首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Emodin induces embryonic toxicity in mouse blastocysts through apoptosis   总被引:1,自引:0,他引:1  
Chang MH  Huang FJ  Chan WH 《Toxicology》2012,299(1):25-32
Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a major constituent of rhubarb, has a wide range of therapeutic applications. Previous studies have established that emodin inhibits cell proliferation and induces caspase 3-dependent apoptosis. However, its side-effects, particularly those on embryonic development, have not been well characterized as yet. In the current study, we examined the cytotoxic effects of emodin on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, and in vivo implantation by embryo transfer. Blastocysts treated with 25-75 μM emodin exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rate of blastocysts pretreated with emodin was lower than that of their control counterparts. Moreover, in vitro treatment with 25-75 μM emodin was associated with increased resorption of post-implantation embryos and decreased fetal weight. With the aid of an in vivo mouse model, we showed that consumption of drinking water containing emodin led to apoptosis and decreased cell proliferation, and inhibited early embryonic development to the blastocyst stage. Our findings support a degree of selective inhibition of retinoic acid receptors in blastocysts treated with emodin. In addition, emodin appears to induce injury in mouse blastocysts through intrinsic apoptotic signaling processes to impair sequent embryonic development. These results collectively indicate that emodin has the potential to induce embryonic cytotoxicity.  相似文献   

2.
Silver nanoparticles (nanoAg) are antibacterial materials widely used in various products and medical supplies. In this report, we examined the cytotoxic effects of nanoAg on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, and in vivo implantation by embryo transfer. Blastocysts treated with 50 μM nanoAg exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Importantly, the implantation success rate of blastocysts pretreated with nanoAg was lower than that of their control counterparts. Moreover, in vitro treatment with 50 μM nanoAg was associated with increased resorption of post-implantation embryos and decreased fetal weight. Our results collectively indicate that in vitro exposure to nanoAg induces apoptosis and retards early post-implantation development after transfer to host mice. However, nanoAg-stimulated embryonic cytotoxicity appeared lower than that induced by the Ag+ ion. The results collectively show that nanoAg has the potential to induce embryo cytotoxicity. Further studies are required to establish effective protection strategies against the cytotoxic effects of these nanoparticles.  相似文献   

3.
Previously, we reported that sanguinarine, a phytoalexin with antimicrobial, anti‐oxidant, anti‐inflammatory and pro‐apoptotic effects, is a risk factor for normal embryonic development that triggers apoptotic processes in the inner cell mass of mouse blastocysts, causing decreased embryonic development and cell viability. In the current study, we investigated the deleterious effects of sanguinarine on mouse oocyte maturation, in vitro fertilization (IVF), and subsequent pre‐ and postimplantation development both in vitro and in vivo. Notably, sanguinarine significantly impaired mouse oocyte maturation, decreased IVF rates, and inhibited subsequent embryonic development in vitro. Preincubation of oocytes with sanguinarine during in vitro maturation induced an increase in postimplantation embryo resorption and a decrease in mouse fetal weight. In an in vivo animal model, 1 to 5 μM sanguinarine, provided in drinking water, caused a decrease in oocyte maturation and IVF, and led to deleterious effects on early embryonic development. Importantly, preincubation of oocytes with a caspase‐3‐specific inhibitor effectively blocked sanguinarine‐triggered deleterious effects, clearly implying that embryonic injury induced by sanguinarine is mediated by a caspase‐dependent apoptotic mechanism. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 946–955, 2015.  相似文献   

4.
Sanguinarine is an alkaloid with known antibiotic and anti-inflammatory activity and its pharmacokinetics have been studied in the rat after a single oral dose (10?mg?kg?1 body weight). Alkaloid determination in the plasma and liver was carried out by high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC/ESI-MS). The pharmacokinetic parameters (tmax, cmax, AUC0→t and AUC0→∞) were determined for sanguinarine and dihydrosanguinarine, the major components detected in plasma. The first step in sanguinarine metabolism in the rat was the reduction of the iminium bond resulting in formation of the less toxic dihydrosanguinarine. Both compounds were completely eliminated from the plasma and liver after 24?h and not detected in urine. After a single oral dose of 3H-sanguinarine, more than 42% of the ingested radioactivity was present in gastrointestinal tract. Benz[c]acridine, up to date the only sanguinarine metabolite referred to in the literature, was not detected in the plasma, liver or urine.  相似文献   

5.
The mycotoxin citrinin (CTN), a natural contaminant in foodstuffs and animal feeds, exerts cytotoxic and genotoxic effects on various mammalian cells. An earlier study by our group shows that CTN has cytotoxic effects on mouse embryonic stem cells and blastocysts, and is associated with defects in their subsequent development, both in vitro and in vivo. Here, we further investigate the effects of CTN on oocyte maturation, and subsequent pre- and postimplantation development in vitro and in vivo. CTN induced a significant reduction in the rate of oocyte maturation, fertilization, and in vitro embryo development. Treatment of oocytes with 5 microM CTN during in vitro maturation (IVM) led to increased resorption of postimplantation embryos, and decreased placental and fetal weight. Using an in vivo mouse model, we show that consumption of drinking water containing 5 microM CTN results in decreased oocyte maturation and in vitro fertilization, as well as early embryonic developmental injury. To our knowledge, this is the first study investigating the impact of CTN on maturation of mouse oocytes, fertilization, and sequential embryonic development.  相似文献   

6.
Ochratoxin A (OTA), a mycotoxin constituent of a range of food commodities, including coffee, wine, beer, grains, and spices, exerts toxicological and pathological effects in vivo, such as nephrotoxicity, hepatotoxicity, and immunotoxicity. In a previous report, we highlighted the potential of OTA to induce apoptosis via reactive oxygen species (ROS) generation in mouse blastocysts that led to impaired preimplantation and postimplantation embryo development in vitro and in vivo. Here, we have shown that liquiritigenin (LQ), a type of flavonoid isolated from Glycyrrhiza radix, effectively protects against OTA‐mediated apoptosis and inhibition of cell proliferation in mouse blastocysts. Preincubation of blastocysts with LQ clearly prevented OTA‐triggered impairment of preimplantation and postimplantation embryonic development and fetal weight loss, both in vitro and in vivo. Detailed investigation of regulatory mechanisms revealed that OTA mediated apoptosis and embryotoxicity through ROS generation, loss of mitochondrial membrane potential (MMP), and activation of caspase‐9 and caspase‐3, which were effectively prevented by LQ. The embryotoxic effects of OTA were further validated in an animal model in vivo. Intravenous injection of dams with OTA (3 mg/kg/day) led to apoptosis of blastocysts, impairment of embryonic development from zygote to blastocyst stage and decrease in day 18 fetal weight. Notably, preinjection of dams with LQ (5 mg/kg/day) effectively prevented OTA‐induced apoptosis and toxic effects on embryo development. Our collective results clearly demonstrate that OTA exposure via injection has the potential to damage preimplantation and postimplantation embryonic development against which LQ has a protective effect.  相似文献   

7.
This study was aimed at evaluating the potential application of benzophenanthridine alkaloids, sanguinarine and cheleritrine, in the therapy of melanoma cancer. In vitro antiproliferative activity of sanguinarine was higher than that of cheleritrine against the B16 melanoma 4A5 cells. Both agents were able to produce DNA breaks, and the DNA unwinding assay showed that they act as DNA intercalating agents. Sanguinarine was selected for determination of its in vivo preclinical efficacy. Oral treatment with sanguinarine reduced the tumor burden in a transplantable murine tumor grown in a syngeneic host (B16 melanoma 4A5 in C57BL/6 mice), and in a human tumor xenograft grown in immunodeficient mice (A375 human melanoma in athymic nude mice). In A375 tumors a significant decrease in the proliferation marker Ki67, and a reduction in the activated mitogen-activated protein kinases (p-p44/42 MAPK), and in protein kinase B (pAKT) were also observed. Three out of eleven A375-bearing treated mice were tumor-free at the end of treatment, and did not develop any tumor after a further, treatment-free, observation period of 60 days. Sanguinarine also showed a striking antiangiogenic activity in mice. Data from the present study support the concept that sanguinarine can be effective in melanoma skin cancer.  相似文献   

8.
Silver nanoparticles (AgNPs) are antibacterial materials widely used in numerous products and medical supplies. Previously, we showed that AgNPs trigger apoptotic processes in mouse blastocysts, leading to a decrease in cell viability and impairment of preimplantation and postimplantation embryonic development in vitro and in vivo. In the present study, we further investigated the hazardous effects of AgNPs on mouse oocyte maturation, in vitro fertilization (IVF), and subsequent preimplantation and postimplantation development in vitro and in vivo. Data from in vitro experiments revealed that AgNPs impair mouse oocyte maturation, decrease IVF rates, and induce injury effects on subsequent embryonic development to a significant extent. In an animal model, intravenous injection of AgNPs (5 mg/kg body weight) led to a significant decrease in mouse oocyte maturation and IVF concomitant with impairment of early embryonic development in vivo. Importantly, pretreatment with N‐acetylcysteine effectively prevented AgNP‐triggered reactive oxygen species (ROS) production and apoptosis, clearly suggesting a critical role of ROS as an upstream initiator or key regulator of AgNP‐induced hazardous effects on oocyte maturation and sequent embryonic development. Furthermore, preincubation of oocytes with Ac‐DEVD‐cho, a caspase‐3‐specific inhibitor, effectively prevented hazardous effects, highlighting the potential involvement of caspase‐dependent apoptotic signaling cascades in AgNP‐mediated events. Expression levels of p53 and p21 of blastocysts were upregulated upon preincubation of mouse oocytes with AgNPs. Our collective results imply that cell apoptosis in mouse blastocysts derived from the AgNP‐pretreated oocytes via intracellular ROS generation, which is further mediated through p53‐, p21‐, and caspase‐3‐dependent regulatory mechanisms.  相似文献   

9.
Embryotoxic factors existing in maternal sera may influence their effects via specific binding to, or alteration of cell surface molecules in the conceptus. This study was undertaken to determine the effects of sera from women with unexplained recurrent spontaneous abortion (URSA) on cell surface glycoconjugates of the early conceptus. Four cell stage embryos were cultured in medium supplemented with sera from women with URSA, from normal women, or in medium without serum. Developmental competence was assessed as the stage distribution of embryos advancing to during 96 h in culture. Hatched (expanded) blastocysts were stained with wheat germ agglutinin (WGA), peanut agglutinin (PNA) and dolichos biflorus agglutinin (DBA) to detect surface glucoconjugates. We observed that patient sera could be divided into high- and low-risk groups on the basis of the ability to decrease the number of four-cell embryos reaching the expanded blastocyst stage. Furthermore, the intensity of reactivity to PNA changed after exposure to high-risk sera. Morula formation was reduced and blastocyst formation was delayed. Although the sera from women with URSA had embryotoxic effects, no influence on the glycoconjugate patterns were evident in hatched blastocysts, aside from PNA reactivivity. We suggest altered developmental display of PNA-reactive proteins was a biomarker for poor developmental quality due to emrbyotoxic factors in serum from URSA patients.  相似文献   

10.
Expanded mouse blastocysts incubated with 1 to 2 microM methylmercury (MeHg) in modified Eagle's basal medium (BME + AA), which contains amino acids, collapsed and degenerated within 24 h. In contrast, blastocysts incubated with the same concentration of MeHg in egg culture medium (ECM), which does not contain amino acids, survived and remained expanded as control embryos did. By systematically omitting each BME amino acid from BME + AA and adding each BME amino acid to egg culture medium, we determined that L-cystine (0.5 mM in BME + AA) was the component of BME + AA that was responsible for the enhancement of the toxicity of MeHg. The shortest incubation time during which the cystine-enhanced MeHg toxicity became irreversible was 2 h, and the addition of any of the neutral BME amino acids (except threonine) or non-BME neutral amino acids (alanine, glycine, or serine) during the 2 h incubation eliminated or reduced the cystine-enhanced MeHg toxicity. Basic amino acids (except histidine) were less effective in protecting embryos: Glutamine and lysine reduced the toxic effect only slightly, and arginine had no effect. DL-buthionine sulfoximine (7.5 mM), a specific inhibitor of glutathione, also reduced cystine-enhanced MeHg toxicity. It therefore appears that cystine enhances MeHg toxicity indirectly, at least in part, by stimulating the synthesis of cellular glutathione, which may in turn enhance MeHg transport. In the absence of cystine, 10 microM MeHg (2 h incubation) was necessary to cause the collapse and degeneration of all blastocysts treated.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
Sanguinarine is a natural compound isolated from the roots of Macleaya cordata and M. microcarpa, has been reported to possess several biological activities such as anti-inflammatory and anti-oxidant effects. In the present study, we demonstrated that sanguinarine markedly induces the expression of HO-1 which leads to a neuroprotective response in mouse hippocampus-derived neuronal HT22 cells from apoptotic cell death induced by glutamate. Sanguinarine significantly attenuated the loss of mitochondrial function and membrane integrity associated with glutamate-induced neurotoxicity. Sanguinarine protected against glutamate-induced neurotoxicity through inhibition of HT22 cell apoptosis. JC-1 staining, which is a well-established measure of mitochondrial damage, was decreased after treatment with sanguinarine in glutamate-challenged HT22cells. In addition, sanguinarine diminished the intracellular accumulation of ROS and Ca2+. Sanguinarine also induced HO-1, NQO-1 expression via activation of Nrf2. Additionally, we found that si RNA mediated knock-down of Nrf2 or HO-1 significantly inhibited sanguinarine-induced neuroprotective response. These findings revealed the therapeutic potential of sanguinarine in preventing the neurodegenerative diseases.  相似文献   

12.
Sanguinarine is a benzopheanthridine alkaloid present in the root of Sanguinaria canadensis L. and Chellidonium majus L. In this study, sanguinarine (2 and 3 microM) exhibited cytotoxicity to KB cancer cells by decreasing MTT reduction to 83% and 52% of control after 24-h of exposure. Sanguinarine also inhibited the colony forming capacity (>52-58%) and growth of KB cancer cells at concentrations higher than 0.5-1 microM. Short-term exposure to sanguinarine (>0.5 microM) effectively suppressed the adhesion of KB cells to collagen and fibronectin (FN). Sanguinarine (2 and 3 microM) induced evident apoptosis as indicated by an increase in sub-G0/G1 populations, which was detected after 6-h of exposure. Only a slight increase in cells arresting in S-phase and G2/M was noted. Induction of KB cell apoptosis and necrosis by sanguinarine (2 and 3 microM) was further confirmed by Annexin V-PI dual staining flow cytometry and the presence of DNA fragmentation. The cytotoxicity by sanguinarine was accompanied by an increase in production of reactive oxygen species (ROS) and depolarization of mitochondrial membrane potential as indicated by single cell flow cytometric analysis of DCF and rhodamine fluorescence. NAC (1 and 3 mM) and catalase (2000 U/ml) prevented the sanguinarine-induced ROS production and cytotoxicity, whereas dimethylthiourea (DMT) showed no marked preventive effect. These results suggest that sanguinarine has anticarcinogenic properties with induction of ROS production and mitochondrial membrane depolarization, which mediate cancer cell death.  相似文献   

13.
We examined the effects of sanguinarine, a benzophenanthridine alkaloid, on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death in a human colorectal cancer HCT-116 cell line. Sanguinarine generated ROS, which was followed by a decrease in the mitochondrial membrane potential (MMP), the activation of caspase-9 and -3, and the down-regulation of anti-apoptotic proteins, such as Bcl2, XIAP and cIAP-1. Sanguinarine also promoted the activation of caspase-8 and truncation of Bid (tBid). However, the quenching of ROS generation by N-acetyl-l-cysteine, a scavenger of ROS, reversed the sanguinarine-induced apoptosis effects via inhibition of the MMP collapse, tBid expression, and activation of caspases. Sanguinarine also markedly induced the expression of the early growth response gene-1 (Egr-1) during the early period, after which expression level was decreased. In addition, HCT-116 cells transfected with Egr-1 siRNA displayed significant blockage of sanguinarine-induced apoptotic activity in a ROS-dependent manner. These observations clearly indicate that ROS, which are key mediators of Egr-1 activation and MMP collapse, are involved in the early molecular events in the sanguinarine-induced apoptotic pathway acting in HCT-116 cells.  相似文献   

14.
Previous studies have shown that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can arrest molar tooth development in rats after in utero and lactational exposure, and that the sensitive stage is temporally restricted. To define the stage in which TCDD is able to arrest tooth development and the cellular background of the effect, mouse embryonic molar tooth explants including various early developmental stages from initiation to late cap stage were exposed to TCDD in organ culture. TCDD did not inhibit morphogenesis of the first molar teeth including the early bud-staged E12 first molars, but the teeth were smaller than in control cultures. Accordingly, the second molars underwent morphogenesis in the presence of TCDD when explanted at E15 when they were at the bud stage. TCDD arrested their development when explanted at E14 when they had not yet reached the early bud stage. Immunohistochemical localization of incorporated bromodeoxyuridine in cultured E14 teeth showed that TCDD did not affect cell proliferation. Localization of apoptosis by terminal deoxynucleotidyl transferase (TdT)-mediated nick end labeling (TUNEL) method revealed that TCDD enhanced apoptosis of dental epithelial cells, especially in the dental lamina of both the first and second molars, and in the inner dental epithelium at the cusp tips of the first molars. Thus, TCDD can arrest tooth development in vitro if the exposure starts at the initiation stage, whereas exposure at later stages leads to smaller tooth size and deformation of cuspal morphology. TCDD interferes with tooth development by stimulating apoptosis in those cells of the dental epithelium, which are predetermined to undergo apoptosis during normal development.  相似文献   

15.
张军强  武恂  曹善仁  周林  赵纯  凌秀凤 《江苏医药》2013,39(10):1147-1149
目的比较两种囊腔人工皱缩(AS)预处理方法在人囊胚玻璃化冻融中的应用效果。方法囊胚玻璃化冷冻复苏患者564例分为两组:A组201例,采用注射针抽穿AS法;B组363例,采用激光打孔AS法。比较两组的相关结果。结果 A组平均移植囊胚数(1.72±0.67)个,B组平均移植囊胚数(1.72±0.52)个;A、B组冷冻囊胚复苏后的存活率和孵出率分别为92.1%和79.0%、94.6%和79.6%,A组和B组玻璃化冻融移植后临床妊娠率、种植率、活产率、流产率分别为51.8%、38.4%、42.4%、18.2%和56.4%、43.2%、46.7%、16.3%,两组在以上各指标间均无统计学差异(P>0.05)。结论两种囊腔AS法均是有效的预处理方法,激光打孔AS法效果可能稍好一些。  相似文献   

16.
Apoptosis may occur in early embryos where the execution of essential developmental events has failed, and gangliosides, sialic acid-conjugated glycosphingolipids, are proposed to regulate cell differentiation and growth. To evaluate the regulatory roles of ganglioside GM3 in early embryonic development, this study examined its expressional patterns in apoptotic cells during early embryonic development in mice. Pre-implanted embryos were obtained by in vitro fertilization, which were treated at the 4-cell stage with three the apoptosis inducers, actinomycin D, camptothecin and cycloheximide, for 15 h. All three inducers significantly increased the percentage of apoptotic cells, as measured using a TUNEL method, but remarkably reduced the total cell numbers. The numbers of morula and blastocyst stages were significantly decreased by treatment of the embryos with the three apoptosis inducers compared with the control, with a similar result also observed in the number of blastomeres. Staining of early embryos with Hoechst 33342 revealed a significant percentage of apoptotic nuclei. Prominent immunofluorescence microscopy revealed a significant difference in the ganglioside GM3 expression in apoptotic embryos compared with the control, and RT-PCR also demonstrated a dramatic increase in ganglioside GM3 synthase mRNA in the apoptotic embryos. These results suggest that ganglioside GM3 may be pathophysiologically implicated in the regulation of early embryonic development through an apoptotic mechanism.  相似文献   

17.
《Environmental toxicology》2018,33(3):280-294
Berberine, an isoquinoline alkaloid isolated from several traditional Chinese herbal medicines, has been shown to suppress growth and induce apoptosis in some tumor cell lines. However, berberine has also been reported to attenuate H2O2‐induced oxidative injury and apoptosis. The basis for these ambiguous effects of berberine—triggering or preventing apoptosis—has not been well characterized to date. In the current investigation, we examined whether berberine exerts cytotoxic effects on mouse embryos at the blastocyst stage and affects subsequent embryonic development in vitro and in vivo. Treatment of blastocysts with berberine (2.5‐10 μM) induced a significant increase in apoptosis and a corresponding decrease in trophectoderm cell number. Moreover, the implantation success rate of blastocysts pretreated with berberine was lower than that of their control counterparts. Pretreatment with berberine was also associated with increased resorption of postimplantation embryos and decreased fetal weight. In an animal model, intravenous injection of berberine (2, 4, or 6 mg/kg body weight/d) for 4 days resulted in apoptosis of blastocyst cells and early embryonic developmental injury. Berberine‐induced injury of mouse blastocysts appeared to be attributable to oxidative stress‐triggered intrinsic apoptotic signaling processes that impaired preimplantation and postimplantation embryonic development. Taken together, our results clearly demonstrate that berberine induces apoptosis and retards early preimplantation and postimplantation development of mouse embryos, both in vitro and in vivo.  相似文献   

18.
采用一种灵敏,准确,简便的致突变研究方法,收集ig阿司匹林(Asp)对乙酰氨基酚(Par)及布洛芬(Ibu)的妊娠d 4大鼠胚泡进行微核试验,结果表明,孕后d3给Asp为微核产生高峰期;Asp>0.5g·kg~(-1),Par>0.25g·kg~(-1)时呈显著的胚泡微核诱导作用,而Ibu0.5g·kg~(-1)则无此效应,Asp各组微核呈依剂量增加,三药对同体孕鼠骨髓均无显著微核诱导作用,结果提示Asp和Par具遗传毒性,并证实整体大鼠着床前胚泡对某些化学物质的染色体断裂作用较骨髓细胞更为敏感。  相似文献   

19.
Introduction: The advent of stem cell technology has seen the establishment of embryonic stem cells (ESCs) as molecular model systems and screening tools. Although ESCs are nowadays widely used in research, regulatory implementation for developmental toxicity testing is pending.

Areas Covered: This review evaluates the performance of current ESC, including human (h)ESC testing systems, trying to elucidate their potential for developmental toxicity testing. It shall discuss defining parameters and mechanisms, their relevance and contemplate what can realistically be expected. Crucially this includes the question of how to ascertain the quality of currently employed cell lines and tests based thereon. Finally, the use of hESCs will raise ethical concerns which should be addressed early on.

Expert Opinion: While the suitability of (h)ESCs as tools for research and development goes undisputed, any routine use for developmental toxicity testing currently still seems premature. The reasons for this comprise inherent biological deficiencies as well as cell line quality and system validation. Overcoming these issues will require collaboration of scientists, test developers and regulators. Also, validation needs to be made worthwhile for academia. Finally we have to continuously rethink existing strategies, making room for improved testing and innovative approaches.  相似文献   


20.
绒毛染色体核型和病原体检测与胚停育的关系   总被引:6,自引:0,他引:6  
目的探讨绒毛染色体核型和宫颈分泌物病原体检测在胚停育中的作用。方法对49例胚停育组,30例对照组(正常早孕要求行人工流产的妇女)采用①胚胎绒毛组织行染色体检查;②取宫颈分泌物,用培养法行解脲支原体(UU)检测;用免疫层析法,行沙眼衣原体(CT)检测。结果胚停育组染色体异常占61%(30/49),对照组占19%(6/31),胚停育组明显高于对照组,差异有统计学意义(P<0.01)。支原体感染同时伴染色体异常占24%(12/49),对照组占3%(1/31),胚停育组明显高于对照组,差异有统计学意义(P<0.01)。支原体感染胚停育组与对照组相比,差异无统计学意义(P>0.05)。原体感染胚停育组与对照组相比,差异无统计学意义(P>0.05)。结论染色体异常在胚停育中起重要作用,染色体异常时支原体感染也起一定作用。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号