Ovariectomized Rats Research Articles

Antidepressant effects of activation of infralimbic cortex via upregulation of BDNF and β-catenin in an estradiol withdrawal model

RationaleClinical and preclinical studies have demonstrated that estradiol withdrawal after delivery is one of important factors involved in the pathogenesis of postpartum depression (PPD). The infralimbic cortex (IL) is related to anxiety and mood disorders. Whether IL neurons mediate PPD is still unclear.ObjectivesThis study was to observe the antidepressant effect and expression of BDNF and β-catenin in IL by allopregnanolone (ALLO) treatment or the selective activation or inhibition of IL neurons using a chemogenetic approach in a pseudopregnancy model of PPD.MethodsAdministration of estradiol combined with progesterone and the abrupt withdrawal of estradiol simulated the pregnancy and early postpartum periods to induce depression in ovariectomized rats. The relative expression levels of β-catenin and BDNF were observed by western blotting.ResultsImmobility time was significantly increased in the forced swim test and open-arm movement was reduced in the elevated plus maze test in the estradiol-withdrawn rats. After ALLO treatment, the immobility time were lower and open-arm traveling times higher than those of the estradiol-withdrawn rats. Meanwhile, the expression level of BDNF or β-catenin in the IL was reduced significantly in estradiol-withdrawn rats, which was prevented by treatment with ALLO. The hM3Dq chemogenetic activation of pyramidal neurons in the IL reversed the immobility and open-arm travel time trends in the estradiol-withdrawal rat model, but chemogenetic inhibition of IL neurons failed to affect this. Upregulated BDNF and β-catenin expression and increased c-Fos in the basolateral amygdala were found following IL neuron excitation in model rats.ConclusionsOur results demonstrated that pseudopregnancy and estradiol withdrawal produced depressive-like behavior and anxiety. ALLO treatment or specific excitement of IL pyramidal neurons relieved abnormal behaviors and upregulated BDNF and β-catenin expression in the IL in the PPD model, suggesting that hypofunction of IL neurons may be involved in the pathogenesis of PPD.

Effect of antidepressants on bone mineral density and bone metabolism in ovariectomized depressed rats

Purpose: To investigate the effect of antidepressants on bone mineral density and bone metabolism in ovariectomized rats with depression. Methods: 48 female rats were randomly and equally assigned to six groups, namely, sham (Sn), ovariectomized depression (OD), ovariectomized depression rats treated with sertraline (ODs), citalopram (ODx), reboxetine (ODr), and venlafaxine groups (ODw). Behavioral alterations and bone-related parameters were evaluated before and after treatment. Results: After treatment, ODs, ODx, ODw, and ODr groups had higher levels of horizontal and vertical exercise scores, sugar water consumption, osteoclasts, and serum CTX-1 (p < 0.05) compared to OD group. Osteocytes, serum serotonin (5-HT), osteocalcin (BGP), and type I procollagen N-terminal propeptide (PINP) were significantly decreased (p < 0.05) after treatment in ODs, ODx, ODw, and ODr groups. A positive correlation was observed between 5-HT, BGP, PINP, and whole-body bone mineral density (r = 0.931, 0.907, and 0.843, p < 0.05) respectively, while a negative correlation was observed between collagen type I C-terminal propeptide (CTX-I) and bone mineral density (r = -0.855, p < 0.05). Conclusion: Antidepressants reduce bone mineral density and osteocyte proliferation, while increasing osteoclast proliferation. These effects are associated with reductions in 5-HT, PINP and BGP levels, and increase in CTX-I.

Hydrolyzed egg yolk peptide prevented osteoporosis by regulating Wnt/β-catenin signaling pathway in ovariectomized rats

Hydrolyzed egg yolk peptide (YPEP) was shown to increase bone mineral density in ovariectomized rats. However, the underlying mechanism of YPEP on osteoporosis has not been explored. Recent studies have shown that Wnt/β-catenin signaling pathway and gut microbiota may be involved in the regulation of bone metabolism and the progression of osteoporosis. The present study aimed to explore the preventive effect of the YPEP supplementation on osteoporosis in ovariectomized (OVX) rats and to verify whether YPEP can improve osteoporosis by regulating Wnt/β-catenin signaling pathway and gut microbiota. The experiment included five groups: sham surgery group (SHAM), ovariectomy group (OVX), 17-β estradiol group (E2: 25 µg /kg/d 17β-estradiol), OVX with low-dose YPEP group (LYPEP: 10 mg /kg/d YPEP) and OVX with high-dose YPEP group (HYPEP: 40 mg /kg/d YPEP). In this study, all the bone samples used were femurs. Micro-CT analysis revealed improvements in both bone mineral density (BMD) and microstructure by YPEP treatment. The three-point mechanical bending test indicated an enhancement in the biomechanical properties of the YPEP groups. The serum levels of bone alkaline phosphatase (BALP), bone gla protein (BGP), calcium (Ca), and phosphorus (P) were markedly higher in the YPEP groups than in the OVX group. The LYPEP group had markedly lower levels of alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and C-terminal telopeptide of type I collagen (CTX-I) than the OVX group. The YPEP groups had significantly higher protein levels of the Wnt3a, β-catenin, LRP5, RUNX2 and OPG of the Wnt/β-catenin signaling pathway compared with the OVX group. Compared to the OVX group, the ratio of OPG/RANKL was markedly higher in the LYPEP group. At the genus level, there was a significantly increase in relative abundance of Lachnospiraceae_NK4A136_group and a decrease in Escherichia_Shigella in YPEP groups, compared with the OVX group. However, in the correlation analysis, there was no correlation between these two bacteria and bone metabolism and microstructure indexes. These findings demonstrate that YPEP has the potential to improve osteoporosis, and the mechanism may be associated with its modulating effect on Wnt/β-catenin signaling pathway.

Probiotics enhance alveolar bone microarchitecture, intestinal morphology and estradiol levels in osteoporotic animals.

Osteoporosis is associated with bone microarchitecture alterations, and the depletion of estrogen during menopause is a major contributing factor to its development. The literature highlights the noteworthy role of gut microbiota in bone metabolism, particularly in the progression of osteoporosis. Periodontal disease leads to alveolar bone loss, which may be influenced by estrogen deficiency, and this mechanism is intricately associated with an imbalance in systemic microbiota. The aim of this study was to evaluate the effects of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) and Lacticaseibacillus casei 01 (L. casei 01) administrations on an osteoporosis animal model. Thirty-three female rats were randomly divided into three groups: control (C-OVX), C-OVX-HN019 and C-OVX-LC01. All animals were ovariectomized. In groups C-OVX-HN019 and C-OVX-LC01, the probiotics were administered for 4 months. All animals were euthanized after 16 weeks from ovariectomy. Microtomographic, histopathological and immunohistochemical examinations were conducted on periodontal tissues, whereas histomorphometry, histopathological and immunohistochemical analyses were carried out on the intestine. The levels of estradiol were assessed in blood using an immunoenzymatic assay. The data were subjected to statistical analyses (p < .05). The C-OVX-LC01 group exhibited a significant reduction in alveolar bone porosity and an increase in connective tissue density compared to C-OVX (p < .05). The C-OVX-HN019 and C-OVX-LC01 groups presented reduced expression of TRAP and RANKL compared to the C-OVX (p < .05). The C-OVX group presented villi defects, mild neutrophil infiltration, decrease in both villous height and intestinal crypts and reduced expression of intestinal junctional epithelium markers e-cadherin and claudin 01 compared to C-OVX-HN019 and C-OVX-LC01 (p < .05). The C-OVX group had lower estradiol levels than C-OVX-HN019 and C-OVX-LC01 (p < .05). The probiotic therapy promoted a reduction in alveolar bone destruction and intestinal permeability as well as an increase in estradiol levels in ovariectomized rats. Specifically, the probiotic strain Lacticaseibacillus casei 01 exhibited greater effectiveness compared to Bifidobacterium animalis subsp. lactis HN019, indicating strain-dependent outcomes.

Retraction: Improved cognition impairment by activating cannabinoid receptor type 2: Modulating CREB/BDNF expression and impeding TLR-4/NFκBp65/M1 microglia signaling pathway in D-galactose-injected ovariectomized rats.

Retraction: Improved cognition impairment by activating cannabinoid receptor type 2: Modulating CREB/BDNF expression and impeding TLR-4/NFκBp65/M1 microglia signaling pathway in D-galactose-injected ovariectomized rats.

Neferine alleviates ovariectomy-induced osteoporosis by enhancing osteogenic differentiation of bone marrow mesenchymal stem cells via regulation of the p38MAPK pathway

ABSTRACT Objective Osteoporosis, a skeletal ailment marked by bone metabolism imbalance and disruption of bone microarchitecture, Neferine, a bisbenzylisoquinoline alkaloid with diverse pharmacological activities, has received limited attention in the context of osteoporosis treatment. Methods We employed a bilateral ovariectomy (OVX) rat model to induce osteoporosis and subsequently administered Neferine treatment for four weeks following successful model establishment. Throughout the modeling and treatment phases, we closely monitored rat body weights. We assessed alterations in bone tissue microstructure through micro-CT, HE staining, and safranin O-fast green staining. Levels of bone formation and resorption markers in serum were evaluated using ELISA assay. Western blot analysis was employed to determine the expression levels of p38MAPK, p-p38MAPK, and bone formation-related genes in bone tissue. We isolated and cultured OVX rat BMSCs (OVX-BMSCs) and induced osteogenic differentiation while simultaneously introducing Neferine and the p38MAPK inhibitor SB203580 for intervention. Results Neferine treatment effectively curbed the rapid weight gain in OVX rats, ameliorated bone loss, and decreased serum levels of TRAP, CTX-I, PINP, and BALP. Most notably, Neferine promoted the expression of bone formation-related factors in bone tissue of OVX rats, while concurrently activating the p38MAPK signaling pathway. In in vitro experiments, Neferine facilitated the expression of bone formation-related factors in OVX-BMSCs, increased the osteogenic differentiation potential of OVX-BMSCs, and activated the p38MAPK signaling pathway. Nevertheless, SB203580 partially reversed Neferine’s promotive effect. Conclusion Neferine can boost the osteoblastic differentiation of BMSCs and alleviate OVX-induced osteoporosis in rats by activating the p38MAPK signaling pathway.

Abstract PS07-08: Bazedoxifene plus conjugated estrogen reduces mammary proliferation markers and improves adipocyte size, gut microbiome, and metabolic health: Findings from a preclinical model of obesity and breast cancer risk

Abstract Background: Many women at high risk for breast cancer will not take tamoxifen or aromatase inhibitors for cancer prevention due to concern of side effects including hot flashes. Further, tamoxifen has detrimental metabolic effects in some overweight/obese women. Duavee®, a tissue-selective complex of bazedoxifene + conjugated estrogen, is FDA-approved for relief of hot-flashes and prevention of osteoporosis. Preclinical studies suggest favorable metabolic effects and potential for breast cancer risk reduction. In a single arm clinical trial, BZA+CE reduced Ki-67 and mammographic density (PMID: 31420361), and this combination is currently being assessed further in a Phase IIB trial of postmenopausal high risk women with vasomotor symptoms. Here, we examined the modifying effects of obesity on response to BZA+CE in a rodent model of obesity and breast cancer risk. Methods: Rats received carcinogen at 7-weeks of age to induce mammary tumors and were fed a high-fat diet (46% kcal fat) to promote obesity. Lean and obese rat were selected based on adiposity at 16 weeks. Separate cohorts of lean and obese ovary-intact or ovariectomized (OVX) rats were randomized to a daily dose of BZA+CE or placebo control for 8 weeks. We assessed tumor development throughout the study and end of study RNA from mammary glands was analysed by gene expression microarray (Affymetrix). We also analyzed body weight/composition, markers of metabolic health (circulating glucose, insulin, adiponectin), as well as changes in the gut microbiome (metagenomic sequencing on DNA isolated from baseline and end-of-study fecal samples) in response to BZA+CE. Results: BZA+CE improved metabolic health in both ovary intact and OVX rats, including reduced body weight and % body fat, particularly in the visceral regions. These effects were greater in obese rats compared to lean. BZA+CE reduced the number of large adipocytes and increased small (insulin sensitive) adipocytes in the mammary adipose, indicating benefical changes in local tumor microenvironment. We found no evidence that Duavee® promoted tumor development or growth in ovary-intact or OVX’d rats. Gene set enrichment analysis (GSEA) of microarray data showed enrichment of cell proliferation pathways in MG from obese rats and these same pathways were downregulated with BZA+CE, consistent with anti-cancer effects. Analysis of the microbiome found that BZA+CE increased proportional abudance of Odoribacter laneus in the gut, regardless of lean/obese or intact/OVX status. Previous studies have demonstrated that this bacterim improves glucose control and reduces inflammatory cytokines when administered to obese mice, suggesting a possible mechanistic link in this study. Conclusions: Unlike traditional SERMs that can have negative metabolic effects, BZA+CE improved whole body and mammary gland metabolic health and reduced expression of cell proliferation pathways, particularly in obese rats. Prelminary data suggest that changes in the gut microbiome could contribute, at least in part, to these effects. Together this supports BZA+CE (Duavee) as an agent with potential beneficial effects on breast cancer risk reduction and improvements in metabolic health in women with obesity. Further analyses will guide assessment of outcomes in an ongoing parallel clinical study in postmenopausal women at high risk for breast cancer. Citation Format: Katherine L. Cook, Ramsey Jenshcke, Karen Corleto, Carol Fabian, Stephen Hursting, Bruce Kimler, Danilo Landrock, Erin Giles. Bazedoxifene plus conjugated estrogen reduces mammary proliferation markers and improves adipocyte size, gut microbiome, and metabolic health: Findings from a preclinical model of obesity and breast cancer risk [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS07-08.

Development of Transdermal Formulation Based on Nanotechnology and Elucidation of Its Drug Delivery Pathways

Transdermal drug delivery is a formulation in which the drug is absorbed through the skin for systemic action. Its advantages include avoidance of first-pass effects, sustained drug supply, and ease of administration and discontinuation. Drugs administered transdermally transfer into the blood circulation through the stratum corneum, epidermis, and dermis. The stratum corneum on the skin surface plays a barrier function in skin absorption. Therefore, developing of transdermal drug delivery systems requires innovations that overcome the barrier function of the stratum corneum and improve skin permeation. This review examines the usefulness of transdermal formulations based on solid nanoparticles using raloxifene. Milled raloxifene was gelled with (mRal-NPs) or without menthol (Ral-NPs) using Carbopol. The drug release and transdermal penetration were measured using a Franz diffusion cell, and the therapeutic evaluation of osteoporosis was determined in an ovariectomized rat model. Although the raloxifene released from Ral-NPs remained in the nanoparticle state, the skin penetration of raloxifene nanoparticles was prevented by the stratum corneum in rat. The inclusion of menthol in the formulation attenuated the barrier function of the stratum corneum and permitted raloxifene nanoparticles to penetrate through the skin. Moreover, macropinocytosis relates to the formulation's skin penetration, including menthol (mRal-NPs). Applying mRal-NPs attenuated the decreases in calcium level and stiffness of bones of ovariectomized rats. This information can support future studies aimed at designing novel transdermal formulations.

Calcium-fortified fresh milk ameliorates postmenopausal osteoporosis via regulation of bone metabolism and gut microbiota in ovariectomized rats

The aging of the global population has made postmenopausal osteoporosis prevention essential; however, pharmacological treatments are limited. Herein, we evaluate the effect of calcium-fortified fresh milk (FM) in ameliorating postmenopausal osteoporosis in a rat model established using bilateral ovariectomy. After 3 months of FM (containing vitamin D, and casein phosphopeptides, 1000 mg Ca/100 g) or control milk (110 mg Ca/100 g milk) supplementation, bone changes were assessed using dual-energy X-ray absorptiometry, microcomputed tomography, and bone biomechanical testing. The results revealed that FM can regulate bone metabolism and gut microbiota composition, which act on bone metabolism through pathways associated with steroid hormone biosynthesis, relaxin signaling, serotonergic synapse, and unsaturated fatty acid biosynthesis. Furthermore, FM administration significantly increased bone mineral content and density in the lumbar spine and femur, as well as femoral compressive strength, while improving femoral trabecular bone parameters and microarchitecture. Mechanistically, we found that the effects may be due to increased levels of estrogen, bone formation marker osteocalcin, and procollagen type I N-propeptide, and decreased expression of the bone resorption marker C-telopeptide and tartrate-resistant acid phosphatase 5b. Overall, the findings suggest that FM is a potential alternative therapeutic option for ameliorating postmenopausal osteoporosis.

Estrogens and Olfactomedins May Induce a Feedback Loop that Increases Nicotine Consumption in Females via the Brain Reward Circuitry

Estrogen is associated with enhanced nicotine use in women, with enhanced vulnerability to nicotine use disorders being associated with higher levels of circulating estrogen. In ovariectomized (OVX) female rats, estradiol (E2) treatments increased estrogen receptor β (ERβ) and not ERα in a key brain reward region, the nucleus accumbens core (NAcore). Therefore, we hypothesized that ERβ might be important in the reward circuitry for regulating nicotine use in females. To determine ERβ-specific functions that might regulate nicotine use, we analyzed large sequencing datasets of estrogen-induced genes and narrowed the list to those expressed in the brain and that have a hormone function. We found one class of genes known as the olfactomedins (OLFMs), which meet these criteria. Therefore, we wanted to determine whether ERα or ERβ regulates the expression of the OLFM isoforms. We used human uterine cells (Ishikawa) that express both ER isoforms and the OLFMs and found that two-hour E2 treatments induced the expression of OLFM1 and OLFM3. However, nicotine only suppressed the E2-induction of OLFM1 and not the others. We next performed chromatin immunoprecipitation (ChIP) assays with these cells and treatments using antibodies for ERα, ERβ, or GFP control. We found that the OLFM1 promoter was only enriched by ERβ, and no binding of ERα was observed. We next treated OVX female rats with E2, nicotine, E2+nicotine, or vehicle and found that Olfm1 and Olfm2 significantly increased in the NAcore, and all three OLFM isoforms were significantly higher in the ventral tegmental area (VTA), another key region within the mesolimbic reward pathway. Nicotine suppressed the E2-induced OLFM expression in the NAcore and VTA. These new findings suggest that ERβ-induction of the olfactomedins might serve as a feedback loop for driving nicotine addiction processes, which is suppressed when nicotine is on board. These results indicate a potential new target for therapeutic cessation of nicotine use in women. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Assessing the effects of probiotic supplementation, single strain versus mixed strains, on femoral mineral density and osteoblastic gene mRNA expression in rats.

Osteoporosis is a significant health concern characterized by weak and porous bones, particularly affecting menopausal women aged 50 and above, leading to increased risk of hip fractures and associated morbidity and mortality. We conducted a study to assess the efficacy of single-strain versus mixed-strain probiotic supplementation on bone health using an ovariectomy (OVX) rat model of induced bone loss. The probiotics evaluated were Lactobacillus helveticus (L. helveticus), Bifidobacterium longum (B. longum), and a combination of both. Rats were divided into five groups: SHAM (Control negative), OVX (Control positive), OVX +L. helveticus, OVX + B. longum, and OVX + mixed L. helveticus and B. longum. Daily oral administration of probiotics at 10^8-10^9 CFU/mL began two weeks post-surgery and continued for 16 weeks. Both single-strain and mixed-strain probiotic supplementation upregulated expression of osteoblastic genes (BMP- 2, RUNX-2, OSX), increased serum osteocalcin (OC) levels, and improved bone formation parameters. Serum C-terminal telopeptide (CTX) levels and bone resorption parameters were reduced. However, the single-strain supplementation demonstrated superior efficacy compared to the mixed-strain approach. Supplementation with B. longum and L. helveticus significantly reduces bone resorption and improves bone health in OVX rats, with single-strain supplementation showing greater efficacy compared to a mixed-strain combination. These findings highlight the potential of probiotics as a therapeutic intervention for osteoporosis, warranting further investigation in human studies.

Low-Intensity Extracorporeal Shock Wave Therapy Ameliorates Detrusor Hyperactivity with Impaired Contractility via Transient Potential Vanilloid Channels: A Rat Model for Ovarian Hormone Deficiency.

This study explores low-intensity extracorporeal shock wave therapy (LiESWT)'s efficacy in alleviating detrusor hyperactivity with impaired contractility (DHIC) induced by ovarian hormone deficiency (OHD) in ovariectomized rats. The rats were categorized into the following four groups: sham group; OVX group, subjected to bilateral ovariectomy (OVX) for 12 months to induce OHD; OVX + SW4 group, underwent OHD for 12 months followed by 4 weeks of weekly LiESWT; and OVX + SW8 group, underwent OHD for 12 months followed by 8 weeks of weekly LiESWT. Cystometrogram studies and voiding behavior tracing were used to identify the symptoms of DHIC. Muscle strip contractility was evaluated through electrical-field, carbachol, ATP, and KCl stimulations. Western blot and immunofluorescence analyses were performed to assess the expressions of various markers related to bladder dysfunction. The OVX rats exhibited significant bladder deterioration and overactivity, alleviated by LiESWT. LiESWT modified transient receptor potential vanilloid (TRPV) channel expression, regulating calcium concentration and enhancing bladder capacity. It also elevated endoplasmic reticulum (ER) stress proteins, influencing ER-related Ca2+ channels and receptors to modulate detrusor muscle contractility. OHD after 12 months led to neuronal degeneration and reduced TRPV1 and TRPV4 channel activation. LiESWT demonstrated potential in enhancing angiogenic remodeling, neurogenesis, and receptor response, ameliorating DHIC via TRPV channels and cellular signaling in the OHD-induced DHIC rat model.

Estradiol modulates the role of the spinal α6-subunit containing GABAA receptors in female rats with neuropathic pain

The purpose of this study was to investigate the mechanisms underlying sex differences in the role of spinal α6-subunit containing GABAA (α6GABAA) receptors in rats with neuropathic pain. Intrathecal 2,5-dihydro-7-methoxy-2-(4-methoxyphenyl)-3H-pyrazolo [4,3-c] quinoline-3-one (PZ-II-029, positive allosteric modulator of α6GABAA receptors) reduced tactile allodynia in female but not in male rats with neuropathic pain. PZ-II-029 was also more effective in females than males in inflammatory and nociplastic pain. Ovariectomy abated the antiallodynic effect of PZ-II-029 in neuropathic rats, whereas 17β-estradiol or 4,4′,4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT), estradiol receptor-α agonist, restored the effect of PZ-II-029 in ovariectomized rats. Blockade of estradiol receptor-α, using MPP (1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy) phenol]-1H-pyrazole dihydrochloride), prevented the effect of 17β-estradiol on PZ-II-029-induced antiallodynia in ovariectomized neuropathic females. Nerve injury reduced α6GABAA receptor protein expression at the dorsal root ganglia (DRG) and spinal cord of intact and ovariectomized female rats. In this last group, reconstitution with 17β-estradiol fully restored its expression in DRG and spinal cord. In male rats, nerve injury reduced α6GABAA receptor protein expression only at the spinal cord. Nerve injury enhanced estradiol receptor-α protein expression at the DRG in intact non-ovariectomized rats. However, ovariectomy decreased estradiol receptor-α protein expression at the DRG. In the spinal cord there were no changes in estradiol receptor-α protein expression. 17β-estradiol restored estradiol receptor-α protein expression at the DRG and increased it at the spinal cord of neuropathic rats. These data suggest that 17β-estradiol modulates the expression and function of the α6GABAA receptor through its interaction with estradiol receptor-α in female rats.

UPLC-Triple-TOF-MS-based serum metabonomic revealed the alleviating effect of QingYan Formula on perimenopausal syndrome rats

The study aimed to investigate the relieving effect of QingYan Formula (QYF) in treating perimenopausal syndrome. A combination of metabonomic analysis and in vitro pharmacodynamic experiments was employed to achieve this objective.Over a period of 12 weeks, ovariectomized (OVX) rats were orally administered QYF's 70 % ethanol extract or estradiol valerate (EV). The results demonstrate that QYF restored the estrous cycle of ovariectomized rats and exhibited significant estrogenic activity, as indicated by reversal of uterine and vagina atrophy, improvement of serum estradiol level and decrease of serum luteinizing hormone(LH) level. Additionally, QYF administration effectively reduced high bone turnover and repaired trabecular microstructure damage. Metabonomic analysis of the OVX rats treated with QYF revealed the identification of 55 different metabolites in the serum, out of which 35 may be potential biomarkers. QYF could regulate the disturbed metabolic pathways including the Biosynthesis of unsaturated fatty acids, arachidonic acid metabolism, bile secretion, and steroid hormone biosynthesis. PI3KCA, SRC, and MAPK3 are potential therapeutic targets for QYF therapeutic effects. These findings support the efficacy of QYF in alleviating perimenopausal syndrome and regulating lipid metabolic disorders in OVX rats.

Synergistic neuroprotective action of prolactin and 17β-estradiol on kainic acid-induced hippocampal injury and long-term memory deficit in ovariectomized rats.

The neuroprotective actions of the ovarian hormone 17β-estradiol (E2) against different brain lesions have been constantly confirmed in a variety of models including kainic acid (KA) lesions. Similarly, the pituitary hormone prolactin (PRL), traditionally associated with lactogenesis, has recently been linked to a large diversity of functions, including neurogenesis, neuroprotection, and cognitive processes. While the mechanisms of actions of E2 as regards its neuroprotective and behavioral effects have been extensively explored, the molecular mechanisms of PRL related to these roles remain under investigation. The current study aimed to investigate whether the simultaneous administration of PRL and a low dose of E2 prevents the KA-induced cognitive deficit and if this action is associated with changes in hippocampal neuronal density. Ovariectomized (OVX) rats were treated with saline, PRL, and/or E2 in the presence or absence of KA. Neuroprotection was assessed by Nissl staining and neuron counting. Memory was evaluated with the novel object recognition test (NOR). On their own, both PRL and E2 prevented short- and long-term memory deficits in lesioned animals and exerted neuroprotection against KA-induced excitotoxicity in the hippocampus. Interestingly, the combined hormonal treatment was superior to either of the treatments administered alone as regards improving both memory and neuronal survival. Taken together, these results point to a synergic effect of E2 and PRL in the hippocampus to produce their behavioral, proliferative, and neuroprotective effects.

Astaxanthin prevents bone loss in osteoporotic rats with palmitic acid through suppressing oxidative stress

ABSTRACT Objectives The study aimed to assess the role of Astaxanthin (ATX) in palmitic acid(PA) -induced bone loss in Ovariectomized(OVX) rats. Methods In the OVX rat model, we observed that PA affects bone metabolism and accelerates bone loss. Additionally, treatment with ATX was able to suppress the deleterious effects of PA and a simultaneous decrease in serum MDA levels and an increase in SOD was observed. Results In addition, rats treated with ATX were observed to have significantly increased bone mass and elevated activity of SIRT1 and SOD2 in bone tissue. When MC3T3-E1 and RAW264.7 cells induced osteoblast and osteoclast differentiation, the ATX intervention was able to significantly restore the restriction of osteogenic differentiation and the up-regulation of osteoclast differentiation with PA therapy. Furthermore, we confirm that PA damage to cells is caused by increased oxidative stress, and that ATX can target and modulate the activity of SIRT1 to regulate the levels of oxidative stress in cells. Conclusion Summarizing, ATX may inhibit PA-induced bone loss through its antioxidant properties via the SIRT1 signaling pathway.

Mijiao formula regulates NAT10-mediated Runx2 mRNA ac4C modification to promote bone marrow mesenchymal stem cell osteogenic differentiation and improve osteoporosis in ovariectomized rats

Ethnopharmacological relevanceThe Mijiao (MJ) formula, a traditional herbal remedy, incorporates antlers as its primary constituent. It can effectively treat osteoporosis (OP), anti-aging, enhance immune activity, and change depression-like behavior. In this study, we investigated that MJ formula is a comprehensive treatment strategy, and may provide a potential approach for the clinical treatment of postmenopausal osteoporosis. Aim of the studyThe purpose of this study was to determine whether MJ formula promoted osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and improved osteoporosis in ovariectomized rats by regulating the NAT10-mediated Runx2 mRNA ac4C modification. Materials and methodsFemale Sprague-Dawley (SD) rats were used to investigate the potential therapeutic effect of MJ formula on OP by creating an ovariectomized (OVX) rat model. The expression of osteogenic differentiation related proteins in BMSCs was detected in vivo, indicating their role in promoting bone formation. In addition, the potential mechanism of its bone protective effect was explored via in vitro experiments. ResultsOur study showed that MJ formula significantly mitigated bone mass loss in the OVX rat model, highlighting its potential as an OP therapeutic agent. We found that the possible mechanism of action was the ability of this formulation to stabilize Runx2 mRNA through NAT10-mediated ac4C acetylation, which promoted osteogenic differentiation of BMSCs and contributed to the enhancement of bone formation. ConclusionsMJ formula can treat estrogen deficiency OP by stabilizing Runx2 mRNA, promoting osteogenic differentiation and protecting bone mass. Conceivably, MJ formulation could be a safe and promising strategy for the treatment of osteoporosis.

The novel small molecule E0924G dually regulates bone formation and bone resorption through activating the PPARδ signaling pathway to prevent bone loss in ovariectomized rats and senile mice

Osteoporosis is particularly prevalent among postmenopausal women and the elderly. In the present study, we investigated the effect of the novel small molecule E0924G (N-(4-methoxy-pyridine-2-yl)-5-methylfuran-2-formamide) on osteoporosis. E0924G significantly increased the protein expression levels of osteoprotegerin (OPG) and runt-related transcription factor 2 (RUNX2), and thus significantly promoted osteogenesis in MC3T3-E1 cells. E0924G also significantly decreased osteoclast differentiation and inhibited bone resorption and F-actin ring formation in receptor activator of NF-κB ligand (RANKL)-induced osteoclasts from RAW264.7 macrophages. Importantly, oral administration of E0924G in both ovariectomized (OVX) rats and SAMP6 senile mice significantly increased bone mineral density and decreased bone loss compared to OVX controls or SAMR1 mice. Further mechanistic studies showed that E0924G could bind to and then activate peroxisome proliferator-activated receptor delta (PPARδ), and the pro-osteoblast effect and the inhibition of osteoclast differentiation induced by E0924G were significantly abolished when PPARδ was knocked down or inhibited. In conclusion, these data strongly suggest that E0924G has the potential to prevent OVX-induced and age-related osteoporosis by dual regulation of bone formation and bone resorption through activation of the PPARδ signaling pathway.

Eldecalcitol Induces Minimodeling-Based Bone Formation and Inhibits Sclerostin Synthesis Preferentially in the Epiphyses Rather than the Metaphyses of the Long Bones in Rats.

This study aimed to examine minimodeling-based bone formation between the epiphyses and metaphyses of the long bones of eldecalcitol (ELD)-administered ovariectomized rats. Sixteen-week-old female rats were divided into four groups: sham-operated rats receiving vehicle (Sham group), ovariectomized (OVX) rats receiving vehicle (Vehicle group), or ELDs (30 or 90 ng/kg BW, respectively; ELD30 and ELD90 groups). ELD administration increased bone volume and trabecular thickness, reducing the number of osteoclasts in both the epiphyses and metaphyses of OVX rats. The Sham and Vehicle groups exhibited mainly remodeling-based bone formation in both regions. The epiphyses of the ELD groups showed a significantly higher frequency of minimodeling-based bone formation than remodeling-based bone formation. In contrast, the metaphyses exhibited significantly more minimodeling-based bone formation in the ELD90 group compared with the ELD30 group. However, there was no significant difference between minimodeling-based bone formation and remodeling-based bone formation in the ELD90 group. While the minimodeling-induced new bone contained few sclerostin-immunoreactive osteocytes, the underlying pre-existing bone harbored many. The percentage of sclerostin-positive osteocytes was significantly reduced in the minimodeling-induced bone in the epiphyses but not in the metaphyses of the ELD groups. Thus, it seems likely that ELD could induce minimodeling-based bone formation in the epiphyses rather than in the metaphyses, and that ELD-driven minimodeling may be associated with the inhibition of sclerostin synthesis.

Effect of silver nanoparticles formulated by Silybum marianum on menopausal urinary incontinence in ovariectomized rats

Abstract Urinary incontinence is the major sign of menopause genitourinary syndrome and is usually related to the sexual dysfunctions. Fifty percent of menopausal women have menopausal urinary tract. Menopause genitourinary syndrome is a hypoestrogenic condition with external sexual, urological, and genital implications. The production of estrogen decline after menopause is an important parameter for urinary incontinence. Recently, nanotechnology has been applied as a remedial option for the genitourinary disease treatment. Silver nanoparticles were mediated by the Silybum marianum aqueous extract for the menopausal urinary incontinence treatment in ovariectomized rats in the current experiment. The green-formulated AgNPs@Silybum marianum were characterized by FT-IR, TEM, SEM, and UV–Vis. The SEM findings prove the spherical morphology with size of 15–60 nm. The ovariectomized rats were treated by AgNPs@Silybum marianum (5 and 20 µg/kg/day) for 56 days. According to the results, AgNPs@Silybum marianum increased the urinary bladder weight and reduced the body weights in comparison with the untreated rats. AgNPs@Silybum marianum rats indicated a dose-dependent amelioration for the acetylcholine contraction index. AgNPs@Silybum marianum also ameliorated the levels of serum 17β-estradiol, urinary bladder hydroxyproline, triglyceride, cholesterol, LDL, HDL, ALP, AST, and ALT in the ovariectomized rats. Based on the experiment results, the recent formulation may be applied for the menopausal urinary incontinence treatment in humans after performing the clinical research.