The effects of oral glutamine on cisplatin-induced genotoxicity in Wistar rat bone marrow cells

Several studies have suggested that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that result from treatment with antineoplastic agents. The emphasis of the present study was to investigate whether the administration of a single dose of oral glutamine had any protective effect against cisplatin-induced clastogenicity. Cisplatin was administered to Wistar rats either alone or after treatment with glutamine. The rats were treated with glutamine (300 mg/kg b.w.) by gavage 24h before the administration of cisplatin (5mg/kg b.w., i.p.) and then sacrificed 24h after treatment with cisplatin. Glutamine significantly reduced (by about 48%) the clastogenicity of cisplatin in rat bone marrow cells. The antioxidant action of glutamine presumably modulates the clastogenic action of cisplatin.     

Effects of continuous and pulsatile PTH treatments on rat bone marrow stromal cells

Bone marrow stromal cells (MSCs) differentiation and proliferation are controlled by numerous growth factors and hormones. Continuous parathyroid hormone (PTH) treatment has been shown to decrease osteoblast differentiation, whereas pulsatile PTH increases osteoblast differentiation. However, the effects of PTH treatments on MSCs have not been investigated. This study showed continuous PTH treatment in the presence of dexamethasone (DEX) promoted osteogenic differentiation of rat MSCs in vitro, as demonstrated by increased alkaline phosphatase (ALP) activity, number of ALP expressing cells, and up-regulation of PTH receptor-1, ALP, and osteocalcin mRNA expressions. In contrast, pulsatile PTH treatment was found to suppress osteogenesis of rat MSCs, possibly by promoting the maintenance of undifferentiated cells. Additionally, the observed effects of PTH were strongly dependent on the presence of DEX. MSC proliferation however was not influenced by PTH independent of treatment regimen and presence or absence of DEX. Furthermore, our work raised the possibility that PTH treatment may modulate stem/progenitor cell activity within MSC cultures.     

Cytogenetic effects of extremely low frequency magnetic field on Wistar rat bone marrow

In this study, the genotoxic and cytotoxic potential of extremely low frequency magnetic fields (ELF-MF) was investigated in Wistar rat tibial bone marrow cells, using the chromosomal aberration (CA) and micronucleus (MN) test systems. In addition to these test systems, we also investigated the mitotic index (MI), and the ratio of polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs). Wistar rats were exposed to acute (1 day for 4 h) and long-term (4 h/day for 45 days) to a horizontal 50 Hz, 1 mT uniform magnetic field generated by a Helmholtz coil system. Mitomycin C (MMC, 2 mg/kg BW) was used as positive control. Results obtained by chromosome analysis do not show any statistically significant differences between the negative control and both acute and long-term ELF-MF exposed samples. When comparing the group mean CA of long-term exposure with the negative control and acute exposure, the group mean of the long-term exposed group was higher, but this was not statistically significant. However, the mean micronucleus frequency of the longer-term exposed group was considerably higher than the negative control and acutely exposed groups. This difference was statistically significant (p < 0.01). The results of the MI in bone marrow showed that the averages of both A-MF and L-MF groups significantly decreased when compared to those in the negative control (p < 0.001 and p < 0.01, respectively). No significant differences were found between the group mean MI of A-MF exposure with L-MF. We found that the average of PCEs/NCEs ratios of A-MF exposed group was significantly lower than the negative control and L-MF exposed groups (p < 0.001 and p < 0.01, respectively). In addition, the group mean of the PCEs/NCEs ratios of L-MF was significantly lower than negative control (p < 0.01). We also found that the MMC treated group showed higher the number of CA and the frequency of MN formation when compared to those in all other each groups (p-values of all each groups <0.01) and also MMC treated group showed lower MI and the PCEs/NCEs ratios when compared to those in all other each groups (p-values of all groups <0.01). These observations indicate the in vivo suspectibility of mammals to the genotoxicity potential of ELF-MF.     

Cytogenetic effects of extremely low frequency magnetic field on Wistar rat bone marrow

In this study, the genotoxic and cytotoxic potential of extremely low frequency magnetic fields (ELF-MF) was investigated in Wistar rat tibial bone marrow cells, using the chromosomal aberration (CA) and micronucleus (MN) test systems. In addition to these test systems, we also investigated the mitotic index (MI), and the ratio of polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs). Wistar rats were exposed to acute (1 day for 4h) and long-term (4h/day for 45 days) to a horizontal 50Hz, 1mT uniform magnetic field generated by a Helmholtz coil system. Mitomycin C (MMC, 2mg/kg BW) was used as positive control. Results obtained by chromosome analysis do not show any statistically significant differences between the negative control and both acute and long-term ELF-MF exposed samples. When comparing the group mean CA of long-term exposure with the negative control and acute exposure, the group mean of the long-term exposed group was higher, but this was not statistically significant. However, the mean micronucleus frequency of the longer-term exposed group was considerably higher than the negative control and acutely exposed groups. This difference was statistically significant (p<0.01). The results of the MI in bone marrow showed that the averages of both A-MF and L-MF groups significantly decreased when compared to those in the negative control (p<0.001 and p<0.01, respectively). No significant differences were found between the group mean MI of A-MF exposure with L-MF. We found that the average of PCEs/NCEs ratios of A-MF exposed group was significantly lower than the negative control and L-MF exposed groups (p<0.001 and p<0.01, respectively). In addition, the group mean of the PCEs/NCEs ratios of L-MF was significantly lower than negative control (p<0.01). We also found that the MMC treated group showed higher the number of CA and the frequency of MN formation when compared to those in all other each groups (p-values of all each groups <0.01) and also MMC treated group showed lower MI and the PCEs/NCEs ratios when compared to those in all other each groups (p-values of all groups <0.01). These observations indicate the in vivo suspectibility of mammals to the genotoxicity potential of ELF-MF.     

Effects of strontium on proliferation and differentiation of rat bone marrow mesenchymal stem cells

Strontium ranelate (SrR) was an effective anti-osteoporotic drug to increase bone formation and decrease bone resorption. However, reports about the effect of SR on osteoblastic and adipocytic differentiation from bone marrow mesenchymal stem cells (BMMSCs) are limited. The purpose of this study is to evaluate whether SrR affects the ability of BMMSCs to differentiate into osteoblasts or adipocytes. Rat BMMSCs were identified by flow cytometry and exposed to SR (0.1 and 1.0mMSr(2+)) under osteogenic or adipogenic medium for 1 and 2weeks. The proliferation and differentiation of BMMSCs were analyzed by MTT, alkaline phosphatase (ALP), Oil red O staining, quantitative real-time RT-PCR and Western blot assays. SrR significantly inhibited the proliferation, increased osteoblastic but decreased adipocytic differentiation of rat BMMSCs dose-dependently. In osteogenic medium, SrR increased the expression of ALP, the mRNA levels of Cbfa1/Runx2, bone sialoprotein, and osteocalcin by RT-PCR, and the protein levels of Cbfa1/Runx2 by Western blot. In adipogenic medium, SrR decreased the mRNA levels of PPARγ2, adipocyte lipid-binding protein 2 (aP2/ALBP), and lipoprotein lipase (LPL) by RT-PCR, and the protein expression of PPARγ in Western blot analysis. These results indicated that the effects of SrR to promote osteoblastic but inhibit adipocytic differentiation of BMMSCs might contribute to its effect on osteoporosis treatment.     

Sodium-dependent vitamin C transporter SVCT2: Expression and function in bone marrow stromal cells and in osteogenesis

Ascorbic acid (Vitamin C) has a critical role in bone formation and osteoblast differentiation, but very little is known about the molecular mechanisms of ascorbic acid entry into bone marrow stromal cells (BMSCs). To address this gap in knowledge, we investigated the identity of the transport system that is responsible for the uptake of ascorbic acid into bone marrow stromal cells (BMSCs). First, we examined the expression of the two known isoforms of the sodium-coupled ascorbic acid transporter, namely SVCT1 and SVCT2, in BMSCs (Lin ? ve Sca1 + ve) and bone at the mRNA level. Only SVCT2 mRNA was detected in BMSCs and bone. Uptake of ascorbic acid in BMSCs was Na⁺-dependent and saturable. In order to define the role of SVCT2 in BMSC differentiation into osteoblasts, BMSCs were stimulated with osteogenic media for different time intervals, and the activity of SVCT2 was monitored by ascorbic acid uptake. SVCT2 expression was up-regulated during the osteogenic differentiation of BMSCs; the expression was maximal at the earliest phase of differentiation. Subsequently, osteogenesis was inhibited in BMSCs upon knock-down of SVCT2 by lentivirus shRNA. We also found that the expression of the SVCT2 could be negatively or positively modulated by the presence of oxidant (Sin-1) or antioxidant (Ascorbic acid) compounds, respectively, in BMSCs. Furthermore, we found that this transporter is also regulated with age in mouse bone. These data show that SVCT2 plays a vital role in the osteogenic differentiation of BMSCs and that its expression is altered under conditions associated with redox reaction. Our findings could be relevant to bone tissue engineering and bone related diseases such as osteoporosis in which oxidative stress and aging plays important role.     

转基因抗矮花叶玉米对大白鼠骨髓细胞遗传毒性的影响

以SD大鼠为研究对象,研究了转基因抗矮花叶玉米和常规玉米对大白鼠骨髓细胞微核率与染色体畸变率的影响,以观察该转基因玉米对大白鼠可能产生的遗传毒理效应。实验结果表明：饲喂30%和50%转基因玉米日粮组的大白鼠骨髓细胞微核率和染色体畸变率与饲喂常规玉米相比均没有显著差异,而与阳性对照组之间存在极显著差异,这说明转基因玉米与常规玉米对大白鼠骨髓细胞均无遗传毒性。     

Hormonal changes affect the bone and bone marrow cells in a rat model

In this study, we used a rat model to investigate the effects of gonad hormones and replacement therapy on bone structure and the immune system. In the first phase of the study, 3- and 11-month-old F344 rats underwent ovariectomy (OVX) or were sham operated. Three months later, severe osteopenia was histologically observed in OVX rats of both age groups. The changes in the bone marrow structure of OVX rats included deterioration of cancellous bone that was associated with a remarkable increase of adipocyte cells. Furthermore, differential analyses for the expression of cell surface antigens by lymph-myeloid cells was studied using flow cytometry (FACS). The number of myeloid cells expressing ED-9(+) or CD-44(+) was similar in both age groups, and unaffected by OVX. However, an augmentation of T-lymphoid cells expressing CD4(+), CD5(+), or both, were observed with age, as well as after OVX. In the second phase of the study, 11-month-old rats were divided into five experimental groups: sham-operated, OVX, and OVX treated with sustained-release pellets of 17beta-estradiol (OVX-E), progesterone (OVX-P), or both (OVX-E/P). Hormone replacement therapy maintained low physiological levels, and rats were tested 12 weeks after treatment initiation. Administration of 17beta-E, with or without the addition of progesterone, prevented the rise of T lymphoid cells observed in OVX rats, whereas progesterone alone had no effect. In agreement with findings from the first phase, neither OVX nor replacement therapy affected the myeloid cells expression of ED-9 or CD-44. In summary, the cellular changes in the bone marrow of OVX rats were associated with an increase in adipocytes that was correlated with bone atrophy. An augmentation of T-lymphopoiesis was noted with increase in age or after OVX. This increase was reversed to baseline levels by 17beta-E treatment.     

Erythropoietin effects on iron metabolism in rat bone marrow cells

This paper describes a study of the incorporation of ^{5 9}Fe from ^{5 9}Fe-labelled rat transferrin into rat bone marrow cells in culture. ^{5 9}Fe was found in both stroma and cytoplasm of marrow cells, and the cytoplasmic ^{5 9}Fe separated by polyacrylamide gel electrophoresis, into ferritin, haemoglobin and a low molecular weight fraction.The incorporation of ^{5 9}Fe into all three cytoplasmic fractions, but not into the stroma, increased progressively with time. Erythropoietin stimulated the increase of ^{5 9}Fe in ferritin within 1 h, the earliest time examined, and more than 3 h later in the stroma and haemoglobin.A proportion of the ⁵⁹Fe incorporated into the stroma and low molecular weight iron fractions during a 1 h incubation with ⁵⁹Fe-labelled transferrin was mobilised into ferritin and haemoglobin during a subsequent 4-h “cold-chase”. Erythropoietin, when present during the “cold-chase”, did not influence these ⁵⁹Fe fluxes. The erythropoietin stimulation of ⁵⁹Fe incorporation into ferritin, one of the earliest erythropoietin effects to be recorded, was therefore considered to be due to an increase of ⁵⁹Fe uptake by the hormone-responsive cells rather than a direct effect on ferritin synthesis.20-h cultures containing erythropoietin when incubated with ⁵⁹Fe-labelled transferrin for 4 h, showed dose-related erythropoietin stimulation of ⁵⁹Fe incorporation into haemoglobin only.In the presence of 10 mM isonicotinic acid hydrazide, ⁵⁹Fe incorporation into haemoglobin was inhibited, as in reticulocytes (Ponka, P. and Neuwirt, J. (1969) Blood 33, 690–707), while that into the stroma, ferritin and low molecular weight iron fractions, was stimulated; there were no reproducible effects of erythropoietin.     

The effect of bleomycin on rat bone marrow cells.

Experiments were carried out to determine the cytogenetic effects of the antibiotic bleomycin (BLM) in rats using the bone marrow system. A total of eighteen male and eighteen female Sprague-Dawley rats were injected with varying concentration of BLM, over varying periods of time. The results revealed that at low concentrations BLM showed no alteration in the ploidy or the morphology of rat chromosomes. This however, was not the case when the dose or administration period was increased.     

Asialogangliosides as differentiation markers of rat erythropoietic and granulopoietic cells in rat bone marrow. Flow cytometric analysis of rat bone marrow cells using anti-asialoganglioside antibodies

Flow cytometric analysis using anti-glycolipid antiserum was used on rat bone marrow cells to determine the relation between the glycolipid species expressed on cell surfaces and cell differentiation. Four kinds of antibodies against gangliotriaosylceramide (Gg3Cer), gangliotetraosylceramide (Gg4Cer), fucogangliotetraosylceramide (IV2 alpha Fuc-Gg4Cer) and IV3 alpha Gal-fucogangliotetraosylceramide (IV3 alpha GalIV2 alpha Fuc-Gg4Cer, blood group B lipid) were used. The cells sorted out by each anti-glycolipid antiserum were stained with May-Grünwald-Giemsa reagent and identified by microscopy. In the erythropoietic group, only polychromatic erythroblasts had these four glycolipids on their cell surfaces; none appeared on differentiated erythrocytes. These glycolipids were expressed during the early stages of immature granulocytes, especially in the promyelocyte and myelocyte stages of eosinophilic and neutrophilic granulocytes. Very limited populations of lymphocytes were sorted out as asialoganglioside-expressing cells. We concluded that asialogangliosides are useful differentiation markers for the erythropoietic and granulopoietic cells of rat bone marrow, and that anti-asialoganglioside antibody-flow cytometry is a very useful technique with which to isolate immature granulocytes and erythropoietic cells from rat bone marrow cells.     

Glycosphingolipid biosynthesis through asialogangliosides in rat bone marrow cells

Glycolipid biosynthesis in rat bone marrow cells has been studied with reference to four kinds of glycosyltransferases catalyzing the transfer of N-acetylgalactosamine, galactose, N-acetylneuraminic acid, and fucose to each glycolipid acceptor. It was demonstrated that glycosyltransferase activities which synthesize galactosylglucosylceramide (CDH) from glucosylceramide (CMH), N-acetylgalactosaminylgalactosylglucosylceramide (GA2) from CDH, galactosyl-N-acetylgalactosaminylgalactosylglucosylceramide (GA1) from GA2 and N-acetylneuraminylgalactosyl-N-acetylgalactosaminylgalactosylglucosylceramide (Gm1b) from GA1 were all present in rat bone marrow cell homogenate. Fucosyltransferase activity catalyzing the transfer of fucose from GDP-fucose to GA1 was also recognized in the cell homogenate. Neutral glycolipid extracted from rat bone marrow cells was analyzed by thin layer chromatography and glycosidase treatments. The presence of glycolipids corresponding to GA2, GA1 and fucolipid was demonstrated. From these results, it was concluded that the biosynthesis of glycolipid through asialogangliosides is a major biosynthetic route in rat bone marrow cells.     

Effects of aluminum on erythroidal cells in bone marrow in rats

The study has been carried out on Wistar rats. The aim of the present study was to trace the effect of aluminum on erythroidal cells in bone marrow in rats. The number of proerythroblast after 10 days of experiment with aluminum slowly decreased up to 80 days of experiments. However, the number of basophilic erythroblasts after 10 days insignificantly increased but after 20 days gradually decreased up to 80 days of experiments. The bone marrow polichromatic erythroblasts after 10 days of experiment slightly decreased, however after 20, 40 and 80 days of experiments the values decreased significantly. The quality of orthochromatic erythroblasts after 10 days of experiments dropped and after 20, 40 and 80 days of experiments significantly decreased compared to the control value. Aluminum also brings about histological changes in the bone marrow. The statistical significant reductions of hemoglobin and hematocrit levels were found in the aluminum exposed rats.