OBJECTIVE: To initially investigate the function of neuronal pentraxin 1 (NPTX1) gene on osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). METHODS: hBMSCs were induced to undergo osteogenic differentiation, and then RNA was collected at different time points, namely 0, 3, 7, 10 and 14 d. The mRNA expression levels of key genes related with osteogenic differentiation, including runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN), and NPTX1, were detected on the basis of quantitative real-time polymerase chain reaction (qPCR) technology. In order to establish a stable NPTX1-knockdown hBMSCs cell line, NPTX1 shRNA lentivirus was constructed and used to infect hBMSCs. ALP staining, alizarin red (AR) staining, and qPCR were employed to assess the impact of NPTX1-knockdown on the osteogenic differentiation ability of hBMSCs. RESULTS: The results showed that during the osteogenic differentiation of hBMSCs in vitro, the mRNA expression levels of osteogenic genes RUNX2, ALP and OCN significantly increased compared with 0 d, while NPTX1 expression decreased markedly (P < 0.01) as the osteogenic induction period exten-ded. At 72 h post-infection with lentivirus, the result of qPCR indicated that the knockdown efficiency of NPTX1 was over 60%. After knocking down NPTX1 in hBMSCs, RNA was extracted from both the NPTX1-knockdown group (sh NPTX1 group) and the control group (shNC group) cultured in regular proliferation medium. The results of qPCR showed that the expression levels of osteogenic-related genes RUNX2 and osterix (OSX) were significantly higher in the sh NPTX1 group compared with the shNC group (P < 0.01). ALP staining revealed a significantly deeper coloration in the sh NPTX1 group than in the shNC group at the end of 7 d of osteogenic induction. AR staining demonstrated a marked increase in mineralized nodules in the sh NPTX1 group compared with the shNC group at the end of 14 d of osteogenic induction. CONCLUSION NPTX1 exerts a modulatory role in the osteogenic differentiation of hBMSCs, and its knockdown has been found to enhance the osteogenic differentiation of hBMSCs. This finding implies that NPTX1 could potentially serve as a therapeutic target for the treatment of osteogenic abnormalities, including osteoporosis.
Humans ; Mesenchymal Stem Cells/cytology* ; Osteogenesis/genetics* ; Cell Differentiation/genetics* ; Nerve Tissue Proteins/genetics* ; Cells, Cultured ; C-Reactive Protein/genetics* ; RNA, Small Interfering/genetics* ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Bone Marrow Cells/cytology* ; Gene Knockdown Techniques ; Osteocalcin/metabolism* ; Alkaline Phosphatase/metabolism* ; RNA, Messenger/metabolism*

OBJECTIVE: To investigate the effect of human adipose-derived mesenchymal stem cells (hASCs) exosomes on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) extracted from osteoporotic mice, and to evaluate the effect of hASCs exosomes on preventing bone loss induced by estrogen deficiency. METHODS: hASCs exosomes were extracted by ultracentrifugation. The osteoporotic mice were established by bilateral ovariectomy (OVX). BMSCs were isolated from osteo-porotic mice and cultured for further analysis. In the experimental group, these BMSCs were exposed to an osteogenic induction medium supplemented with hASCs exosomes to evaluate their potential effects on osteogenesis. In contrast, the control group was treated with the same osteogenic induction medium, but without the addition of hASCs exosomes, to serve as a baseline comparison for the study. To comprehensively assess the osteogenic differentiation of BMSCs influenced by hASCs exosomes, alkaline phosphatase (ALP) staining, ALP activity quantitative analysis and quantitative reverse transcription polymerase chain reaction (qPCR) were performed. These evaluations provided critical insights into the role of hASCs exosomes in promoting osteoblast differentiation and bone formation in osteoporotic conditions. The fluorescence labeled hASCs exosomes were injected via the tail vein to observe the biodistribution of exosomes. Two weeks after OVX, the mice were divided into three groups: The experimental group consisted of estrogen-deficient mice receiving hASCs exosome injections; the negative control group consisted of estrogen-deficient mice receiving phosphate-buffered saline (PBS) injections; and the positive control group consisted of mice that underwent Sham surgery and received PBS injections.The injections were administered once every 3 days, for a total of 8 injections. Afterward, the femurs were collected from the mice, and micro-computed tomography (micro-CT) was performed to measure bone mineral density and conduct bone morphometric analysis. RESULTS: hASCs exosomes were successfully extracted using ultracentrifugation. After the induction by hASCs exosomes, ALP staining and ALP activity in the BMSCs extracted from osteoporotic mice were significantly enhanced, the expression of osteogenesis related genes in BMSCs were significantly up-regulated. More trabecular bone and higher bone mineral density were observed in estrogen-deficient mice injected with hASCs exosomes compared with estrogen-deficient mice injected with PBS, and there was no significant decrease in bone mineral density compared with the Sham operation group. CONCLUSION hASCs exosomes promoted the osteogenic differentiation of BMSCs extracted from osteoporotic mice. hASCs exosomes prevented bone loss induced by estrogen deficiency.
Animals ; Mesenchymal Stem Cells/cytology* ; Exosomes ; Estrogens/deficiency* ; Humans ; Osteogenesis ; Cell Differentiation ; Female ; Mice ; Osteoporosis/prevention & control* ; Ovariectomy ; Adipose Tissue/cytology* ; Cells, Cultured

OBJECTIVE: To identify the role of gene silencing or overexpression of Nemo-like kinase (NLK) during the process of neural differentiation of human mesenchymal stem cells (hBMSCs), and to explore the effect of NLK downregulation by transfection of small interfering RNA (siRNA) on promoting neuralized tissue engineered bone regeneration. METHODS: NLK-knockdown hBMSCs were established by transfection of siRNA (the experimental group was transfected with siRNA silencing the NLK gene, the control group was transfected with control siRNA and labeled as negative control group), and NLK-overexpression hBMSCs were established using lentivirus vector transfection technique (the experimental group was infected with lentivirus overexpressing the NLK gene, the control group was infected with an empty vector lentivirus and labeled as the empty vector group). After neurogenic induction, quantitative real-time polymerase chain reaction (qPCR) was used to detect the expression of neural-related gene, and Western blot as well as immunofluorescence staining about several specific neural markers were used to evaluate the neural differentiation ability of hBMSCs.6-week-old male nude mice were divided into 4 groups: ① β-tricalcium phosphate (β-TCP) group, ② β-TCP+ osteogenic induced hBMSCs group, ③ β-TCP+ siRNA-negative control (siRNA-NC) transfection hBMSCs group, ④ β-TCP+ siRNA-NLK transfection hBMSCs group. Four weeks after the subcutaneous ectopic osteogenesis models were established, the osteogenesis and neurogenesis were detected by hematoxylin-eosin (HE) staining, Masson staining and tissue immunofluorescence assay. Statistical analysis was conducted by independent sample t test. RESULTS: After gene silencing of NLK by siRNA in hBMSCs, neural-related genes, including the class Ⅲ β-tubulin (TUBB3), microtubule association protein-2 (MAP2), soluble protein-100 (S100), nestin (NES), NG2 proteoglycan (NG2) and calcitonin gene-related peptide (CGRP), were increased significantly in NLK-knockdown hBMSCs compared with the negative control group(P < 0.05), and the expression levels of TUBB3 and MAP2 of the NLK silencing group were also increased. Oppositely, after NLK was overexpressed using lentivirus vector transfection technique, TUBB3, MAP2, S100 and NG2 were significantly decreased in NLK-overexpression hBMSCs compared with the empty vector group (P < 0.05), and the expression level of TUBB3 was also decreased. 4 weeks after the subcutaneous ectopic osteogenesis model was established, more mineralized tissues were formed in the β-TCP+ siRNA-NLK transfection hBMSCs group compared with the other three groups, and the expression of BMP2 and S100 was higher in the β-TCP+ siRNA-NLK transfection hBMSCs group than in the other groups. CONCLUSION Gene silencing of NLK by siRNA promoted the ability of neural differentiation of hBMSCs in vitro and promoted neuralized tissue engineered bone formation in subcutaneous ectopic osteogenic models in vivo in nude mice.
Bone Regeneration/genetics* ; Animals ; Mesenchymal Stem Cells/cytology* ; Humans ; RNA, Small Interfering/genetics* ; Tissue Engineering/methods* ; Cell Differentiation ; Mice, Nude ; Gene Silencing ; Mice ; Male ; Protein Serine-Threonine Kinases/genetics* ; Intracellular Signaling Peptides and Proteins/genetics* ; Transfection ; Cells, Cultured ; Lentivirus/genetics*

OBJECTIVE: To investigate the biocompatibility of porous WE43 magnesium alloy scaffolds manufactured by 3D printing technology and to observe its effect in treating femoral defects in New Zealand white rabbits. METHODS: In vitro cytotoxicity test was performed using bone marrow mesenchymal stem cells from Sprague Dawley (S-D) rats. According to the different culture media, the cells were divided into 100% extract group, 50% extract group, 10% extract group and control group. After culturing for 1, 3 and 7 days, the cell activity of each group was determined by cell counting kit-8 (CCK-8). In the in vivo experiment, 3.0-3.5 kg New Zealand white rabbits were randomly divided into three groups: Experimental group, bone cement group and blank group, with 9 rabbits in each group. Each rabbit underwent surgery on the left lateral femoral condyle, and a bone defect with a diameter of 5 mm and a depth of 6 mm was created using a bone drill. The experimental group was implanted with WE43 magnesium alloy scaffolds, the bone cement group was implanted with calcium sulfate bone cement, and the blank group was not implanted. Then 4, 8 and 12 weeks after surgery, 3 rabbits in each group were euthanized by carbon dioxide anesthesia, and the femur and important internal organs were sampled. Micro-computed tomography (Micro-CT) scanning was performed on the left lateral femoral condyle. Sections of important internal organs were prepared and stained with hematoxylin-eosin (HE). Hard tissue sections were made from the left lateral femoral condyle and stained with methylene blue acid fuchsin and observed under a microscope. RESULTS: In the cytotoxicity test, the cell survival rate in the 100% extract group was higher than that in the control group (140.56% vs. 100.00%, P < 0.05) on 1 day of culture; there was no statistically significant difference (P>0.05) in cell survival rate among the groups on 3 days of culture; the cell survival rate in the 100% extract group was lower than that in the control group (68.64% vs. 100.00%, P < 0.05) on 7 days of culture. Micro-CT scanning in the in vivo experiment found that most of the scaffolds in the experimental group had been degraded in 4 weeks, with very few high-density scaffolds remaining. In 12 weeks, there was no obvious stent outline. In 4 weeks, a certain amount of gas was generated around the WE43 magnesium alloy scaffold, and the gas was significantly reduced from 8 to 12 weeks. Hard tissue sections showed that a certain amount of extracellular matrix and osteoid were generated around the scaffolds in the experimental group in 4 weeks. In the bone cement group, most of the calcium sulfate bone cement had been degraded. In 8 weeks, the osteoid around the scaffold and its degradation products in the experimental group increased significantly. In 12 weeks, new bone was in contact with the scaffold around the scaffold in the experimental group. There was less new bone in the bone cement group and the blank group. CONCLUSION The porous WE43 magnesium alloy scaffold fabricated by 3D printing process has good biocompatibility and good osteogenic properties, and has the potential to become a new material for repairing bone defects.
Animals ; Rabbits ; Printing, Three-Dimensional ; Alloys/chemistry* ; Tissue Scaffolds/chemistry* ; Magnesium/chemistry* ; Rats, Sprague-Dawley ; Biocompatible Materials ; Mesenchymal Stem Cells/cytology* ; Femur/surgery* ; Rats ; Absorbable Implants ; Male ; Bone Regeneration ; Tissue Engineering/methods* ; Cells, Cultured

Dental stem cells (DSCs), a distinct subset of mesenchymal stem cells (MSCs), are isolated from dental tissues, such as dental pulp, exfoliated deciduous teeth, periodontal ligament, and apical papilla. They have emerged as a promising source of stem cell therapy for tissue regeneration and autoimmune disorders. The main types of DSCs include dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), and stem cells from apical papilla (SCAP). Each type exhibits distinct advantages: easy access via minimally invasive procedures, multi-lineage differentiation potential, and excellent ethical acceptability. DSCs have demonstrated outstanding clinical efficacy in oral and maxillofacial regeneration, and their long-term safety has been verified. In oral tissue regeneration, DSCs are highly effective in oral tissue regeneration for critical applications such as the restoration of dental pulp vitality and periodontal tissue repair. A defining advantage of DSCs lies in their ability to integrate with host tissues and promote physiological regeneration, which render them a better option for oral tissue regenerative therapies. Beyond oral applications, DSCs also exhibit promising potential in the treatment of systemic diseases, including type Ⅱ diabetes and autoimmune diseases due to their immunomodulatory effects. Moreover, extracellular vesicles (EVs) derived from DSCs act as critical mediators for DSCs' paracrine functions. Possessing regulatory properties similar to their parental cells, EVs are extensively utilized in research targeting tissue repair, immunomodulation, and regenerative therapy-offering a "cell-free" strategy to mitigate the limitations associated with cell-based therapies. Despite these advancements, standardizing large-scale manufacturing, maintaining strict quality control, and clarifying the molecular mechanisms underlying the interaction of DSCs and their EVs with recipient tissues remain major obstacles to the clinical translation of these treatments into broad clinical use. Addressing these barriers will be critical to enhancing their clinical applicability and therapeutic efficacy. In conclusion, DSCs and their EVs represent a transformative approach in regenerative medicine, and increasing clinical evidence supports their application in oral and systemic diseases. Continuous innovation remains essential to unlocking the widespread clinical potential of DSCs.
Humans ; Dental Pulp/cytology* ; Translational Research, Biomedical ; Mesenchymal Stem Cells/cytology* ; Periodontal Ligament/cytology* ; Stem Cells/cytology* ; Regeneration ; Tooth, Deciduous/cytology* ; Cell Differentiation ; Tissue Engineering/methods* ; Regenerative Medicine

The prevalence of periodontitis in China is as high as 74.2%, making it the leading cause of tooth loss in adults and severely impacting both oral and overall health. The treatment of periodontitis and periodontal tissue regeneration are global challenges of significant concern. GE Shaohua' s group at School and Hospital of Stomatology, Shandong University has focused on the key scientific issue of "remodeling the periodontal inflammatory microenvironment and optimizing tissue repair and regeneration". They have elucidated the mechanisms underlying the persistence of periodontitis, developed bioactive materials to enhance stem cell regenerative properties, and constructed a series of guided tissue regeneration barrier membranes to promote periodontal tissue repair, leading to the establishment of a comprehensive technology system for the treatment of periodontitis. Specific achievements and progress include: (1) Elucidating the mechanism by which key periodontal pathogens evade antimicrobial autophagy, leading to inflammatory damage; developing intelligent antimicrobial hydrogels and nanosystems, and creating metal-polyphenol network microsphere capsules to reshape the periodontal inflammatory microenvironment; (2) Explaining the mechanisms by which nanomaterial structures and electroactive interfaces regulate stem cell behavior, developing optimized nanostructures and electroactive biomaterials, thereby effectively enhancing the regenerative repair capabilities of stem cells; (3) Creating a series of biphasic heterogeneous barrier membranes, refining guided tissue regeneration and in situ tissue engineering techniques, stimulating the body' s intrinsic repair potential, and synergistically promoting the structural regeneration and functional reconstruction of periodontal tissues. The research outcomes of the group have innovated the fundamental theories of periodontal tissue regeneration, broken through foreign technological barriers and patent blockades, established a cascade repair strategy for periodontal regeneration, and enhanced China' s core competitiveness in the field of periodontal tissue regeneration.
Humans ; Stem Cells/physiology* ; Periodontitis/therapy* ; Guided Tissue Regeneration, Periodontal/methods* ; Regeneration ; Biocompatible Materials ; Tissue Engineering/methods*

Adipose tissue-derived mesenchymal stem cells (ADSCs) are crucially involved in various biological processes because of their self-renewal, multi-differentiation, and immunomodulatory activities. Some ADSC's characteristics have been associated with the basic theory of Chinese medicine (CM), especially the Meridian theory. CM can improve the biological properties of ADSCs to facilitate their use in injury treatment, restore immune homeostasis, and inhibit inflammatory responses. Therefore, the combination of CM and ADSCs may be a new promising research direction in integrative medicine of China. This review summarizes the association between CM and ADSCs to assess the potential application value of their combination against various diseases.
Mesenchymal Stem Cells/cytology* ; Adipose Tissue/cytology* ; Humans ; Medicine, Chinese Traditional ; Integrative Medicine ; Animals

OBJECTIVE: To investigate the effect of miR-483-5p on hepatocellular carcinoma (HCC) cells proliferation and stemness, as well as the attenuating effect of Pien Tze Huang (PZH). METHODS: Differentially expressed miRNA between HepG2 cells and hepatic cancer stem-like cells (HCSCs) were identified by a miRNA microarray assay. miR-483-5p mimics were transfected into HepG2 cells to explore the effects of miR-483-5p on cell proliferation and stemness. HepG2 cells and HCSCs were treated with PZH (0, 0.25, 0.50 and 0.75 mg/mL) to explore the effects of PZH on the proliferation and stemness, both in non-induced state and the state induced by miR-483-5p mimics. RESULTS: miR-483-5p was significantly up-regulated in HCSCs and its overexpression increased cell proliferation and stemness in HepG2 cells (P<0.05). PZH not only significantly inhibited proliferation in HepG2 cells, but also significantly suppressed the cell proliferation and self-renewal of HCSCs (P<0.05). The effects of miR-483-5p mimics on proliferation and stemness of HepG2 cells were partially abolished by PZH. CONCLUSIONS miR-483-5p promotes proliferation and enhances stemness of HepG2 cells, which were attenuated by PZH, demonstrating that miR-483-5p is a potential molecular target for the treatment of HCC and provide experimental evidence to support clinical use of PZH for patients with HCC.
Humans ; MicroRNAs/metabolism* ; Cell Proliferation/drug effects* ; Liver Neoplasms/drug therapy* ; Carcinoma, Hepatocellular/drug therapy* ; Hep G2 Cells ; Neoplastic Stem Cells/metabolism* ; Drugs, Chinese Herbal/therapeutic use* ; Gene Expression Regulation, Neoplastic/drug effects*

OBJECTIVE: To investigate the Wnt signaling pathway and miRNAs mechanism of extracts of Plastrum Testudinis (PT) in the treatment of osteoporosis (OP). METHODS: Thirty female Sprague Dawley rats were randomly divided into 5 groups by random number table method, including sham group, ovariectomized group (OVX), ovariectomized groups treated with high-, medium-, and low-dose PT (160, 80, 40 mg/kg per day, respectively), with 6 rats in each group. Except for the sham group, the other rats underwent bilateral ovariectomy to simulate OP and received PT by oral gavage for 10 consecutive weeks. After treatment, bone mineral density was measured by dual-energy X-ray absorptiometry; bone microstructure was analyzed by micro-computed tomography and hematoxylin and eosin staining; and the expressions of osteogenic differentiation-related factors were detected by immunochemistry, Western blot, and quantitative polymerase chain reaction. In addition, Dickkopf-1 (Dkk-1) was used to inhibit the Wnt signaling pathway in bone marrow mesenchymal stem cells (BMSCs) and miRNA overexpression was used to evaluate the effect of miR-214 on the osteogenic differentiation of BMSCs. Subsequently, PT extract was used to rescue the effects of Dkk-1 and miR-214, and its impacts on the osteogenic differentiation-related factors of BMSCs were evaluated. RESULTS: PT-M and PT-L significantly reduced the weight gain in OVX rats (P<0.05). PT also regulated the bone mass and bone microarchitecture of the femur in OVX rats, and increased the expressions of bone formation-related factors including alkaline phosphatase, bone morphogenetic protein type 2, collagen type I alpha 1, and runt-related transcription factor 2 when compared with the OVX group (P<0.05 or P<0.01). Meanwhile, different doses of PT significantly rescued the inhibition of Wnt signaling pathway-related factors in OVX rats, and increased the mRNA or protein expressions of Wnt3a, β-catenin, glycogen synthase kinase-3β, and low-density lipoprotein receptor-related protein 5 (P<0.05 or P<0.01). PT stimulated the osteogenic differentiation of BMSCs inhibited by Dkk-1 and activated the Wnt signaling pathway. In addition, the expression of miR-214 was decreased in OVX rats (P<0.01), and it was negatively correlated with the osteogenic differentiation of BMSCs (P<0.01). MiR-214 mimic inhibited Wnt signaling pathway in BMSCs (P<0.05 or P<0.01). Conversely, PT effectively counteracted the effect of miR-214 mimic, thereby activating the Wnt signaling pathway and stimulating osteogenic differentiation in BMSCs (P<0.05 or P<0.01). CONCLUSION PT stimulates bone formation in OVX rats through β-catenin-mediated Wnt signaling pathway, which may be related to inhibiting miR-214 in BMSCs.
Animals ; MicroRNAs/genetics* ; Female ; Rats, Sprague-Dawley ; Wnt Signaling Pathway/genetics* ; Osteogenesis/genetics* ; Mesenchymal Stem Cells/cytology* ; Cell Differentiation/drug effects* ; Bone Density/drug effects* ; Ovariectomy ; Osteoporosis/drug therapy* ; beta Catenin/metabolism* ; Rats ; Intercellular Signaling Peptides and Proteins/metabolism* ; Drugs, Chinese Herbal/pharmacology*

OBJECTIVES: The core pathology of osteoporosis lies in bone resorption exceeding bone formation; thus, promoting osteogenesis is a key therapeutic strategy. The osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) forms the biological basis of bone formation. Astragaloside IV (A-IV), a major active component of Astragalus membranaceus, is known to enhance osteogenesis, but its precise molecular mechanisms remain unclear. This study aims to investigate the effects of A-IV on the proliferation and osteogenic differentiation of BMSCs from osteoporotic rats and to elucidate its molecular mechanism through the regulation of microRNA-21 (miR-21) and Notch2 expression. METHODS: After 1 week of adaptive feeding, mature female SD rats were randomly divided into a sham-operated (Sham) group (n=4) and an ovariectomized (OVX) group (n=8) to establish an osteoporosis model. Twelve weeks after surgery, BMSCs were isolated from femoral bone marrow and cultured. Cells were divided into a S-BMSCs group (from Sham), an O-BMSCs group (from OVX), and an A-BMSCs group (from OVX-derived BMSCs treated with A-IV). S-BMSCs and O-BMSCs were induced for osteogenic differentiation using osteogenic induction medium, whereas A-BMSCs were treated with A-IV before induction. Flow cytometry was used to identify mesenchymal stem cell surface markers (CD29) and hematopoietic stem cell marker (CD34) to confirm BMSC characteristics. Cell proliferation was assessed using the methyl thiazolyl tetrazolium (MTT) assay. Alizarin red staining was performed to quantify calcium nodule formation, and alkaline phosphatase (ALP) activity assays were used to evaluate osteogenic differentiation. Real-time reverse transcription PCR (real-time RT-PCR) was used to detect changes in osteogenic-related genes, runt-related transcription factor 2 (Runx2) and osteopontin (OPN), as well as miR-21 expression. Western blotting was performed to assess Runx2, OPN, and Notch2 protein expression. RESULTS: Flow cytometry confirmed that O-BMSCs retained the phenotypic characteristics of mesenchymal stem cells. A-IV significantly enhanced the proliferation of BMSCs from osteoporotic rats (P<0.05), increased ALP activity, and upregulated the mRNA and protein expression of Runx2 and OPN (P<0.05). Bioinformatic and experimental analyses demonstrated that miR-21 directly targeted Notch2. A-IV treatment increased miR-21 expression while suppressing Notch2 protein expression and inhibiting activation of the Notch signaling pathway (P<0.05). CONCLUSIONS Astragaloside IV promotes the osteogenic differentiation of BMSCs derived from osteoporotic rats by upregulating miR-21 expression and inhibiting the key Notch signaling protein Notch2, thereby relieving the Notch2-mediated suppression of osteogenesis.
Animals ; Triterpenes/pharmacology* ; Saponins/pharmacology* ; Osteogenesis/drug effects* ; MicroRNAs/metabolism* ; Rats, Sprague-Dawley ; Female ; Cell Differentiation/drug effects* ; Mesenchymal Stem Cells/drug effects* ; Signal Transduction/drug effects* ; Osteoporosis/pathology* ; Rats ; Cells, Cultured ; Receptor, Notch2/metabolism* ; Receptors, Notch/metabolism* ; Ovariectomy ; Cell Proliferation/drug effects*