Nonpregnant Rats Research Articles

Pregnancy alters fatty acid metabolism, glucose regulation, and detoxification of the liver in synchrony with biomechanical property changes

Pregnancy places a metabolic burden on the body including the liver, which is responsible for ensuring adequate nutrition for the maternal and fetal systems. To gain a better understanding of liver adaptation, this study investigates metabolic shifts occurring in livers of pregnant rats. Metabolic capacities of the livers of pregnant and non-pregnant female Wistar rats were assessed using comprehensive metabolic models. Kinetic metabolic models were generated for each animal based on protein abundance data from proteomics analysis allowing for a subject-specific assessment of hepatic metabolic functions. Data are available via ProteomeXchange with identifier PXD050758. Additionally, tissue stiffness, viscosity, and water diffusion obtained from magnetic resonance imaging and elastography were correlated with metabolic capabilities to study the relationship between metabolic function and biophysical properties. Proteome profiling revealed differences in protein expression in the livers of pregnant and non-pregnant animals. Functional analysis showed significant variations in metabolic capacities. Livers of pregnant rats had reduced capacities in carbohydrate and fatty acid metabolism, along with altered urea synthesis. Additionally, there were associations between metabolic functions and biophysical properties highlighting potential links between changes in liver structure and metabolic capacities during pregnancy. In summary, our work reveals extensive hepatic metabolic changes in pregnant rats. The liver adapts its metabolic capacities to ensure whole-body metabolic homeostasis but may struggle to counteract nutritional challenges, such as hypoglycemia. The study, employing a personalized approach combining proteomics, kinetic modeling, and advanced imaging, sheds light on the intricate interplay between hepatic adaptations and medical imaging markers, providing a foundation for further investigations into the implications for maternal and fetal health.

Acute Toxicity Assessment of Cream Ethanolic Extract of Vitex pinnata Bark from Central Kalimantan.

Vitex pinnata bark has the ability to scavenge free radicals and has antimicrobial activity, thus accelerating wound healing. The formulation of V. pinnata bark preparations has good organoleptic properties, homogenity, pH, dispersion, and absorption. We studied the acute toxicity of V. pinnata skin cream in Wistar rats according to OECD guidelines 402. Seven nulliparous, non-pregnant female Wistar rats were exposed 2000 mg/kg of body weight. There were no signs of toxicity in any behavioral, necropsy dan histopathological changes. The Globally Harmonized System classified V. pinnata cream extract as category 5 (unclassified) with LD50 more than two thousand mg/kg.

Coumarins with Different Substituents from Leonurus japonicus Have Opposite Effects on Uterine Smooth Muscle.

Leonurus japonicus Houtt is an exceptional medicinal herb used to treat obstetrical and gynecological diseases in traditional Chinese medicine, and it has significant effects on the treatment of dysmenorrhea and postpartum hemorrhage. This study investigated the effects of coumarins with diverse substituent groups from L. japonicus on isolated uterine smooth muscle and the preliminary mechanism of the most effective compound. Eight coumarins isolated from L. japonicus were assessed for their effects on the isolated uterine smooth muscle of nonpregnant rats in vitro. Coumarins 1 and 2 significantly promoted the contraction of rat uterine smooth muscle strips, whereas coumarins 3-5 showed remarkable relaxing effects against oxytocin (OT)-induced rat uterine smooth muscle contraction. Further mechanism investigations revealed that bergapten (coumarin 1) significantly increased the level of Ca2+ in uterine tissues by promoting extracellular Ca2+ influx and intracellular Ca2+ release, which were related to the activation of L-type Ca2+ channels and α-receptors. By contrast, osthole (coumarin 5), an α receptor antagonist, inhibited OT-induced uterine smooth muscle contraction by decreasing the level of Ca2+ in uterine tissues via inhibition of extracellular Ca2+ influx and intracellular Ca2+ release. This study demonstrates that the coumarins from L. japonicus are effective substances for regulating uterine smooth muscle contraction, but different coumarins with diverse substituent groups have different, even opposite effects. It can be inferred that coumarins are closely related to the efficacy of L. japonicus in the treatment of dysmenorrhea and postpartum hemorrhage.

Three-dimensional virtual histology of the rat uterus musculature using micro-computed tomography.

Contractions of the uterus play an important role in menstruation and fertility, and contractile dysfunction can lead to chronic diseases such as endometriosis. However, the structure and function of the uterus are difficult to interrogate in humans, and thus animal studies are often employed to understand its function. In rats, anatomical studies of the uterus have typically been based on histological assessment, have been limited to small segments of the uterine structure, and have been time-consuming to reconstruct at the organ scale. This study used micro-computed tomography imaging to visualise the muscle structures in the entire non-pregnant rat uterus and assess its use for 3D virtual histology. An assessment of the rodent uterus is presented to (i) quantify muscle thickness variations along the horns, (ii) identify predominant fibre orientations of the muscles and (iii) demonstrate how the anatomy of the uterus can be mapped to 3D volumetric meshes via virtual histology. Micro-computed tomography measurements were validated against measurements from histological sections. The average thickness of the myometrium was found to be 0.33 ± 0.11 mm and 0.31 ± 0.09 mm in the left and right horns, respectively. The micro-computed tomography and histology thickness calculations were found to correlate strongly at different locations in the uterus: at the cervix, r = 0.87, and along the horn from the cervical end to the ovarian end, respectively, r = 0.77, r = 0.89 and r = 0.54, with p < 0.001 in every location. This study shows that micro-computed tomography can be used to quantify the musculature in the whole non-pregnant uterus and can be used for 3D virtual histology.

Calix[4]arene С-956 as a selective inhibitor of Ca2+-pump of the plasma membrane and a modulator of the contractile function in the myometrium

Background. At present, creating and testing pharmacological instruments for selective inhibition of Са2+-pump of the plasma membrane, which would become the foundation for medical preparations, for instance, for the treatment of the impaired excitability of the cardiac and smooth muscles, remains critically significant. We have demon­strated in our previous experiments that calix[4]arene С-956 is effective in inhibi­ting Са2+, Mg2+-ATPase activity of the plasma membrane of myometrium cells. The aim of this study was to investigate the regularities and mechanisms of the impact of calix[4]arene С-956 on Са2+-transporting activity of Са2+, Mg2+-ATPase of the plasma membrane (PM) and the contractile function of rat myometrium. Materials and Methods. The experiments were conducted using outbred white non-pregnant rats. Ca2+-transporting activity of myocytes PM preparations loaded with Ca2+-sensitive fluorescent probe fluo-4 AM was investigated. The registration of the contractile activity in the preparations of longitudinal smooth muscles of uterine horns with preserved endothelium was done in the isometric mode. Results. It was determined that calix[4]arene C-956 causes blocking of the transport function of the calcium pump of preparations of plasma membranes of uterine myocytes. The C-956 compound causes an increase in the amplitude of spontaneous contractions and a change in their mechanokinetic parameters during a short-term effect on multicellular preparations of rat myometrium. Calix[4]arene C-956 also significantly affects the contractions caused by high-potassium depolarization of the PM and oxytocin, increa­sing their amplitude and decreasing the rate of relaxation. Blocking the synthesis of nitric oxide significantly enhances the effects of C-956 on spontaneous and high-potassium- and oxytocin-induced contractions of the myometrium. Conclusions. The results of our research indicate that the main target of the action of calix[4]arene C-956 on myocytes is the calcium pump of the PM. With the preliminary inhibition of nitric oxide synthases followed by the use of C-956, we were able to fully demonstrate the contribution of the calcium pump of the PM to the regulation of uterine contractions.

Spatial Activation of Autophagy in Human Placenta-Related Tissue During Labor: A Possible Mechanism for Labor Onset.

To explore the mechanisms of labor by investigating the autophagy of placental and fetal membranes tissue in normal pregnant women. Placenta and fetal membranes were collected from women with singleton pregnancies without any medical complications and from women who delivered vaginally (labor-initiated group; L group) or by caesarean section (labor-noninitiated group; NL group). Autophagosomes were observed by transmission electron microscopy (TEM). Immunofluorescence and western blotting (WB) were used to detect protein levels of the autophagy markers LC3A and LC3B. TEM, immunohistochemistry (IHC), and WB were used to compare autophagy in different parts of the placenta and fetal membranes in the L and NL groups. The expression of LC3B/LC3A, ROCK1, and ROCK2 in the placenta of nonpregnant and pregnant rats was detected by WB and IHC. TEM and IHC results showed an increase in the number of autophagosomes and autophagic lysosomes in the L group, and WB results indicated an increase in the LC3B/A ratio between the placenta and fetal membranes in the L group. Autophagy was significantly increased on the maternal side of the placenta in the L group, and the level of autophagy became higher near rupture in the fetal membranes and near the point where the umbilical cord joins the placenta in the L group. The LC3B/A ratio increased and ROCK1 and ROCK2 levels decreased in postnatal rats. Autophagy can occur in the placenta and fetal membranes and its activity is higher at the onset of labor, suggesting a role in labor.

Isoflurane increases the activity of the vascular matrix metalloproteinase-2 in non-pregnant rats and increases the nitric oxide metabolites in pregnancy.

Surgeries that require general anesthesia occur in 1.5-2% of gestations. Isoflurane is frequently used because of its lower possibility of affecting fetal growth. Therefore, we examined the isoflurane anesthesia-induced effects on maternal hemodynamic and vascular changes. We hypothesized that isoflurane would enhance endothelium-dependent vasodilation as a consequence of increased nitric oxide and decreased metalloproteinases (MMPs). Female rats (n=28) were randomized into 4 groups (7 rats/group): conscious (non-anesthetized) non-pregnant group, non-pregnant anesthetized group, conscious pregnant group, and pregnant anesthetized group. Anesthesia was performed on the 20th pregnancy day, and hemodynamic parameters were monitored. Nitric oxide metabolites, gelatinolytic activity of MMP-2 and MMP-9, and the vascular function were assessed. Isoflurane caused no significant hemodynamic changes in pregnant compared with non-pregnant anesthetized group. Impaired acetylcholine-induced relaxations were observed only in conscious non-pregnant group (by approximately 62%) versus 81% for other groups. Phenylephrine-induced contractions were greater in endothelium-removed aorta segments of both pregnant groups (with or without isoflurane) compared with non-pregnant groups. Higher nitric oxide metabolites were observed in anesthetized pregnant in comparison with the other groups. Reductions in the 75 kDa activity and concomitant increases in 64 kDa MMP-2 isoforms were observed in aortas of pregnant anesthetized (or not) groups compared with conscious non-pregnant group. Isoflurane anesthesia shows stable effects on hemodynamic parameters and normal MMP-2 activation in pregnancy. Furthermore, there were increases in nitric oxide bioavailability, suggesting that isoflurane provides protective actions to the endothelium in pregnancy.

Effects of Liquid Fructose Supplementation and Chronic Unpredictable Stress on Uterine Contractile Activity in Nonpregnant Rats.

Increased fructose consumption and chronic stress, the major characteristics of modern lifestyle, impact human health; however, the consequences of their combination on the uterus remain understudied. In this study, we investigated contractile activity, morphology, and intracellular activity of antioxidant enzymes in uteri from virgin Wistar rats subjected to liquid fructose supplementation and/or unpredictable stress over 9 weeks. Contractile activity and uterine response to oxytocin or adrenaline were examined ex vivo using isolated bath chambers. Fructose supplementation, irrespective of stress, affected uterine morphology by increasing endometrium while decreasing myometrium volume density, attenuated uterine response to increasing doses of oxytocin, and increased glutathione peroxidase activity. Stress, irrespective of fructose, attenuated dose-dependent adrenaline-induced uterine relaxation. Stress, when applied solely, decreased mitochondrial superoxide dismutase activity. In the combined treatment, irregular estrous cycles and both reduced response to oxytocin and to adrenaline (as a consequence of fructose consumption and exposure to stress), along with fructose-related alteration of uterine morphology, were detected. In conclusion, fructose and stress affect uterine contractile activity, irrespective of each other, by inducing completely distinct responses in isolated uteri. In the combined treatment, the effects of both factors were evident, suggesting that the combination exerts more detrimental effects on the uterus than each factor individually.

Depletion of hepatic glutathione and adenosine by glucocorticoid exposure in Wistar rats is pregnancy-independent

Liver diseases have gained increasing attention due to their substantial impact on health, independently as well as in association with cardio-metabolic disorders. Studies have suggested that glutathione and adenosine assist in providing protection against oxidative stress and inflammation while glucocorticoid (GC) therapy has been associated with chronic inflammatory disorders, even in pregnancy. The implications of Glucocorticoid exposure on maternal health and fetal growth is a concern, however, the possible role of glutathione and adenosine has not been thoroughly investigated. The study therefore hypothesize that exposure to glucocorticoids leads to depletion of hepatic glutathione and adenosine levels, contributing to oxidative stress and tissue injury. Additionally, we aim to investigate whether the effects of glucocorticoids on hepatic health are pregnancy dependent in female rats. Twelve Pregnant and twelve age-matched non-pregnant rats were used for this study; an exogenous administration of glucocorticoid (Dex: 0.2 mg/kg) or vehicle (po) was administered to six pregnant and six non-pregnant rats from gestational day 14 to 19 or for a period of 6 days respectively. Data obtained showed that GC exposure led to a decrease in hepatic glucose-6-phosphate dehydrogenase, glutathione peroxidase, GSH/GSSG ratio and adenosine content in both pregnant and non-pregnant rats. In addition, increased activities of adenosine deaminase and xanthine oxidase, along with increased production of uric acid and increased levels of lactate dehydrogenase, aspartate aminotransferase, alanine transferase, alkaline phosphatase and gamma-glutamyl transferase were observed. In summary, the study indicates that GC-induced liver damage is underlined by depleted hepatic adenosine and glutathione levels as well as elevated markers of tissue inflammation and/or injury. Furthermore, the findings suggest that the effects of GC exposure on hepatic health are pregnancy independent.

Thrombin in Pregnancy and Preeclampsia: Expression, Localization, and Vasoactivity in Brain and Microvessels From Rats.

Thrombin is a coagulation factor increased in pregnancy and further increased in preeclampsia (PE), a hypertensive disorder. Thrombin is also expressed in the brain and may have a nonhemostatic role. We characterized thrombin expression and vasoactivity in brain cerebral parenchymal arterioles (PAs) in rat models of pregnancy and PE. PAs were isolated and pressurized from nonpregnant (NP) and late-pregnant (LP) rats and rats with experimental preeclampsia (ePE). Reactivity to thrombin (1-50 U/mL) was measured in the absence and presence of inhibition of cyclooxygenase and nitric oxide synthase. Plasma levels of prothrombin, thrombin-antithrombin (TAT), tissue plasminogen activator, and plasminogen activator inhibitor-1 (PAI-1) and cerebrospinal fluid levels of TAT were compared using enzyme-linked immunosorbent assay. Expression of protease-activated receptor types 1 and 2 in PAs were measured by Western blot and immunohistochemistry. Neuronal thrombin expression was quantified in brains from all groups by immunohistochemistry. Prothrombin and TAT were elevated in ePE plasma compared with NP and LP. TAT was detected in cerebrospinal fluid from all groups and significantly elevated in LP (NP: 0.137 ± 0.014 ng/mL, LP: 0.241 ± 0.015 ng/mL, ePE: 0.192 ± 0.028 ng/mL; P < 0.05). Thrombin caused modest vasoconstriction in PAs from all groups regardless of cyclooxygenase or nitric oxide synthase inhibition. PAR1 and PAR2 were found in PAs from all groups colocalized to smooth muscle. Thrombin expression in central neurons was decreased in both LP and ePE groups compared with NP. These findings suggest a role for thrombin and other hemostatic changes during pregnancy and PE beyond coagulation.

Multichannel mapping of in vivo rat uterine myometrium exhibits both high and low frequency electrical activity in non-pregnancy

The uterus exhibits intermittent electrophysiological activity in vivo. Although most active during labor, the non-pregnant uterus can exhibit activity of comparable magnitude to the early stages of labor. In this study, two types of flexible electrodes were utilized to measure the electrical activity of uterine smooth muscle in vivo in anesthetized, non-pregnant rats. Flexible printed circuit electrodes were placed on the serosal surface of the uterine horn of six anesthetized rats. Electrical activity was recorded for a duration of 20–30 min. Activity contained two components: high frequency activity (bursts) and an underlying low frequency ‘slow wave’ which occurred concurrently. These components had dominant frequencies of 6.82 ± 0.63 Hz for the burst frequency and 0.032 ± 0.0055 Hz for the slow wave frequency. There was a mean burst occurrence rate of 0.76 ± 0.23 bursts per minute and mean burst duration of 20.1 ± 6.5 s. The use of multiple high-resolution electrodes enabled 2D mapping of the initiation and propagation of activity along the uterine horn. This in vivo approach has the potential to provide the organ level detail to help interpret non-invasive body surface recordings.

The disrupting effect of chlormequat chloride on growth hormone is associated with pregnancy

Since chlormequat chloride is widely applied as a plant growth regulator in agriculture and horticulture, its exposure through food consumption is common. We demonstrated previously that chlormequat chloride exposure during pregnancy led to embryos with bigger sizes associated with higher levels of growth hormone (GH) on gestation day 11 (GD11). However, the dose-effect relationship of chlormequat chloride at a lower dose range was not established, and the underlying mechanisms of its promoting effects on embryonic growth and development were not fully elucidated. To address these, pregnant rats were orally exposed to chlormequat chloride at 0, 0.05, 0.5 and 5 mg/kg.bw from GD0 to 11 and the embryonic growth and growth related hormones were evaluated on GD11. We found that the growth and development of the embryos was significantly promoted in a dose dependent manner by chlormequat chloride. Chlormequat chloride also increased embryonic GH, GH releasing hormone (GHRH), and somatostatin (SRIF), and inhibited the embryonic cAMP dependent protein kinase A (PKA) signaling pathway. Chlormequat chloride increased GH synthesis modulated by GHRH/SRIF-PKA-Pituitary specific transcription factor 1 (Pit-1) in the maternal rats. Intriguingly, chlormequat chloride did not show any effects on GH and PKA signaling pathways in the non-pregnant female rats. These findings together suggest that the disrupting effect of chlormequat chloride on GH is associated with pregnancy.

Advanced maternal age alters cardiac functional and structural adaptations to pregnancy in rats.

A significant number of pregnancies occur at advanced maternal age (>35 yr), which is a risk factor for pregnancy complications. Healthy pregnancies require massive hemodynamic adaptations, including an increased blood volume and cardiac output. There is growing evidence that these cardiovascular adaptations are impaired with age, however, little is known about maternal cardiac function with advanced age. We hypothesized that cardiac adaptations to pregnancy are impaired with advanced maternal age. Younger (4 mo; ∼early reproductive maturity in humans) and aged (9 mo; ∼35 yr in humans) pregnant Sprague-Dawley rats were assessed and compared with age-matched nonpregnant controls. Two-dimensional echocardiographic images were obtained (ultrasound biomicroscopy; under anesthesia) on gestational day 19 (term = 22 days) and compared with age-matched nonpregnant rats (n = 7-9/group). Left ventricular structure and function were assessed using short-axis images and transmitral Doppler signals. During systole, left ventricular anterior wall thickness increased with age in the nonpregnant rats, but there was no age-related difference between the pregnant groups. There were no significant pregnancy-associated differences in left ventricular wall thickness. Calculated left ventricular mass increased with age in nonpregnant rats and increased with pregnancy only in young rats. Compared with young pregnant rats, the aortic ejection time of aged pregnant rats was greater and Tei index was lower. Overall, the greater aortic ejection time and lower Tei index with age in pregnant rats suggest mildly altered cardiac adaptations to pregnancy with advanced maternal age, which may contribute to adverse outcomes in advanced maternal age pregnancies.NEW & NOTEWORTHY We demonstrated that even before the age of reproductive senescence, rats show signs of age-related alterations in cardiac structure that suggests increased cardiac work. Our data also demonstrate, using an in vivo echocardiographic approach, that advanced maternal age in a rat model is associated with altered cardiac function and structure relative to younger pregnant controls.

Changes in the conflicting nongenomic effects of progesterone in rat myometrium during pregnancy

AimsAlthough the functions of progesterone in the myometrium are well-established, the nongenomic effects of progesterone in pregnant myometrial contractions are still unclear. Therefore, this study aimed to investigate changes in the nongenomic effects of progesterone during pregnancy. Main methodsMyometrial strips were obtained from non-pregnant, pregnant, and postpartum rats, and the nongenomic effects of progesterone in the myometrium during pregnancy were examined. Additionally, the influence of actinomycin D and cycloheximide and the effects of Org OD-02-0 (a specific membrane progesterone receptor (mPR) agonist) in the myometrium were investigated. Moreover, DNA microarray and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to identify genes involved in progesterone-induced effects in the myometrium. Key findingsProgesterone did not cause rhythmic contractions in non-pregnant myometrium but induced rhythmic contractions in pregnant myometrium, with the effects peaking at 20 d + 8 h of pregnancy. However, myometrial contractions decreased after delivery and were restored to non-pregnant levels at 7 d postpartum. Additionally, progesterone stably inhibited high KCl-induced myometrial contractions during pregnancy. Moreover, the nongenomic effects of progesterone were unaffected by actinomycin D or cycloheximide, and Org OD-02-0 effectively mimicked these effects. DNA microarray analysis and qRT-PCR revealed a significant increase in mPRβ gene expression during pregnancy. However, mPRα, mPRγ, mPRδ, and mPRε expression levels remained unchanged. SignificanceThe stimulatory nongenomic effect of progesterone, which was inducible and mPRβ-dependent during pregnancy, may be involved in parturition. The inhibitory effect, which was constitutive and depended on other mPRs, may be involved in pregnancy maintenance.

Gestational administration of aqueous leaf extract of Jatropha tanjorensis alleviated postpartum emotional and cognitive dysfunction in rats (Wistar strain).

This study examines the effect of gestational administration of aqueous leaf extract of Jatropha tanjorensis (JT) on postpartum-like behavioural outcomes to delineate its possibility as a prophylactic, therapeutic agent in the treatment of postpartum symptoms. Inseminated female rats (120-150g) were grouped into two-control and JT group (n=10). Control received 20 ml/kg of distilled water and JT group received 500 mg/kg of JT orally once daily for 21 days in gestation. Non-pregnant rats were excluded from the study. Parameters assessed at postpartum include antidepressant-like (force swim test, FST; tail suspension-test, TST), locomotor (open field test, OFT), anxiolytic-like (elevated plus maze, EPM; light-dark box, LDB), learning and memory (T-maze; novel object recognition task, NORT), social (nest score) and analgesic-like (hot plate test, HPT; tail flick test, TFT) behaviours. JT increased (P<0.05) mobility and latency to immobility durations in FST and TST; open arm entry (P<0.001) and duration (P<0.01) in EPM and light box duration (P<0.05) in LDB; locomotion and exploration, but reduced anxiety-like levels in EPM, LDB and OFT. It increased nest score (P<0.05); mean retraction time (P<0.01) of TFT. JT showed positive score for short and long term memory in NORT and improved percentage alternation in T-maze though not significant compared to control. In conclusion, the aqueous extract has a therapeutic effect that reduces postpartum-like depression and anxiety, and improves locomotor activity. JT can be a preventive and adjuvant therapeutic option for pregnant women.

Mechanisms of acupuncture for primary dysmenorrhea based on PI3K/Akt/mTOR signaling pathway in rats.

To observe the effect of electroacupuncture(EA) on phosphatidylinositol-3-kinases(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR) signaling pathway of uterus tissue in rats with primary dysmenorrhea(PDM), so as to investigate its mechanisms underlying improvement of PDM. Thirty healthy non-pregnant female SD rats were randomly divided into blank, model and EA groups, with 10 rats in each group. The PDM model was established by subcutaneous injection of estradiol diphenhydrate combined with intraperitoneal injection of oxytocin. For rats of the EA group, EA(50 Hz, a tolerable current intensity) was applied to "Guanyuan"(CV4) and bilateral "Sanyinjiao"(SP6) for 20 min, once a day for 10 consecutive days. The number of writhing, wri-thing score, and writhing latency were observed. The uterine histopathological changes were observed by H.E. staining, and the ultrastructural changes of uterine tissue cells in each group were observed by transmission electron microscopy. The contents of prostaglandin E2(PGE2), prostaglandin F2α(PGF2α) and ratios of PGF2α/PGE2 in the serum and uterine tissue were detected by ELISA. The relative expression levels of PI3K, Akt and mTOR and their phosphorylation proteins in the uterine tissue were detected by Western blot and the ratios were calculated. Compared with the blank group, the number and score of writhing, latency of writhing, pathological injury score, contents of PGF2α and ratios of PGF2α/PGE2 in the serum and uterine tissue, and the levels of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR in the uterine tissue were significantly increased in the model group(P<0.01, P<0.05), while contents of PGE2 in the serum and uterine tissue were reduced(P<0.05). In comparison with the model group, the number of writhing and writhing score, pathological injury score, contents of PGF2α and ratios of PGF2α/PGE2 in both the serum and uterine tissue, the levels of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR were obviously decreased(P<0.05, P<0.01), whereas the writhing latency was considerably prolonged in the EA group(P<0.01), with elevated contents of PGE2 in the serum and uterine tissue(P<0.05). H.E. staining showed slight dilation of uterine glandular cavity, and severe endometrial edema with extensive cell shedding and a large number of vacuole-like degeneration, apoptosis, pyknosis or fragmentation or disappearance of the nucleus, and neutrophil infiltration in the model group, which were relatively milder in the EA group. Ultrastructural results showed irregular fibroblasts of uterine tissue cells, obvious cytoplasmic edema, reduction in cytoplasmic electron density, seriously irregular nuclei, severe edema of mitochondria with dissolved matrix, fracture and disappearance of mitochondrial crests and vacuolation, and moderate dilation of rough endoplasmic reticulum in the model group, which were milder in the EA group. EA can improve pain and uterine inflammatory response in PDM rats, which may be associated with its functions in reducing uterine PGF2α and down-regulating PI3K/Akt/mTOR signaling.

Pharmacokinetic characterisation of a valproate Autism Spectrum Disorder rat model in a context of co-exposure to α-Hexabromocyclododecane

Assessing the role of α-hexabromocyclododecane α-HBCDD as a factor of susceptibility for Autism Spectrum disorders by using valproic acid-exposed rat model (VPA) required characterizing VPA pharmacokinetic in the context of α-HBCDD-co-exposure in non-pregnant and pregnant rats. The animals were exposed to α-HBCDD by gavage (100 ng/kg/day) for 12 days. This was followed by a single intraperitoneal dose of VPA (500 mg/kg) or a daily oral dose of VPA (500 mg/kg) for 3 days. Exposure to α-HBCDD did not affect the pharmacokinetics of VPA in pregnant or non-pregnant rats. Surprisingly, VPA administration altered the pharmacokinetics of α-HBCDD. VPA also triggered higher foetal toxicity and lethality with the PO than IP route. α-HBCDD did not aggravate the embryotoxicity observed with VPA, regardless of the route of exposure. Based on this evidence, a single administration of 500 mg/kg IP is the most suitable VPA model to investigate α-HBCDD co-exposure.

Progression of renal damage and tubular regeneration in pregnant and non-pregnant adult female rats inoculated with a sublethal dose of Shiga toxin 2

BackgroundShiga toxin-producing Escherichia coli is the main cause of post-diarrheal hemolytic uremic syndrome (HUS) which produces acute kidney injury mainly in children, although it can also affect adults. The kidneys are the organs most affected by Shiga toxin type 2 (Stx2) in patients with HUS. However, previous studies in pregnant rats showed that a sublethal dose of Stx2 causes severe damage in the uteroplacental unit and induces abortion, whereas produces mild to moderate renal damage. The aim of the present work was to study the progression of renal injury caused by a sublethal dose of Stx2, as well as renal recovery, in pregnant and non-pregnant rats, and to investigate whether pregnancy physiology may affect renal damage progression mediated by Stx2. MethodsRenal function and histopathology was evaluated in pregnant rats intraperitoneally injected with a sublethal dose of Stx2 (0.5 ng/g bwt) at the early stage of gestation (day 8 of gestation), and results in these rats were compared over time with those observed in non-pregnant female rats injected with the same Stx2 dose. Hence, progression of cell proliferation and dedifferentiation in renal tubular epithelia was also investigated. ResultsThe sublethal dose of Stx2 induced abortion in pregnant rats as well as a significant more extended functional and histological renal injury in non-pregnant rats than in pregnant rats. Stx2 also caused decreased ability to concentrate urine in non-pregnant rats compared to their controls. However, renal water handling in pregnant rats was not altered by Stx2, and was significantly different than in non-pregnant rats. The greatest renal injury in both pregnant and non-pregnant rats was observed at 4 days post-Stx2 injection, and coincided with a significant increase in tubular epithelial proliferation. Expression of mesenchymal marker vimentin in tubular epithelia was consistent with the level of tubular damage, being higher in non-pregnant rats than in pregnant rats. Recovery from Stx2-induced kidney injury was faster in pregnant rats than in non-pregnant rats. ConclusionsAdaptive mechanisms developed during pregnancy such as changes in water handle and renal hemodynamic may contribute to lessen the Stx2-induced renal injury, perhaps at the expense of fetal loss.

Evaluating the toxicokinetics of some metabolites of a C6 polyfluorinated compound, 6:2 fluorotelomer alcohol in pregnant and nonpregnant rats after oral exposure to the parent compound

The 6:2 fluorotelomer alcohol (6:2 FTOH) is a common impurity in per- and polyfluoroalkyl substances (PFASs) used in many applications. Our previous toxicokinetic (TK) evaluation of 6:2 FTOH calculated times to steady state (tss) of one of its metabolites, 5:3 fluorotelomer carboxylic acid (5:3A), in the plasma and tissues of up to a year after oral exposure to rats. Our current work further elucidated the TK of 5:3A and other metabolites of 6:2 FTOH in pregnant and nonpregnant rats after repeated oral exposure and examined the role of renal transporters in the biopersistence of 5:3A. The tss values for 5:3A in serum and tissues of adult nonpregnant animals ranged from 150 days to over a year. 4:3 fluorotelomer carboxylic acid (4:3A) was an additional potentially-biopersistent metabolite. 5:3A was the major metabolite of 6:2 FTOH in serum of pregnant dams and fetuses at each time interval. 5:3A was not a substrate for renal transporters in a human kidney cell line in vitro, indicating that renal reuptake of 5:3A is unlikely contribute to its biopersistence. Further research is needed to identify the underlying processes and evaluate the impact of these 6:2 FTOH metabolites on human health.

Abstract 18622: The Role of MicroRNA-98 in the Context of Myocardial Ischemia-Reperfusion Injury During Late Pregnancy

BACKGROUND: We have shown that the late-pregnant (LP) rodent exhibits a higher susceptibility to myocardial ischemia-reperfusion injury (IRI) compared to non-pregnant (NP). The molecular mechanisms remain unclear. The dysregulation of multiple microRNAs (miRs) in IRI suggests their potential as promising targets for therapeutic interventions. Methods: Female Sprague-Dawley rats in both NP and LP states underwent occlusion of the left anterior descending coronary artery (LAD) for a duration of 45 minutes, followed by reperfusion for 3 hours or 24 hours. Expression of miR was assessed via fluorescent in situ hybridization. MicroRNA-microarray profiling was conducted on hearts of NP and LP rats subjected to IRI. Female H9c2 rat cardiomyoblast cells were transfected with miR mimics and inhibitors, and subjected to hypoxia/reoxygenation. Blood samples were obtained from NP, LP, and ischemic heart disease (IHD) patients. MiR98 inhibitor was administered at the initiation of reperfusion. Results: MicroRNA-microarray analysis revealed upregulation of microRNA-98-5p (miR-98) in LV of LP at baseline, and a further upregulation after IRI. The expression of Stat3 and Pgc-1α were decreased in LV of LP rats compared to NP rats upon IRI. Fluorescent in situ hybridization revealed expression of miR-98 in cardiomyocytes in NP rats, which was increased in LP rats. Overexpression of miR-98 in vitro in female H9c2 cells decreased Stat3 and Pgc-1α levels, and promoted apoptosis, oxidative stress, and inflammatory markers. MiR-98 inhibitor in LP rats at the onset of reperfusion reduced infarct size, apoptosis, oxidative stress, and inflammatory markers and was associated with upregulation of Stat3 and Pgc-1α. In humans, plasma miR-98 levels were significantly higher in healthy LP compared to healthy NP individuals and even higher in LP patients with IHD patients. CONCLUSIONS: We show the detrimental effects of miR-98 by promoting cardiomyocyte oxidative stress, inflammation, and apoptosis via its targets Stat3 and Pgc-1α in the context of late pregnancy. MiR-98 could be a novel cardio-protective strategy or biomarker in late pregnancy.