Effects of norepinephrine­induced activation of rat vascular adventitial fibroblasts on proliferation and migration of BMSCs involved in vascular remodeling.

Vascular remodeling caused by vascular injury such as hypertension and atherosclerosis is a complex process involving a variety of cells and factors, and the mechanism is unclear. A vascular injury model was simulated by adding norepinephrine (NE) to culture medium of vascular adventitial fibroblasts (AFs). NE induced activation and proliferation of AFs. To investigate the association between the AFs activation and bone marrow mesenchymal stem cells (BMSCs) differentiation in vascular remodeling. BMSCs were cultured with supernatant of the AFs culture medium. BMSC differentiation and migration were observed by immunostaining and Transwell assay, respectively, while cell proliferation was measured using the Cell Counting Kit-8. Expression levels of smooth muscle actin (α-SMA), TGF-ß1 and SMAD3 were measured using western blot assay. The results indicated that compared with those in the control group, in which BMSCs were cultured in normal medium, expression levels of α-SMA, TGF-ß1 and SMAD3 in BMSCs cultured in medium supplemented with supernatant of AFs, increased significantly (all P<0.05). Activated AFs induced the differentiation of BMSCs into vascular smooth muscle-like cells and promoted proliferation and migration. AFs activated by NE may induce BMSCs to participate in vascular remodeling. These findings may help design and develop new approaches and therapeutic strategies for vascular injury to prevent pathological remodeling.

Ligustrazine ameliorates acute kidney injury through downregulation of NOD2­mediated inflammation.

Ligustrazine has been used to alleviate clinical acute kidney injury (AKI); however, the underlying molecular mechanisms are poorly understood. In order to further elucidate the molecular mechanism underlying its occurrence, the role of nucleotide­binding oligomerization domain­containing 2 (NOD2) in AKI was investigated in the present study, and the results indicated that ligustrazine exerts an important protective effect against AKI in vivo by inhibiting the upregulation of NOD2 expression and reducing apoptosis of kidney cells following ischemia/reperfusion injury in rat models. Furthermore, the inhibitory role of ligustrazine on the upregulation of NOD2 and apoptosis of kidney cells induced by CoCl2 and oxygen and glucose deprivation followed by reoxygenation was investigated in in vitro experiments. The effect of ligustrazine on NOD2 downregulation was partially blocked by inhibiting autophagy. To the best of our knowledge, the results of the present study are the first to provide evidence that ligustrazine can inhibit NOD2­mediated inflammation to protect against renal injury, which may be in part attributed to the induction of autophagy. These findings may help design and develop new approaches and therapeutic strategies for AKI to prevent the deterioration of renal function.

The effects of human umbilical cord-derived mesenchymal stem cell transplantation on endometrial receptivity are associated with Th1/Th2 balance change and uNK cell expression of uterine in autoimmune premature ovarian failure mice.

BACKGROUND: To explore the mechanism of human umbilical cord-derived mesenchymal stem cell (hUMSC) transplantation to improve ovarian function and the endometrial receptivity in autoimmune premature ovarian failure (POF) mice. METHODS: The POF model was established in mice treated with zona pellucida 3 polypeptide fragment (zona pellucida 3, ZP3). The hUMSCs were transplanted into the POF mice through tail vein injection. Following the transplantation, the serum hormone levels of follicle stimulating hormone (FSH), estrogen (E2), progesterone (P), γ-interferon (IFN-γ), interleukin-2 (IL-2), and interleukin-4 (IL-4) were evaluated by ELISA analysis. Morphological changes of ovarian and uterus tissues were examined by HE staining and immunohistochemistry. The expression of Th1/Th2 cytokines of T cells in spleen and CD56+CD16- cells (uterine natural killer cells, uNK cells) in uterine was measured by flow cytometry (FCM) and immunohistochemistry. The expression of HOXA10 in uterine endometrium was examined by immunohistochemistry and RT-PCR analysis. The pinopodes of epithelial cells in uterine endometrium were examined by scanning electron microscopy. RESULTS: Following hUMSC transplantation, the serum levels of E2, P, and IL-4 were increased but FSH, IFN-γ, and IL-2 levels were decreased in POF mice. Also, the transplantation of hUMSCs caused an increase in total number of healthy follicles and decrease of atresia follicles. The expression of HOXA10 gene was significantly increased but the CD56+CD16- uNK cells decreased in the endometrium of uterine. The ratio of Th1/Th2 cytokines was also significantly decreased. CONCLUSION: The data suggest that the recovery of ovarian function and endometrial receptivity in POF mice was regulated by the balance of Th1/Th2 cytokines and expression of uNK cells in the endometrium following hUMSC transplantation.

Apocynin inhibited NLRP3/XIAP signalling to alleviate renal fibrotic injury in rat diabetic nephropathy.

AIMS: In this animal study, we tried to test the hypothesis that apocynin could play an anti-inflammation role by inhibiting NLRP3/X-linked inhibitor of apoptosis protein (XIAP) signalling and have an effect on antifibrosis in rats with diabetic nephropathy. MAIN METHODS: Diabetic nephropathy rats were induced by tail-vein injection of streptozotocin at 60 mg/kg body weight in sodium citrate buffer (0.01 M, pH 4.5) with unrestricted access to food/water for 12 weeks, and rats with blood glucose levels above 18.0 mM were considered diabetic; the damage index for glomerular mesangial cells damage index was calculated by morphological examinations; protein and mRNA changes were analysed by western blotting immunohistochemistry and real-time quantitative polymerase chain reaction; interstitial fibrosis was assessed and scored using Masson's staining. KEY FINDINGS: In rats with diabetic nephropathy, apocynin (1) reduced renal injury and improved renal function; (2) downregulated the expression of NLRP3 in renal cortex; (3) downregulated the expression of XIAP in renal cortex; and (4) attenuated renal fibrosis. SIGNIFICANCE: As an inhibitor of reactive oxygen species (ROS), apocynin could downregulate the expression of NLRP3 and XIAP, and alleviate renal fibrosis, which meant not only that ROS was one type of ligands of NLRP3, but also that ROS mechanism and NLRP3 activation might be therapeutic targets in the treatment of diabetic nephropathy in the future.

Dihydroartemisinin alleviates oxidative stress in bleomycin-induced pulmonary fibrosis.

AIMS: Dihydroartemisinin has been shown to inhibit the development of pulmonary fibrosis in rats, but its mechanism has yet to be elucidated. This study aimed to determine the mechanisms of dihydroartemisinin in bleomycin-induced pulmonary fibrosis in a rat model. MAIN METHODS: Morphological changes and collagen deposition were analyzed via hematoxylin-eosin staining and Masson staining and the expression of biotic-factor-related oxidative stress in lung tissues was assayed with standard assay kits. The expressions of α-SMA, E-cadherin, and Nrf2/HO-1 were detected by Western blot and RT-PCR, and the cell morphology and proliferation of cultured type II alveolar epithelial cells (AECs) were assessed via microscopy and immunocytochemical assay. KEY FINDINGS: Dihydroartemisinin treatment significantly decreased the level of oxidative stress and collagen synthesis and inhibited AECs differentiation in bleomycin-induced pulmonary fibrosis compared to the control group (P < 0.001). SIGNIFICANCE: Our results indicated that dihydroartemisinin might decrease oxidative damage to attenuate lung injury and fibrosis.

hPMSC transplantation restoring ovarian function in premature ovarian failure mice is associated with change of Th17/Tc17 and Th17/Treg cell ratios through the PI3K/Akt signal pathway.

BACKGROUND: Human placenta-derived mesenchymal stem cell (hPMSC) transplantation has been demonstrated to be an effective way of recovering ovarian function in mice with autoimmune induced premature ovarian failure (POF). But the exact mechanism remains unclear. The goal of the present study is to investigate the role of immune factors (T-helper 17 (Th17), cytotoxic T (Tc17) and regulatory T (Treg) cells) in the recovery of ovarian function and whether the phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway is involved in the regulation. METHODS: The inhibitor of PI3K/Akt was administered to observe its effect on ovarian function recovery and immune regulation. Serum levels of estradiol (E2), follicle stimulation hormone (FSH), luteinizing hormone (LH) and anti-Müllerian hormone (AMH)) and anti-Zona pellucida antibody (AZPAb) were measured by ELISA to evaluate ovarian function. The morphological changes of ovaries were observed by HE staining. Apoptosis of granular cells (GCs) was determined by detecting the expression of capase-3. Expression of p-Akt protein was detected by immunohistochemistry and western blot assay in ovarian tissues. The MTT assay was performed to assess GC proliferation. GC apoptosis was performed using flow cytometry analysis. Percentages of Th17, Tc17 and Treg cells were detected by flow cytometry. Expression of interleukin (IL)-17 in serum was measured by ELISA. RESULTS: LY294002 administration decreased serum levels of E2 and AMH, while the levels of FSH, LH and AZPAb in serum were increased compared with mice in the hPMSC transplantation group. The ovarian morphology presented as atrophy and fibrosis, with functional follicles exhausted. The expression of p-Akt in ovarian tissue was significantly decreased. Also, LY294002 administration significantly decreased proliferation and increased cell apoptosis in GCs, and for immune factors the ratios of Th17/Tc17 and Th17/Treg cells were significantly increased, as well as the serum levels of IL-17. CONCLUSIONS: Our data suggest that the PI3K/Akt signal pathway is involved in the recovery of ovarian function by changing the ratios of Th17/ Tc17 and Th17/Treg cells in POF mice following hPMSC transplantation.

Effects of hPMSCs on granulosa cell apoptosis and AMH expression and their role in the restoration of ovary function in premature ovarian failure mice.

BACKGROUND: This study was performed to determine the effects of human placenta mesenchymal stem cell (hPMSC) transplantation on granulosa cell apoptosis and anti-Müllerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR) expression in autoimmune drug-induced premature ovarian failure (POF) mice. The aim of this research is to investigate the mechanisms of hPMSCs on ovarian reserve capacity. METHODS: The POF mice model was established by injection of zona pellucida 3 peptide (pZP3). hPMSC transplantation was conducted by intravenous injection into mice following pZP3 treatment. The follicle number was examined by histopathology. The serum levels of FSH, LH, E2, AMH and anti-zona pellucida antibody (AzpAb) were measured by enzyme-linked immunosorbent assay. AMH and FSHR expression in the ovary was analyzed by immunohistochemistry and western blot analysis. Granulosa cell apoptosis of the ovaries was examined by In Situ Cell Death Detection Kit. Granulosa cells were isolated and treated with SiAmh interference and hPMSC supernatant to observe the effects of AMH expression on granulosa cell apoptosis in vitro. RESULTS: The results showed that hPMSC transplantation can significantly recover the estrus cycle in the POF group. Morphological staining showed that the basal follicles and sinus follicles after hPMSC transplantation were higher in POF mice than in those without treatment, and the follicle number was significantly decreased with atresia. The serum levels of FSH, LH and AzpAb in the hPMSC transplantation group were reduced considerably, but the E2 and AMH levels were significantly increased. After hPMSC transplantation, the AMH and FSHR expression in ovarian tissue was significantly higher than in the POF group as determined by immunochemistry and western blot analysis. The FSHR expression was shown in granulosa cells only, and FSHR expression increases with AMH expressed in the ovary; granulosa cell apoptosis was decreased following hPMSC transplantation. The same results were observed from the in-vitro study. CONCLUSIONS: hPMSC transplantation can significantly improve the serum levels of high gonadotropin and low estrogen of POF mice, promote follicular development, inhibit excessive follicular atresia and granulosa cell apoptosis, and improve the ovarian reserve capacity. The mechanism may be achieved by increasing the expression of AMH and FSHR in ovaries.

Restoring Ovarian Function With Human Placenta-Derived Mesenchymal Stem Cells in Autoimmune-Induced Premature Ovarian Failure Mice Mediated by Treg Cells and Associated Cytokines.

Regulatory T (Treg) cells play a key role in the regulation of autoimmunity and transplantation. Human placenta-derived mesenchymal stem cell (hPMSC) transplantation has a potential to restore ovarian dysfunction associated with premature ovarian failure (POF), while the exact function of the Treg cells in the transplantation still needs to be further investigated. In this study, hPMSCs were intravenously injected into POF mice following zona pellucida glycoprotein 3 (pZP3) treatment. Ovarian function was measured by analyzing estrous cycle, folliculogenesis, and hormone secretion, also, with the detection of apoptotic granular cells (GCs) in ovarian tissues. To determine whether immune response is involved in the regulation of ovarian function change, the population of Treg cell populations and expression of associated cytokines, for example, transforming growth factor ß (TGF-ß) and interferon γ (IFN-γ) were measured. After hPMSCs transplantation, the injured ovarian function is significantly improved. Also, the pZP3-treatment-induced apoptotic GCs were significantly decreased as compared with the POF mice. The transplantation of hPMSCs significantly increased the population of Treg cells which was inhibited by pZP3 treatment. The decrease in TGF-ß and increase in IFN-γ in serum caused by pZP3 treatment have been reversed following hPMSCs transplantation. These findings strongly suggest that the recovery of ovarian function in POF mice is mediated via the regulation of Treg cells and production of associated cytokines following hPMSCs transplantation.

RGS3 inhibits TGF-ß1/Smad signalling in adventitial fibroblasts.

Recent evidence suggests that adventitial fibroblasts (AFs) are crucially implicated in atherosclerosis. However, the mechanisms by which AFs are dysfunctional and contribute to atherosclerosis remain unclear. This study aimed to investigate the role of regulator of G-protein signalling 3 (RGS3) in the regulation of AFs using apoE knockout mouse as the model. Pathological changes in aortic arteries of apoE knockout mice fed with hyperlipid diet were examined by Movat staining. The expression of RGS3, α-SMA, TGF-ß1, Smad2, and Smad3 in the adventitia was detected by immunohistochemistry. Adventitial fibroblasts were isolated from aortic arteries of apoE knockout mice and infected with RGS3 overexpression lentivirus or empty lentivirus. The expression of RGS3, α-SMA, TGF-ß1, Smad2, and Smad3 in AFs was detected by real-time polymerase chain reaction and Western blot analysis. We found that hyperlipidic diet caused significant aortic intima thickening and atherosclerotic plaques in 15-week-old apoE knockout mice. Compared to wild-type mice, RGS3 expression was lower while α-SMA, TGF-ß1, Smad2, and Smad3 expression was higher in the adventitia of apoE knockout mice. In addition, lentivirus mediated overexpression of RGS3 caused decreased expression of α-SMA, TGF-ß1, Smad2, and Smad3 in AFs derived from apoE(-/-) mice. In conclusion, these results suggest that RGS3 may provide protection against pathological changes of AFs and the development of atherosclerosis by inhibiting TGF-ß1/Smad signalling. RGS3 may be a potential therapeutic target for atherosclerosis.

Role of SDF-1/CXCR4 and cytokines in the development of ovary injury in chemotherapy drug induced premature ovarian failure mice.

OBJECTIVE: To explore the mechanism of chemotherapy drug induced ovarian injury in premature ovarian failure (POF) mice. METHODS: C57BL/6 mice were treated with Cyclophosphamide and Busulfan by intraperitoneal injection. One week after treatment, the estrous cycles, folliculogenesis, ovarian endocrine function and ovarian histopathological changes were evaluated the ovarian function. The serum levels of cytokines, follicle stimulating hormone (FSH) and estradiol (E2) were measured by enzyme-linked immunosorbent assay (ELISA). The protein levels of SDF-1/CXCR4 and FSHR in ovary were evaluated by immunohistochemistry and Western blot analysis. The ovarian cells apoptosis was measured by TUNEL Assay. RESULTS: The ovaries from POF mice show the evidence of reduced ovarian function such as irregular estrous cycles, stromal hyperplasia, decreased follicle numbers, atresia follicles and less granular cell layer as well as corpora luteum. The lower levels of E2 and higher levels of FSH in serum characterize the ovarian injury; a great number of granular apoptotic cells were observed in the POF mice; the serum concentrations of pro-inflammatory cytokines of IL-6, IL-8 and TNF-α level were increased but anti-inflammatory cytokine of IL-10 was decreased. SDF-1/CXCR4 and FSHR expressed in ovaries were detected in the cytoplasm of preantral and antral follicles; the expression of SDF-1/CXCR4 was increased and FSHR was decreased in POF mice. CONCLUSION: Our data suggest that the inflammatory regulation, SDF-1/CXCR4 and cellular apoptosis in ovarian tissues are involved in the development of ovarian injury of POF. These data provide useful information to develop new therapeutic approach to treat POF disorders in the future.

SB-431542, a specific inhibitor of the TGF-ß type I receptor inhibits hypoxia-induced proliferation of pulmonary artery adventitial fibroblasts.

The vascular remodeling process plays an important role in the pathology of hypoxia-induced pulmonary hypertension, and it includes cell proliferation, cell motility, cell synthesis and collagen coagulation. Due to their proliferation and synthesis ability, the adventitial fibroblasts are thought to be critical in the vascular remodeling process initiated in response to hypoxia. However, the factors driving hypoxia-induced fibroblast proliferation and synthesis have yet to be elucidated, and the treatment regimens to treat hypoxia remain ineffective. As forthis study, its purpose was to examine the effects exerted by SB-431542, a small-molecule antagonist of transforming growth factor-ß-receptor, on the proliferation, synthesis and collagen coagulation in cultured adventitial fibroblasts. Another aim of this study was to assess the inhibitory ability of SB-431542 on pulmonary vascular remodeling in chronic hypoxia in vivo.The cell morphology and proliferation of cultured adventitial fibroblasts was assessed by laser confocal microscopy and the MTT assay, respectively. Additionally, collagen synthesis was determined by hydroxyproline chromatography, while the expression of cytokines in adventitial fibroblasts and lung tissues was evaluated by immunohistochemical and reverse transcription PCR analyses. The results indicated that the exposure of cultured fibroblasts to 1% oxygen led to the up regulation of cell proliferation, cell synthesis. In addition, increased expression of cytokines and collagen was detected in vivo in the pulmonary artery adventitia of rats exposed to chronic hypoxia. Conversely, SB-431542 inhibited fibroblast proliferation and synthesis in the process of hypoxia-induced pulmonary hypertension (P < 0.01). Thus, the results suggested that by reducing cell proliferation, cell synthesis of vascular adventitia, small molecule inhibitors of the TGF-ß1 receptors may offer a novel therapy for pulmonary hypertension.

Tissue microRNA-126 expression level predicts outcome in human osteosarcoma.

BACKGROUND: MicroRNA-126 has been found to be consistently under-expressed in osteosarcoma tissues and cell lines compared with normal bone tissues and normal osteoblast cells, respectively. The purpose of the present study was to detect the expression levels of miR-126 in osteosarcoma patients and to further investigate the clinicopathological, and prognostic value of miR-126. METHODS: We recruited 122 patients with osteosarcomas from the Department of Orthopedic Surgery, Yantaishan Hospital between May 2008 and April 2013. The expression level of miR-126 was determined by qRT-PCR. Associations between miR-126 expression and various clinicopathological characteristics were analyzed using the χ (2) test. Survival rate was determined with Kaplan-Meier and statistically analyzed with the log-rank method between groups. Survival data were evaluated through multivariate Cox regression analysis. RESULTS: miR-126 expression was significantly decreased in osteosarcoma tissues compared to adjacent normal bone tissues (2.421 ± 1.250 vs. 6.212 ± 1.843, P = 0.001). We found that low miR-126 expression had significant association with advanced TNM stage (P <0.001), distant metastasis (P <0.001), and higher tumor grade (P = 0.001). Kaplan-Meier survival analysis showed that the miR-126 low-expression group had significantly shorter overall survival time than those with high-expression (log-rank test, P = 0.008). Furthermore, multivariate Cox proportional hazards model analysis showed that miR-126 expression was independently associated with overall survival of patients with osteosarcoma (HR = 3.102, 95 % CI: 1.113-9.023, P = 0.018). CONCLUSIONS: This is the first study revealing that miR-126 down-expression may be related to the prediction of poor prognosis for osteosarcoma patients, suggesting that miR-126 may serve as a prognostic marker for the optimization of clinical treatments.

Dihydroartemisinin supresses inflammation and fibrosis in bleomycine-induced pulmonary fibrosis in rats.

Pulmonary fibrosis is a respiratory disease with a high mortality rate and its pathogenesis involves multiple mechanisms including epithelial cell injury, fibroblast proliferation, inflammation, and collagen coagulation. The treatment regimens still fail to recover this disease. We have previously found that dihydroartemisinin inhibits the development of pulmonary fibrosis in rats. This study aimed to determine the mechanisms of dihydroartemisinin in bleomycin-induced pulmonary fibrosis. The experimental rats were divided into six groups as normal saline control group (NS group), bleomycin group (BLM group), dihydroartemisinin-1, -2, or -3 group (DHA-1, DHA-2 and DHA-3 group) and dexamethasone group (DXM group). In BLM group, rats were treated with intratracheal instillation of bleomycin. NS group received the same volume of saline instead of bleomycin. In DHA-1, DHA-2 and DHA-3 group, in addition to intratracheal instillation of bleomycin, respectively, dihydroartemisinin (25 mg/kg, 50 mg/kg, 100 mg/kg daily) was administrated by intraperitoneal instillation. In DXM group, rats were treated with intraperitoneal instillation of dexamethasone as control. Immunocytochemical assay, reverse transcription PCR and western blot were used for detecting the expression of TGF-ß1, TNF-α, α-SMA and NF-κB in lung tissues. What's more, morphological change and collagen deposition were analyzed by hematoxylin-eosin staining and Masson staining. Collagen synthesis was detected by hydroxyproline chromatometry. Results showed that dihydroartemisinin significantly decreased the amount of inflammatory cytokines and collagen synthesis, and inhibited fibroblast proliferation in bleomycin-induced pulmonary fibrosis (P < 0.001). This study provides experimental evidence that dihydroartemisinin could decrease cytokines, alveolar inflammation and attenuates lung injury and fibrosis.

Effects of hydroxysafflor yellow A on proliferation and collagen synthesis of rat vascular adventitial fibroblasts induced by angiotensin II.

THE PURPOSE OF THIS STUDY WAS TO: 1) examine the effects of hydroxysafflor yellow A (HSYA) on the proliferation, collagen and cytokine synthesis of vascular adventitial fibroblasts as induced by angiotensin II (Ang II) in normal Sprague-Dawley (SD) rats in vitro, and 2) to assess the effects of HSYA on morphological changes and collagen accumulation of vascular adventitia in spontaneously hypertensive rats (SHR) in vivo. In vitro experiment, vascular adventitial fibroblasts from SD rats were isolated, cultured, and divided into control groups, model groups and HSYA groups. Cell morphology of adventitial fibroblasts was assessed using laser confocal microscopy, while cell proliferation with the MTT assay, and collagen synthesis was determined using hydroxyproline chromatometry. Immunocytochemistry and reverse transcription PCR were used for detecting the expression of TGF-ß1, MMP-1, α-SMA and NF-κB in adventitial fibroblasts. In vivo experiment, vascular adventitia proliferation and collagen synthesis were analyzed using hematoxylin-eosin and Sirius staining. Our results showed that: 1) in vitro experiment of SD rats, HSYA inhibited proliferative activity and collagen synthesis of adventitial fibroblasts as induced by Ang II, and the inhibitory effects of HSYA on the increased expression of MMP-1, TGF-ß1, α-SMA and NF-κB p65 as induced by Ang II were assessed, and 2) in vivo experiment of SHR, histological analysis displayed fewer pathological changes of vascular adventitia in HSYA treatment groups as compared with no HSYA treatment groups, and MMP-1, TGF-ß1, α-SMA and NF-κB p65 expression significantly reduced after HSYA treatment (P < 0.05). Our results revealed that HSYA treatment significantly decreased the amount of cytokines and collagen synthesis in vascular adventitia components. This study provides experimental evidence demonstrating that HSYA has the capacity to decrease vascular adventitia proliferation and hyperplasia during vascular remodeling.

Effects of BMSCs interactions with adventitial fibroblasts in transdifferentiation and ultrastructure processes.

In this study an in vitro model of simulated blood vessel injury was used to study the effects of bone marrow-derived mesenchymal stem cells (BMSCs) morphology and to detect vascular smooth muscle actin (SM α-actin) expression in the presence of adventitial fibroblasts. BMSCs from rats with DAPI-labeled nuclei were co-cultured with adventitial fibroblasts for 7 days, while BMSCs cultured alone served as controls. Cell morphology of BMSCs was assessed by laser confocal microscopy and SM α-actin or calponin expression in BMSCs was detected by immunofluorescence staining. The expression of SM α-actin mRNA was identified using RT-PCR. Cell ultrastructure was assessed by electron microscopy. The results demonstrate that BMSCs with DAPI-labeled nuclei were smaller compared with fibroblasts, and their nuclei emitted a blue fluorescence. Most BMSCs displayed a polygonal shape changing from their original long fusiform shape. BMSCs with blue nuclei and red cytoplasm (SM α-actin positive or calponin positive) were observed, and a substantial number of filaments were present in the cytoplasm as observed under electron microscopy. The number of these cells increased as a function of culture duration. However, SM α-actin expression was weak and calponin expression was not detected in the control group. This study provides important new information on the characterization of artherosclerosis pathogenesis and vascular restenosis after blood vessel injury. Our findings demonstrate that direct interactions with adventitial fibroblasts can induce vascular smooth muscle-like cell differentiation in BMSCs.