myometrial contractions (EC₅₀ 16.3×10^-6M and 1.1×10^-3M, respectively). Pre-treatment with N-acetylcysteine significantly increased the EC₅₀ for the effects of lindane on motility index of human tissue and reduced the maximum inhibitory effect of FeCl₃/ADP on contractions in both rat and human myometrium. Ascorbic acid reduced the effects of FeCl₃/ADP in rat tissue only. In conclusion pre-treatment with specific antioxidants may protect both rat and human myometrium from the inhibitory effects of lindane and FeCl₃/ADP.