Contraction Of Uterine Smooth Muscle Research Articles

Role of CPI-17 on uterine smooth muscle contraction depending on pregnancy stage

Role of CPI-17 on uterine smooth muscle contraction depending on pregnancy stage

ІОННІ КАНАЛИ В КОНТЕКСТІ ПОШУКУ МОЛЕКУЛЯРНИХ МІШЕНЕЙ РЕГУЛЯЦІЇ СКОРОТЛИВОСТІ МІОМЕТРІЮ

Many women now have complications in childbirth due to poor labor, which often threatens both mother and fetus. Also,the problem of prevention and treatment of premature uterine contractions is unresolved. Therefore, in this work we investigated the influence of ion channels as the end stage effectors of the regulatory cascades in the contractility of myometrium. To better understand the participation of TRPC4, TRPV4 and BKCa ion channels in myometrial contractility, we conducted experiments, keeping in mind the fact that changes in ionic conductivity of the plasma membrane regulate spontaneous and agonist-induced contractions. On the myometrial preparations of pregnant rats usingisolated tissue tensiometry, the amplitude of contractile force was recorded under the activation of these ion channels by their selective agonists. Obtained results allow us to consider (-) – englerin A as a way to stimulate uterine contractions in case of insufficient response to oxytocin, because at a concentration of 1 nM a significant increase in contraction force was developed and did not differ statistically from the response to oxytocin or carbacholin. The use of an agonist at concentrations of 30-100 nM causes some suppression of contractility. Based on the results describing the role of TRPV4 channels, namely the reduction of uterine smooth muscle contractions in response to their selective agonist GSK1016790A administration, we suggest that the main effect of activation of these channels depends on the expression and activity of adjacent calcium-dependent potassium channels. Our experiments found that the use of the liposomal form of quercetin to activate BKCa channels inhibits the excitability of myometrial cells more effectively than that dissolved in DMSO, which is promising for the correction of premature or excessive uterine activity.

Endometrial stromal cell miR-29c-3p regulates uterine contraction.

Uterine peristalsis plays a vital role in fertility and female reproductive health. Although uterine peristalsis is thought to be correlated with some hormones and uterine pathologies, the physiological mechanisms underlying uterine peristalsis remain not quite clear. This study aimed to identify changes in miRNA in the endometrium of patients with abnormally high-frequency (hyper-) and low-frequency (hypo-) peristalsis to clarify whether miRNAs regulate uterine peristalsis. We used a miRNA microarray and RT-qPCR to identify changes in miRNA in endometrial tissue, a collagen gel contraction assay on co-cultured human endometrial stromal cells (ESCs) to analyze how the altered regulation of miRNAs influences uterine smooth muscle (USM) contraction, Western blots and other assays to elucidate the potential mechanisms involved. We found that among several differentially regulated miRNAs, miR-29c-3p was overexpressed in endometrial samples from patients with hypoperistalsis; oxytocin receptor (OXTR) expression was low in endometrial samples from patients with hypoperistalsis. Bioinformatic analysis and luciferase assays indicated that OXTR is a target of miR-29c-3p, which attenuates its expression. Additionally, downregulation of miR-29c-3p in ESC cultures increased the expression of aldo-keto reductase family 1, member C3 (AKR1C3) and increased the release of prostaglandin F2 alpha (PGF2α). Co-cultured ESCs overexpressing miR-29c-3p reduced USM cell contractions; the opposite tendency was found when ESCs were transfected with a miR-29c-3p inhibitor. To conclude, miR-29c-3p in endometrial cells regulates uterine contractility by attenuating the expression of OXTR and reducing PGF2α release.

Prostaglandin-E2 deficiency during late pregnancy and the associated increase in interleukin-1β derived from periaortic lymph nodes lead to abortion.

Prostaglandin E2 (PGE2) is a hormone with many physiological functions. During pregnancy, it is generally believed that there is a high level of PGE2 at the final stage of pregnancy, which induces the contraction of uterine smooth muscle and promotes the occurrence of childbirth. However, we find that high PGE2 levels are present throughout late pregnancy in mice, not just during childbirth, and that PGE2 deficiency induced by indomethacin during late pregnancy causes damage to the placental labyrinth and eventually leads to abortion. Interestingly, the damage is closely related to inflammation, which involves the role of inflammatory factors produced by the periaortic lymph nodes (PLNs) near the uterus. Further, through RNA sequencing, we reveal that PLNs produce a large amount of interleukin-1β (IL-1β) when exposed to PGE2 deficiency, which causes damage to the placental labyrinth, probably via destroying the extracellular matrix. Finally, events leading to abortion following indomethacin administration are effectively prevented by supplementing PGE2 or by PLN removal. These results suggest that high levels of PGE2 during late pregnancy protect fetuses from inflammatory damage related to IL-1β. This work suggests a new role of PGE2 during late pregnancy and may provide potential therapeutic strategies for pathological pregnancy.

Mechanism of Spasmogenic Activity Stimulated by Aqueous Ethanolic Leaf Extract of Mucuna pruriens on Isolated Uterine Muscle of Albino Rats

Aims: To investigate the effect of aqueous ethanolic leaf extract of this medicinal plant on isolated uterine smooth muscle strips of the rat and to determine its mechanism of action.
 Study Design: Laboratory-experimental design was used in this study.
 Place and Duration of Study: The study was carried out in the Department of Veterinary Physiology and Biochemistry of Michael Okpara University of Agriculture, Umudike, Nigeria, Department of Pharmacology and Toxicology of the Faculty of Pharmacy, University of Nigeria, Nsukka, and the Department of Veterinary Physiology and Pharmacology, University of Nigeria, Nsukka, Nigeria between June and October 2014.
 Methodology: Fresh leaves of Mucuna pruriens were identified and collected by a taxonomist from Nsukka, Nigeria. The leaves were then air dried and pulverized into powder. This was then subjected to cold extraction using petroleum ether (70-90) and 70% aqueous ethanol, after which the extract was left to dry at room temperature. Estrogenised uterine strips (12mm) were harvested from non-pregnant, sexually matured albino rats (180 g -250 g) and suspended in a 35ml organ bath containing Krebs’ physiological salt solution. The organ bath was connected to an isometric electronic force displacement transducer and a physiograph. Drugs such as Salbutamol, Isoprenaline, Adrenaline, Propranolol, Atipamezole and Prazosin were used as either agonists or antagonists to determine the mechanism of action of the extract. Atropine sulphate and Cyproheptadine were also used as test drugs. Concentrations of these drugs presented in the body of this work represent the final nutrient bath concentrations.
 Results: M. pruriens caused a dose -dependent increase in uterine muscle contraction with an EC50 of 0.88 mg/ml, n=4. The contraction was unaffected by atropine sulphate (0.042 µmol), but abolished by salbutamol (0.012-0.4 µmol), isoprenaline (0.06-0.23 µmol), and adrenaline (16 nmol). The uterine muscle contractions were enhanced by propranolol (1 µmol) in a dose- dependent manner. Prazosin (0.069-0.14 µmol) and atipamezole (3.3-13.7 nmol) were unable to abolish contractions stimulated by the extract. However, 0.2 µmol of cyproheptadine caused 80% suppression of the extract –induced uterine contraction
 Conclusion: It is concluded that aqueous ethanolic leaf extract of M. pruriens, has ability to cause uterine smooth muscle contraction hence, justifies its reported use traditionally as a uterine stimulant. This contraction is most likely exerted via the 5-HT receptor activation (activated by low concentrations of serotonin).

Selenium Deficiency Affects Uterine Smooth Muscle Contraction Through Regulation of the RhoA/ROCK Signalling Pathway in Mice.

Selenium (Se) is considered one of the essential micronutrients for humans and animals, and its effects on physiological functions are multifaceted. In the present study, we investigated the effects of Se deficiency on uterine smooth muscle contraction in mice by studying G protein Rho (RhoA)/Rho kinase (ROCK) signalling pathway-related molecules. The α-sma in smooth muscle tissue of mice was determined. The extracorporeal contraction curve for uterine smooth muscle in mice was determined. Both of these results indicate that Se deficiency impairs the contractile ability of uterine smooth muscle in mice. The expression of mRNA was measured by real-time quantitative PCR. The results showed that there was no significant change in mRNA expression of RhoA, ROCK, myosin light chain phosphatase (MLCP), or myosin light chain (MLC) in tissues. The protein levels were detected by Western blot. The results showed that there were no significant differences in RhoA, ROCK, MLCP, or MLC expression. However, compared with the CG, the concentration of phosphorylated MLC (P-MLC) increased in the SG and the concentration of P-MLC decreased in the DG. The activity of ROCK and MLCP was tested by liquid scintillation. The results suggest that the lack of Se may affect the regulation of MLCP by ROCK. Cellular experiments were performed to compare with results from tissues. There was no significant difference between the two models. The results indicated that Se deficiency affects uterine smooth muscle contraction by regulating the RhoA/ROCK signalling pathway. As the concentration of Se decreases, the activity of MLCP increases, which promotes the dephosphorylation of P-MLC, causing a decrease in contraction.

Se Regulates the Contractile Ability of Uterine Smooth Musclevia Selenoprotein N, Selenoprotein T, and Selenoprotein Win Mice.

Selenium (Se) is an essential micronutrient that maintains normal physiological functions in humans and animals. Se plays a vital role in regulating smooth muscle contractions, and selenoprotein N (SelN), selenoprotein T (SelT), and selenoprotein W (SelW) are closely related to the release of Ca2+. The present study analyzed the effects and mechanisms of SelN, SelT, and SelW in uterine smooth muscle contractions in a mouse model fed Se. The mRNA and protein levels in the uterine smooth muscle of mice were detected by qPCR, Western blot, and immunohistochemical analysis. The results showed that Se played an indispensable role in uterine smooth muscle contractions. Increased Se concentration in food increased the release of Ca2+ to a certain extent, causing CaM expression, MLCK expression, and MLC phosphorylation, which can lead to uterine smooth muscle contractions. In contrast, Se deficiency reduced the release of Ca2+ to a certain degree, thereby reducing the contractile ability of uterine smooth muscle. In this study, genes related to SelN, SelT, and SelW expression in uterine smooth muscle cells were investigated. The results showed that the Se concentration had an effect on the expression of SelN, SelT, and SelW in uterine smooth muscle cells. Se influences the release of Ca2+ through SelN, SelT, and SelW, which changes the expression of MLCK and then affects uterine smooth muscle contractions. The three selenoproteins SelN, SelT, and SelW play a very important role in uterine smooth muscle contractions, and the absence of any of these proteins affects the contractility of the uterus.

Class II PI3Ks α and β Are Required for Rho-Dependent Uterine Smooth Muscle Contraction and Parturition in Mice.

Class II phosphoinositide 3-kinases (PI3Ks), PI3K-C2α and PI3K-C2β, are highly homologous and distinct from class I and class III PI3Ks in catalytic products and domain structures. In contrast to class I and class III PI3Ks, physiological roles of PI3K-C2α and PI3K-C2β are not fully understood. Because we previously demonstrated that PI3K-C2α is involved in vascular smooth muscle contraction, we studied the phenotypes of smooth muscle-specific knockout (KO) mice of PI3K-C2α and PI3K-C2β. The pup numbers born from single PI3K-C2α-KO and single PI3K-C2β-KO mothers were similar to those of control mothers, but those from double KO (DKO) mothers were smaller compared with control mice. However, the number of intrauterine fetuses in pregnant DKO mothers was similar to that in control mice. Both spontaneous and oxytocin-induced contraction of isolated uterine smooth muscle (USM) strips was diminished in DKO mice but not in either of the single KO mice, compared with control mice. Furthermore, contraction of USM of DKO mice was less sensitive to a Rho kinase inhibitor. Mechanistically, the extent of oxytocin-induced myosin light chain phosphorylation was greatly reduced in USM from DKO mice compared with control mice. The oxytocin-induced rise in the intracellular Ca2+ concentration in USM was similar in DKO and control mice. However, Rho activation in the intracellular compartment was substantially attenuated in DKO mice compared with control mice, as evaluated by fluorescence resonance energy transfer imaging technique. These data indicate that both PI3K-C2α and PI3K-C2β are required for normal USM contraction and parturition mainly through their involvement in Rho activation.

Anoctamin Channels in Human Myometrium: A Novel Target for Tocolysis.

Spontaneous preterm labor leading to preterm birth is a significant obstetric problem leading to neonatal morbidity and mortality. Current tocolytics are not completely effective and novel targets may afford a therapeutic benefit. To determine whether the anoctamin (ANO) family, including the calcium-activated chloride channel ANO1, is present in pregnant human uterine smooth muscle (USM) and whether pharmacological and genetic modulation of ANO1 modulates USM contraction. Reverse transcription-polymerase chain reaction (RT-PCR), quantitative RT-PCR, and immunohistochemical staining were done to determine which members of the ANO family are expressed in human USM. Uterine smooth muscle strips were studied in an organ bath to determine whether ANO1 antagonists inhibit oxytocin-induced USM contractions. Anoctamin 1 small interfering RNA (siRNA) knockdown was performed to determine its effect on filamentous-/globular (F/G)-actin ratio, a measurement of actin polymerization's role in promoting smooth muscle contraction. Messenger RNA (mRNA) encoding all members of the ANO family (except ANO7) are expressed in pregnant USM tissue. Anoctamin 1 mRNA expression was decreased 15.2-fold in pregnant USM compared to nonpregnant. Anoctamin 1 protein is expressed in pregnant human USM tissue. Functional organ bath studies with pregnant human USM tissue demonstrated that the ANO1 antagonist benzbromarone attenuates the force and frequency of oxytocin-induced contractions. In human USM cells, siRNA knockdown of ANO1 decreases F-/G-actin ratios. Multiple members of the ANO family, including the calcium-activated chloride channel ANO1, are expressed in human USM. Antagonism of ANO1 by pharmacological inhibition and genetic knockdown leads to an attenuation of contraction in pregnant human USM. Anoctamin 1 is a potentially novel target for tocolysis.

The effect of flunixin meglumine, firocoxib and meloxicam on the uterine mobility of equine embryos

Embryo mobility occurs as a result of prostaglandin production by the embryo and endometrium, promoting uterine smooth muscle contractions, which propels the embryonic vesicle through the lumen. Non-steroidal anti-inflammatory drugs (NSAIDs), as flunixin meglumine, are routinely used in equine medicine and can alter the conceptus mobility if applied in early pregnancy, which may impair maternal recognition of pregnancy. The objective of this study was to evaluate and compare the effect of flunixin meglumine (FM; 1.1 mg/kg IV), firocoxib (FIRO; 0.2 mg/kg PO), and meloxicam (ML; 0.6 mg/kg, IV), on the embryo mobility. Thirty mares were divided into three groups (n = 10 per treatment). After the pregnancy diagnosis on day 12 after ovulation, the embryo mobility was evaluated by transrectal ultrasonography every 5 min for 1 h in order to visualize the location of the embryo. In all mares, three evaluations were performed: immediately before treatment (pre-treatment), after NSAID administration and 24 h after treatment. In group FM, embryo mobility decreased, from 5.8 ± 0.3 movements/hour (m/h) to 2.3 ± 0.5 m/h (p < 0.05) and, after 24 h the values were similar to the pre-treatment evaluation (5.9 ± 0.2 m/h). Likewise, ML treatment caused a decrease of embryo movements, from 5.9 ± 0.3 to 1.9 ± 0.3 m/h (p < 0.05), 24 h after treatment values were 5.7 ± 0.4 m/h. Treatment with FIRO did not interfere with embryo mobility (5.7 ± 0.4; 5.8 ± 0.3 and 5.6 ± 0.3 embryo movements in the first, second and third evaluation, respectively). In conclusion, FIRO was the only NSAID that did not alter the embryo mobility and may be the safest NSAID for use in early pregnant mares.

Fractionated Semen Collection Improved Fertility of Stallions With Seminal Vesiculitis

Embryo mobility occurs as a result of prostaglandin production by the embryo and endometrium, promoting uterine smooth muscle contractions, which propels the embryonic vesicle through the lumen. Non-steroidal anti-inflammatory drugs (NSAIDs), as flunixin meglumine, are routinely used in equine medicine and can alter the conceptus mobility if applied in early pregnancy, which may impair maternal recognition of pregnancy. The objective of this study was to evaluate and compare the effect of flunixin meglumine (FM; 1.1 mg/kg IV), firocoxib (FIRO; 0.2 mg/kg PO), and meloxicam (ML; 0.6 mg/kg, IV), on the embryo mobility. Thirty mares were divided into three groups (n = 10 per treatment). After the pregnancy diagnosis on day 12 after ovulation, the embryo mobility was evaluated by transrectal ultrasonography every 5 min for 1 h in order to visualize the location of the embryo. In all mares, three evaluations were performed: immediately before treatment (pre-treatment), after NSAID administration and 24 h after treatment. In group FM, embryo mobility decreased, from 5.8 ± 0.3 movements/hour (m/h) to 2.3 ± 0.5 m/h (p < 0.05) and, after 24 h the values were similar to the pre-treatment evaluation (5.9 ± 0.2 m/h). Likewise, ML treatment caused a decrease of embryo movements, from 5.9 ± 0.3 to 1.9 ± 0.3 m/h (p < 0.05), 24 h after treatment values were 5.7 ± 0.4 m/h. Treatment with FIRO did not interfere with embryo mobility (5.7 ± 0.4; 5.8 ± 0.3 and 5.6 ± 0.3 embryo movements in the first, second and third evaluation, respectively). In conclusion, FIRO was the only NSAID that did not alter the embryo mobility and may be the safest NSAID for use in early pregnant mares.

Association of Sodium Caseinate and Cholesterol Improved Fertility of Chilled Stallion Semen

Embryo mobility occurs as a result of prostaglandin production by the embryo and endometrium, promoting uterine smooth muscle contractions, which propels the embryonic vesicle through the lumen. Non-steroidal anti-inflammatory drugs (NSAIDs), as flunixin meglumine, are routinely used in equine medicine and can alter the conceptus mobility if applied in early pregnancy, which may impair maternal recognition of pregnancy. The objective of this study was to evaluate and compare the effect of flunixin meglumine (FM; 1.1 mg/kg IV), firocoxib (FIRO; 0.2 mg/kg PO), and meloxicam (ML; 0.6 mg/kg, IV), on the embryo mobility. Thirty mares were divided into three groups (n = 10 per treatment). After the pregnancy diagnosis on day 12 after ovulation, the embryo mobility was evaluated by transrectal ultrasonography every 5 min for 1 h in order to visualize the location of the embryo. In all mares, three evaluations were performed: immediately before treatment (pre-treatment), after NSAID administration and 24 h after treatment. In group FM, embryo mobility decreased, from 5.8 ± 0.3 movements/hour (m/h) to 2.3 ± 0.5 m/h (p < 0.05) and, after 24 h the values were similar to the pre-treatment evaluation (5.9 ± 0.2 m/h). Likewise, ML treatment caused a decrease of embryo movements, from 5.9 ± 0.3 to 1.9 ± 0.3 m/h (p < 0.05), 24 h after treatment values were 5.7 ± 0.4 m/h. Treatment with FIRO did not interfere with embryo mobility (5.7 ± 0.4; 5.8 ± 0.3 and 5.6 ± 0.3 embryo movements in the first, second and third evaluation, respectively). In conclusion, FIRO was the only NSAID that did not alter the embryo mobility and may be the safest NSAID for use in early pregnant mares.

How do Spondias mombin L (Anacardiaceae) leaves extract increase uterine smooth muscle contractions to facilitate child birth in parturient women?

Spondias mombin L. (Anacardiaceae) leaves were used in Togolese folk to treat dystocia, expel placenta and manage post-partum hemorrhage during child birth. This study aimed to establish how the extract of S. mombin leaves increase uterine smooth muscle contractions relevant to its traditional use to facilitate child birth. Tests were performed on uterus muscle strips from Sprague-Dawley rats. Central portion of uterine horns were dissected, cleaned of surrounding fat and loose connective tissue, and cut longitudinally into strips which were placed in the organ bath for isometric tension record in presence of different substances. S. mombin leaves extract increased uterine spontaneous contractions. This effect was reduced by indomethacin (2 × 10-6 M), yohimbine (2 × 10-6 M) and 2-aminoethoxydiphenyl borate (2-APB) (5 × 10-5 M), but not by atropine (3.45 × 10-8 M) and cholesterol (2.5 mg/ml). The pharmacological justification for the traditional use of S. mombin leaves to treat dystocia and expel placenta was that its hydro-ethanolic extract induced prostaglandins release, α2-adrenoceptors stimulation, calcium release from internal stores and lifted inhibitory effect of cholesterol on uterine contractions in order to increase uterine smooth muscle contractions.

S-adenosyl methionine regulates calcium channels and inhibits uterine smooth muscle contraction in rats with infectious premature delivery through the transient receptor protein 3/protein kinase Cβ/C-kinase-activated protein phosphatase-1 inhibitor of 17 kDa signaling pathway.

The aim of the present study was to investigate the effects of S-adenosyl methionine (SAMe) on infectious premature inflammatory factors and uterine contraction, and to further explore its mechanism of action via the transient receptor protein 3 (TRPC3)/protein kinase Cβ (PKCβ)/C-kinase-activated protein phosphatase-1 inhibitor of 17 kDa (CPI-17) signaling pathway, following intervention by a TRPC3 inhibitor. A rat model of premature delivery induced by lipopolysaccharide (LPS) was established. Following treatment with SAMe and inhibiting TRPC3 expression, rat serum and uterus were isolated. Hematoxylin and eosin staining was used to observe the histopathological changes in the uterus. Uterine muscle strips in vitro were selected to measure the changes in muscle tension. ELISA was utilized to measure the changes in serum inflammatory factor and oxidative stress indexes. Immunohistochemistry, western blot assay and reverse transcription-quantitative polymerase chain reaction were applied to detect calcium channel protein expression in the uterus. Western blot analysis was employed to measure the expression of TRPC3/PKCβ/CPI-17 signaling pathway-related proteins. TRPC3 was highly expressed in the uterus of rat models of premature delivery induced by LPS. Following treatment with SAMe, inflammatory cell infiltration markedly reduced in the uterus and the tension of in vitro uterine muscle strips significantly decreased. SAMe treatment suppressed inflammatory reaction and oxidative stress, and diminished L-type and T-type calcium channel protein expression. TRPC3/PKCβ/CPI-17 signaling pathway-related protein expression was also reduced. When TRPC3 expression was suppressed, the effects of SAMe against inflammation and oxidative stress were diminished. TRPC3/PKCβ/CPI-17 signaling pathway-related protein expression significantly increased. SAMe was able to reduce inflammatory reaction and oxidative stress in the uterus of rat model of infectious premature delivery induced by LPS, prolong delivery time, reduce the mortality rate of offspring rats, and serve a therapeutic role. This effect is likely achieved via the regulation of uterine contractions and childbirth through the TRPC3/PKCβ/CPI-17 signaling pathway.

S-Nitrosoglutathione Reductase Underlies the Dysfunctional Relaxation to Nitric Oxide in Preterm Labor

Tocolytics show limited efficacy to prevent preterm delivery. In uterine smooth muscle cGMP accumulation following addition of nitric oxide (NO) has little effect on relaxation suggesting a role for protein S-nitrosation. In human myometrial tissues from women in labor at term (TL), or spontaneously in labor preterm (sPTL), direct stimulation of soluble guanylyl cyclase (sGC) fails to relax myometrium, while the same treatment relaxes vascular smooth muscle completely. Unlike term myometrium, effects of NO are not only blunted in sPTL, but global protein S-nitrosation is also diminished, suggesting a dysfunctional response to NO-mediated protein S-nitrosation. Examination of the enzymatic regulator of endogenous S-nitrosoglutathione availability, S-nitrosoglutathione reductase, reveals increased expression of the reductase in preterm myometrium associated with decreased total protein S-nitrosation. Blockade of S-nitrosoglutathione reductase relaxes sPTL tissue. Addition of NO donor to the actin motility assay attenuates force. Failure of sGC activation to mediate relaxation in sPTL tissues, together with the ability of NO to relax TL, but not sPTL myometrium, suggests a unique pathway for NO-mediated relaxation in myometrium. Our results suggest that examining the action of S-nitrosation on critical contraction associated proteins central to the regulation of uterine smooth muscle contraction can reveal new tocolytic targets.

Effects of fetal hypothyroidism on uterine smooth muscle contraction and structure of offspring rats.

What is the central question of this study? Does fetal hypothyroidism in rats alter uterine contractions and structure in the adult offspring? What is the main finding and its importance? Our study indicated that maternal hypothyroidism during pregnancy increased gestational length and decreased litter size. In addition, maternal hypothyroidism caused delayed puberty onset, irregular uterine contractions and histological changes in the uterus in the female offspring. This model might contribute to a better understanding of the cellular and molecular mechanisms involved in uterine contractions in fetal hypothyroidism, studies which are not possible in humans, and might help to establish therapeutic methods for these disorders observed in uterine contractions. Thyroid hormones play an essential role in fetal growth. Hypothyroidism impairs reproductive function in both humans and animals. The aim of this study was to assess the effects of fetal hypothyroidism on uterine smooth muscle contraction and structure in the adult offspring. The control group of female Wistar rats consumed tap water, whereas the hypothyroid group received water containing 0.025% of 6-propyl-2-thiouracial throughout gestation from mating until delivery. Isometric contractility and histological changes in uterine tissue were evaluated in the adult female offspring. We tested the effects of carbachol (10-10 -10-3 m) and oxytocin (10-13 -10-8 m) on uterine smooth muscle contraction in the fetal hypothyroid (FH) and control groups. Compared with control uteri, carbachol induced contractions with lower amplitude in the FH group (area under the curve: 1820.0±250.0 versus 1370.0±125.0a.u., control versus FH group, respectively, P<0.001) and frequency (86.4±7.3 versus 37.0±6.1a.u., P<0.001). Likewise, after exposure to oxytocin the amplitude (6614.0±492.2 versus 4793.0±735.2a.u., P<0.001) and frequency (367.4±32.0 versus 167.0±39.0a.u., P<0.001) of uterine contractions in the FH group were significantly lower than in the control group. In addition, the thickness of the endometrium and smooth muscle layer and the cross-sectional area of the uterus were also significantly lower in the FH group. Gestational length was longer and litter size smaller in FH rats compared with control animals; FH offspring also had delayed puberty. In conclusion, thyroid hormone deficiency during pregnancy increased gestational length and decreased litter size; in the offspring, it delayed puberty onset, reduced uterine rhythmic contractions and resulted in uterine structural changes.

Monosodium glutamate impairs the contraction of uterine visceral smooth muscle ex vivo of rat through augmentation of acetylcholine and nitric oxide signaling pathways

The aim of the study was to examine the toxic effects of Monosodium glutamate (MSG), an extensively used food additive, on the contraction of uterine visceral smooth muscle (UVSM) in rat and to elucidate the probable neurocrine mechanism involved in it. MSG produced significant potentiation of the force and inhibition of frequency of uterus recorded ex vivo in chronic MSG exposure and in single dose acute experiments. MSG also produced significant potentiation of force of acetylcholine induced contraction and no alterations in atropine induced contraction of uterus. Further, MSG produced significant increase in force and frequency of contraction of neostigmine incubated uterus. We have found significant potentiation of the post pause force of contraction of uterus when MSG was applied in adrenaline incubated uterus. MSG also produced significant decrease in frequency of contraction of sodium nitroprusside incubated uterus; increase in frequency of N-ω-Nitro-l-Arginine Methyl Ester incubated uterus and no significant changes in frequency of contraction of methylene blue incubated uterus. These results indicate that MSG potentiates the force of contraction of UVSM predominantly by augmenting the activity of cholinergic intrinsic efferents and inhibits the frequency of contraction probably by augmenting the activity of nitrergic efferents. In conclusion, MSG potentiates the force and inhibits the frequency of contraction of UVSM, and the MSG induced effect is probably mediated through the augmentation of acetylcholine and nitric oxide signaling pathways.

The Effects of Ibogaine on Uterine Smooth Muscle Contractions: Relation to the Activity of Antioxidant Enzymes

Ibogaine is an indole alkaloid originally extracted from the root bark of the African rainforest shrub Tabernanthe iboga. It has been explored as a treatment for substance abuse because it interrupts drug addiction and relieves withdrawal symptoms. However, it has been shown that ibogaine treatment leads to a sharp and transient fall in cellular ATP level followed by an increase of cellular respiration and ROS production. Since contractile tissues are sensitive to changes in the levels of ATP and ROS, here we investigated an ibogaine-mediated link between altered redox homeostasis and uterine contractile activity. We found that low concentrations of ibogaine stimulated contractile activity in spontaneously active uteri, but incremental increase of doses inhibited it. Inhibitory concentrations of ibogaine led to decreased SOD1 and elevated GSH-Px activity, but doses that completely inhibited contractions increased CAT activity. Western blot analyses showed that changes in enzyme activities were not due to elevated enzyme protein concentrations but posttranslational modifications. Changes in antioxidant enzyme activities point to a vast concentration-dependent increase in H2O2 level. Knowing that extracellular ATP stimulates isolated uterus contractility, while H2O2 has an inhibitory effect, this concentration-dependent stimulation/inhibition could be linked to ibogaine-related alterations in ATP level and redox homeostasis.

Selenoprotein N Was Required for the Regulation of Selenium on the Uterine Smooth Muscle Contraction in Mice.

Selenium (Se) is an essential micronutrient affecting various aspects of health. The balance of the Se concentration has an important protective and promoter effect on physiological function in inducing muscular disorders in smooth muscle. Selenoprotein N (SelN) is closely related to Ca2+ release. The present study aimed to determine the effects and mechanism of action of dietary Se on uterine smooth muscle contraction via SelN using a mouse model. Quantitative polymerase chain reaction (qPCR) analysis was performed to detect mRNA levels. Western blotting was performed to detect protein levels. The results of the immunohistochemical analysis showed that Se had an effect on the uterine smooth muscle. The Se-supplement increased the release of Ca2+, Ca2+-calmodulin (CaM) expression, myosin light chain kinase (MLCK) expression, and myosin light chain (MLC) phosphorylation but did not affect ROCK and RhoA in uterine smooth muscle. Furthermore, the lack of Se showed an opposite impact. The effects of Se regulation were closely related to SelN. The interference of mouse SelN was performed on the uterine smooth muscle cell. Additionally, the results displayed the regulation of Se on the release of Ca2+, CaM expression, MLCK expression, and MLC phosphorylation were significant inhibited, and there was no effect on ROCK and RhoA. In conclusion, Se played an important role in regulating the process of contraction in uterine smooth muscle with SelN.

The Effect of Hydro-Alcoholic Extract of Rosa damascena on Uterine Constriction of Virgin Rats

Background: Few studies have evaluated the effect of Rosa damascena (R. damascena) on uterine smooth muscle contraction and dysmenorrhea; but, their ‎results were inconsistent. Objectives: The aim of the study was to consider the effect of alcoholic extract of R. damascena flower on uterine smooth muscle contraction amplitude, duration, and frequency in virgin rats. Methods: Thirty adult Wistar rats (180 - 220 g) were randomly divided into 3 groups including control, extract, and oxytocin plus extract. After anesthesia, 1.5 cm of the uterine horn was cut and placed in an organ bath. The contractile responses of the uterine smooth muscle to a cumulative concentration of alcoholic extract of R. damascena flower (1, 2, and 4 mg/mL) and to oxytocin (4 mU/mL) plus alcoholic extract of R. damascena were recorded. The extract or oxytocin was diluted in 0.2 ml of De Jalon solution and added to the organ bath. The amplitude, duration, and interval of contractions were recorded. Results: The alcoholic extract of R. damascena (4 mg/mL) significantly reduced the basal contractions ‎of ‎uterine smooth muscle (P = 0.004). Rosa damascena (4 mg/mL) significantly diminished oxytocin-induced uterine smooth muscle contractions (P = 0.026). The extract of R. damascena had no significant effect on the duration of normal or oxytocin-induced contractions in uterine smooth muscle. However, R. damascena (4 mg/mL) significantly reduced the frequency of uterine contraction in normal (P = 0.006) and oxytocin-induced contractions (P = 0.014). Conclusions: Rosa damascena extract reduced the amplitude and frequency of the basal and oxytocin-induced contractions in the uterine smooth muscle of virgin rats. The extract may relieve dysmenorrhea and premature labor, which needs further study for more clarification.