Effect of erythrocytic G2-chalone on the erythrokinetics in mice]

It was shown that erythrocytic inhibitor (G2-cheilon) acted both on the proliferating and on differentiated cells of the erythroid series of the mouse bone marrow. The effect of cheilon was expressbd as soon as 3 hours after its administration and lasted for from 8 to 48 hours, depending on the extent of cell differentiation. In case of a single cheilon administration, despite significant erythropoiesis disturbances, erythrocyte count determined 8 to 12 days later persists within the control level. Repeated administration of cheilon was accompanied by a fall of the erythrocyte count at later periods of the experiment.     

Genotoxicity studies on the azo dye Direct Red 2 using the in vivo mouse bone marrow micronucleus test.

The clastogenicity of the azo dye Direct Red 2 (DR2) has been investigated using the murine bone marrow micronucleus assay. A potent dose-dependent response was observed following oral gavage of DR2 up to 4 mg/kg, after which significant toxicity to the erythroid compartment was observed. The route of administration had a significant effect on the frequency of micronucleus formation: intraperitoneal injection was approximately two-fold less clastogenic than the equivalent dose delivered orally (p<0.05). The requirement for activation of DR2 by intestinal microflora was indicated by the fact that mice given acid-treated water prior to administration of DR2 showed a significant reduction (40%; p<0.001) in micronucleated polychromatic erythrocyte formation. The implications of these findings for the health and safety of occupationally exposed workers are discussed.     

Assessment of the genotoxicity of propineb in mice bone marrow cells using micronucleus assay

Propineb, a dithiocarbamate fungicide, is commonly used for the control of disease in a wide range of crops in agriculture. The genotoxic effects of commercial formulation of propineb in bone marrow cells of mice was investigated in vivo by micronucleus (MN) assay. The three different concentrations of propineb (12.5, 25 and 50 μg/mL; 0.01 mL per gram) were injected intraperitoneally (i.p.) to mice for 24 and 48 h. The results of the MN assay indicated that propineb induced a significant increase in frequency of micronucleated polychromatic erythrocytes (MNPCE) at 25 and 50 μg/mL concentrations for 24 h and at the highest (50 μg/mL) concentration for 48 h when compared with negative control. Also significant reduction for the polychromatic erythrocyte/normochromatic erythrocyte (PCE/NCE) ratio which is indicative for bone marrow cytotoxicity was observed at the same concentrations for 24 and 48 h. These results lead us to the conclusion that propineb may have genotoxic and cytotoxic potential due to induction in the frequency of MN and a reduction in PCE/NCE ratio in the bone marrow cells of mice.     

Effect of erythrocyte breakdown products on mast cells and erythropoietin formation]

Experiments were conducted on CBA mice and albino rats. A study was made of the effect of erythrocyte destruction products (EDP) on the content of hemopoietic colony-forming units (CFU), differentiation of stem cells and the erythropoietin production. It was shown that 3 or 4 EDP injections to normal mice or to lethally irradiated (1000 rad) mice after the transplantation of bone marrow cells caused no changes in the CFU level of stem cells differentiation. In case of a daily (for 3 days) administration of EDP to mice before the irradiation (1000 rad) and bone marrow transplantation there was observed an increase of the colonies count in the recipients' spleen on account of the erythroid colonies. EDP injection caused no changes in the erythropoietic activity of the blood serum. A possible role of erythrocyte destruction products in the mechanism of erythropoiesis autoregulation is discussed.     

Proliferation and splenic migration of mouse hematopoietic stem cells following a single injection of Mycoplasma arthritidis

The effect of a single injection of live M. arthritidis microorganisms on the bone marrow and spleen CFU-S populations was assessed. One of the principal findings is that marrow CFU-S are recruited into cell cycle (as determined by hydroxyurea kill) early after M. arthritidis administration and stay in the cycle for at least 2 weeks thereafter. The peak level of cycling value (47%) was observed on day 4. The duration of increased CFU-S cycling activity was shown to coincide with a time period during which a significant rise in the number of endogenous CFU-S was maintained. The other important finding is that splenic seeding efficiency ("f-factor") declines by 56% one day following M. arthritidis administration. The latter effect could be attributed to the binding of mycoplasmas to the surface of CFU-S as specific rabbit antiserum against M. arthritidis incubated in vitro with the bone marrow cells of infected donor mice caused an up to 48% reduction in the in vivo colony-forming ability of CFU-S.     

兔再生肝提取物对骨髓细胞增殖,分化的影响

兔再生肝提取物（ＲＲＬＥ）中含一种对骨髓有明显影响的造血因子。通过给正常Ｂａｌｂ／ｃ小鼠体内注射ＲＲＬＥ,１天后骨髓有核细胞总数有意义减少,同时外周血和脾红髓内出现造血祖细胞,并伴贫血。取实验第２天脾细胞培养,ＣＦＵ—ｓ数明显升高,为混合性克隆形成单位。第４天后骨髓活跃增殖,产生以中性粒细胞系为主的大量骨髓细胞。血网织红细胞与白细胞值有意义升高,ＲＢＣ值于第９天恢复正常。上述结果提示ＲＲＬＥ中含有与其它造血因子作用不同的细胞因子。     

Simian immunodeficiency virus inhibits bone marrow hematopoietic progenitor cell growth.

The pathogenic mechanisms underlying the depressed hematopoietic functions seen in human immunodeficiency virus-infected individuals were explored in rhesus monkeys infected with the simian immunodeficiency virus of macaques (SIVmac). Bone marrow hematopoietic progenitor cell colony formation, both granulocyte/macrophage (CFU-GM) and erythrocyte (BFU-E), was shown to be decreased in number in SIVmac-infected rhesus monkeys. SIVmac was readily isolated from bone marrow cells of infected monkeys and was shown to be harbored in macrophages rather than T lymphocytes. The in vitro infection of normal bone marrow cells by SIVmac inhibited colony formation. A striking in vivo correlation between increased SIVmac load in bone marrow cells and decreased hematopoietic progenitor cell colony growth was also shown. Finally, inhibition of SIVmac replication in bone marrow macrophages resulted in increased progenitor cell colony growth from bone marrow cells. These results suggest that the infection of bone marrow macrophages by the acquired immunodeficiency syndrome (AIDS) virus may contribute to depressed bone marrow hematopoietic progenitor cell growth. Moreover, inhibition of AIDS virus replication in these macrophages might induce significant improvement in hematopoietic function.     

The effect of splenectomy on bone marrow haematopoiesis in mice.

Splenectomy was performed in strain H mice. Erythrocyte macrocytosis and an increase in the reticulocyte, leucocyte and thrombocyte count were found in the peripheral blood of splenectomized animals; only the erythrocyte count fell in the first 3 weeks after splenectomy. Changes in the myelogram during the first weeks after splenectomy were characterized by an increase in the proportion of cells of the erythrocytic and lymphocytic series. The stem cell count in the bone marrow (determined after Till and McCulloch) was slightly elevated on the 8th day after splenectomy, but in subsequent weeks was rather lower than the control group values. Whatever the post-splenectomy interval at which bone marrow was taken from splenectomized mice, there was no significant difference in the transplantation effect of bone marrow cells on white and thrombocyte haematopoiesis. Bone marrow transplantation was found have a stimulant effect only on the reticulocyte count and the sooner bone marrow was collected after splenectomy, the more pronounced the effect. Changes in the myelogram and splenogram of irradiated mice to which the bone marrow cells of splenectomized mice had been transplanted were relatively small.     

Hemopoietic environment necessary for an early stage in differentiation of antibody-forming cells: effect of cortisol

Treatment of adult mice with cortisol decreased the number and frequency of bone marrow precursors of anti-sheep erythrocyte hemolytic plaque-forming cells (P-PFC) and marrow “lymphocytes.” However, the more primitive progenitors of P-PFC in marrow were not affected. Treatment of prospective recipients of marrow grafts with cortisol impaired the generation of P-PFC by transplanted primitive progenitor cells. Differentiation with proliferation of P-PFC into mature PFC was less dramatically affected by cortisol. P-PFC were not apparently suppressed directly, since the fall-off of P-PFC did not occur during the first day after administration of cortisol. Thus, cortisol impairs the generation of P-PFC by altering a hemopoietic inductive environment necessary for this step in differentiation of immunocompetent cells.     

Genotoxicity of two anticancer drugs,gemcitabine and topotecan,in mouse bone marrow in vivo

In this study, the genotoxic effects of gemcitabine and topotecan were investigated in mouse bone marrow cells using the micronucleus and chromosomal aberration test systems. Gemcitabine increased the frequency of micronuclei, particularly at the median dose for the 24-, 36-, and 48-h sampling intervals. It had cytotoxic effects on the bone marrow and decreased the polychromatic/normochromatic erythrocyte ratio dose-dependently for all sampling intervals. Gemcitabine significantly decreased the mitotic index at the 24-h time point. It increased the number of abnormal cells and induced a significant increase in total chromosomal aberrations. For the 6-h sampling time, gemcitabine neither induced chromosomal aberrations nor reduced the mitotic index. Topotecan also induced high levels of micronuclei, particularly for the 24- and 36-h sampling times and it decreased the polychromatic/normochromatic erythrocyte ratio for all sampling intervals, which is indicative of bone marrow cytotoxicity. The bone marrow metaphase analysis showed that topotecan significantly elevated the number of abnormal metaphases and total chromosomal aberrations at 6 and 24h, in a dose-dependent manner. It also decreased the mitotic index for both sampling intervals. In conclusion, the results of this study indicate that the two chemotherapeutics gemcitabine and topotecan have cytotoxic and genotoxic effects in mouse bone marrow.     

Radioprotection of mice with interleukin-1: relationship to the number of erythroid and granulocyte-macrophage colony-forming cells

This report presents the results of an investigation of changes in the number of erythroid and granulocyte-macrophage colony-forming cells (GM-CFC) that had occurred in tissues of normal B6D2F1 mice 20 h after administration of a radioprotective dose (150 ng) of human recombinant interleukin-1 (rIL-1). Neutrophilia in the peripheral blood and changes in the tissue distribution of GM-CFC demonstrated that cells were mobilized from the bone marrow in response to rIL-1 injection. For example, 20 h after rIL-1 injection marrow GM-CFC numbers were 80% of the numbers in bone marrow from saline-injected mice. Associated with this decrease there was a twofold increase in the number of peripheral blood and splenic GM-CFC. Also, as determined by hydroxyurea injection, there was an increase in the number of GM-CFC in S phase of the cell cycle in the spleen, but not in the bone marrow. Data in this report suggest that when compared to the spleen, stimulation of granulopoiesis after rIL-1 injection is delayed in the bone marrow. Also, the earlier recovery of GM-CFC in the bone marrow of irradiated mice is not dependent upon an increase in the number of GM-CFC at the time of irradiation.     

Cytogenetic damage of bone marrow cells produced by chronic alcohol consumption

Pair-feeding of rats with nutritionally adequate liquid diets containing 36% of total energy either as ethanol or as additional carbohydrate (in the controls) resulted in blood ethanol concentrations similar to those observed in alcoholics. Alcohol feeding for six weeks increased the frequency of micronuclei in bone marrow erythrocytes, an index of chromosomal damage in precursor cells. This was associated with bone marrow hypoplasia and erythrocyte macrocytosis, alterations commonly found in alcoholics. By contrast, acute ethanol administration produced no changes in the bone marrow. Cytogenetic damage of stem cells could lead to alterations persisting after alcohol withdrawal beyond the life span of effector cells.     

Genotoxicity of paraquat: micronuclei induced in bone marrow and peripheral blood are inhibited by melatonin

The ability of melatonin to influence paraquat-induced genotoxicity was tested using micronucleated polychromatic erythrocytes as an index of damage in both bone marrow and peripheral blood cells of mice. Melatonin (10 mg/kg) or an equal volume of saline were administered intraperitoneally (ip) to mice 30 min prior to an ip injection of paraquat (20 mg/kgx2), and thereafter at 6-h intervals until the conclusion of the study (72 h). The number of the micronucleated polychromatic erythrocytes increased after paraquat administration both in peripheral blood and bone marrow cells. Melatonin administration to paraquat-treated mice significantly reduced micronuclei formation in both peripheral blood and bone marrow cells; these differences were apparent at 24, 48 and 72 h after paraquat administration. The induction of micronuclei was time-dependent with peak values occurring at 24 and 48 h. The reduction in paraquat-related genotoxicity by melatonin is likely due in part to the antioxidant activity of the indole. We did not observe effects of melatonin over paraquat in paraquat+melatonin groups incubated at 0, 60 and 120 min. Mitomycin C, which was used as a positive control, also caused the expected large rises in micronuclei in both bone marrow and peripheral blood cells at 24, 48 and 72 h after its administration.     

Elimination of senescent neutrophils by TNF-related apoptosis-inducing [corrected] ligand

Neutrophils are phagocytic effectors which are produced in the bone marrow and released into the circulation. Thereafter, they are either recruited to sites of inflammation or rapidly become senescent, return to the bone marrow, and undergo apoptosis. Stromal cell-derived factor 1 (SDF-1) coordinates the return of senescent neutrophils to the bone marrow by interacting with CXCR4 that is preferentially expressed on senescent neutrophils. We demonstrate that CXCR4 ligation by SDF-1 or other CXCR4 agonists significantly increases the expression of both TNF-related apoptosis-inducing [corrected] ligand (TRAIL) and of the death-inducing TRAIL receptors on neutrophils, which confers an acquired sensitivity to TRAIL-mediated death and results in TRAIL-dependent apoptosis. In vivo administration of TRAIL antagonists results in neutrophilic accumulation within the bone marrow and a reduction in neutrophil apoptosis; conversely recombinant TRAIL administration reduced neutrophil number within bone marrow. Thus, SDF-1 ligation of CXCR4 causes the parallel processes of chemotaxis and enhanced TRAIL and TRAIL death receptor expression, resulting in apoptosis of senescent neutrophils upon their return to the bone marrow.     

The effects of colcemid on mouse bone marrow.

Following Colcemid administration, mitoses accumulate preferentially in the subendosteal region of the bone marrow of the mouse. This finding suggests that the most rapidly proliferating cells are localized to the subendosteal region, and complements previous radioautographic studies which have demonstrated a corresponding labelling gradient in the marrow. Quantitative estimates of cell cycle time by the stathmokinetic method were precluded by the presence of significant Colcemid induced interphase cell loss. Colcemid also affected cell differentiation in the marrow. Following Colcemid administration there was a fall in mature granulocytes in the marrow, and a concommitant rise in marrow megakaryocytes.     

Injections of leptin into rat ventromedial hypothalamus increase adipocyte apoptosis in peripheral fat and in bone marrow

The accumulation of fat cells (adipocytes) in bone marrow is now thought to be a factor contributing to age-related bone loss. Women with osteoporosis have higher numbers of marrow adipocytes than women with healthy bone, and bone formation rate is inversely correlated with adipocyte number in bone tissue biopsies from both men and women. Adipogenic differentiation of bone marrow stromal cells increases with age, but the factors regulating populations of mature adipocytes are not well understood. Leptin is thought to regulate adipose tissue mass via its receptors in the ventromedial hypothalamus (VMH). We have therefore tested the hypothesis that stimulation of leptin receptors in the VMH regulates adipocyte number in bone marrow. Results indicate that unilateral twice-daily injections of leptin into the rat VMH for only 4 or 5 days cause a significant reduction in the number of adipocytes in peripheral fat pads and bone marrow and indeed eliminate adipocytes almost entirely from bone marrow of the proximal tibia. Osteoblast surface is not affected with leptin treatment. Apoptosis assays performed on bone marrow samples from control and treated rats have revealed a significant increase in protein concentration of the apoptosis marker caspase-3 with leptin treatment. We conclude that stimulation of leptin receptors in the VMH significantly decreases the adipocyte population in bone marrow, primarily through apoptosis of marrow adipocytes. Elimination of marrow adipocytes via this central pathway may represent a useful strategy for the treatment and prevention of osteoporosis.     

The migration of lymphocytes across specialized vascular endothelium. IV. Prednisolone acts at several points on the recirculation pathways of lymphocytes

Radioactively labelled thoracic duct lymphocytes from syngeneic rat donors were injected iv into recipients which had been given a continuous iv infusion of prednisolone at 1 mg/hr for 15–18 hr previously. The tissue distribution and recirculation into lymph of the labelled lymphocytes were compared quantitatively in the prednisolone-treated and control recipients by scintillation counting and autoradiography. The most prominent effect of prednisolone was to retard recirculating lymphocytes within the tissues to which they are normally distributed by the blood, namely the bone marrow, the spleen, and the lymph nodes. Although lymphocyte traffic was almost completely frozen by prednisolone, recirculating lymphocytes were not killed. A second effect of prednisolone was to impair the influx of lymphocytes from the blood into lymph nodes. Different groups of lymph nodes varied in the extent to which prednisolone inhibited the entry of lymphocytes, and previous antigenic stimulation completely exempted lymph nodes from this inhibition. Lymphocytes took a longer time to cross the walls of high endothelial venules in the lymph nodes of prednisolone-treated rats. A third effect of prednisolone was to increase the rate at which lymphocytes entered the bone marrow from the blood by crossing sinusoidal endothelium.     

Hematologic and immunologic effects of pulsed microwaves in mice

Mice were exposed in the far field in an anechoic chamber to 2,880-MHz pulsed microwaves 3 to 7.5 h daily, 5 days/week for 60 to 360 h. Three experiments were performed at average power densities of 5 mW/cm2 and six at 10 mW/cm2, corresponding to averaged specific absorption rates (SARs) of 2.25 and 4.50 mW/g, respectively. Each experiment consisted of eight mice, with a concurrently sham-exposed group of eight. In two of three studies at 5 mW/cm2, there was a significant increase in bone marrow cellularity in the microwave-exposed groups compared to the sham-exposed groups. Significant differences were occasionally seen in erythrocyte, leukocyte, and platelet values from microwave-exposed groups, but were not consistently observed. In one of six groups exposed at 10 mW/cm2, mean bone marrow cellularity was reduced significantly in the microwave-exposed mice; in another group, the lymphocyte count was increased. In only one exposure (10 mW/cm2 for 360 h) was any significant effect noted on serum proteins: a reduction to 5.1 +/- 0.3 g/dl in the exposed versus 5.6 +/- 0.4 g/dl in the sham-exposed mice. This was due to a decrease in alpha and beta globulins, with no effect on albumin or gamma globulin concentrations. No effect on bone marrow granulocyte/macrophage colony-forming units (CFU) was revealed following exposure of mice to pulsed microwaves at 5 mW/cm2. In one of four exposures at 10 mW/cm2, there was a significant increase in CFU-agar colonies. No significant effects of exposures at 10 mW/cm2 were observed on in vivo and in vitro assays of cell-mediated immune functions. No exposure-related histopathologic lesions were found from examination of several tissues and organs. Results of these series of exposures of mice at SARs of 2.25 and 4.50 mW/g indicated no consistent effects on the hematologic, immunologic, or histopathologic variables examined.     

THE EFFECTS OF COLCEMID ON MOUSE BONE MARROW

Following Colcemid administration, mitoses accumulate preferentially in the subendosteal region of the bone marrow of the mouse. This finding suggests that the most rapidly proliferating cells are localized to the subendosteal region, and complements previous radioautographic studies which have demonstrated a corresponding labelling gradient in the marrow. Quantitative estimates of cell cycle time by the stathmokinetic method were precluded by the presence of significant Colcemid induced interphase cell loss. Colcemid also affected cell differentiation in the marrow. Following Colcemid administration there was a fall in mature granulocytes in the marrow, and a concommitant rise in marrow megakaryocytes.     

Immunocytochemical analysis of apoptotic bone marrow cells after treatment of mice with WR-2721 and chemotherapeutic drugs

The effects of the aminothiol WR-2721 (Amifostine) and the chemotherapeutic drugs, cyclophosphamide (CP) and cisplatin (CDDP) on induction of apoptosis in bone marrow cells of adult male Swiss mice were studied. The mice received intraperitoneal injections of WR-2721 (400 mg/kg), cyclophosphamide (200 mg/kg), and cisplatin (10 mg/kg). WR-2721 was administered alone, or 30 min before treatment of mice with CP or CDDP. The number of apoptotic bone marrow cells was determined at 7 h and 24 h after the agent(s) administration. The In Situ Cell Death Detection Kit, AP based on TUNEL technique, and Fast Red Substrate System were used for microscopic analysis of immunocytochemically stained apoptotic cells. Application of cyclophosphamide and cisplatin resulted in a distinct increase of the number of apoptotic cells in the mouse bone marrow. After treatment of mice with WR-2721 prior to administration of CP or CDDP, as compared to the chemotherapeutic treatment only, the tendency to a decrease--albeit statistically insignificant--in the number of apoptotic cells was observed. Application of WR-2721 alone, without subsequent administration of the chemotherapeutic agents caused an inconsiderable increase in the number of apoptotic cells. The degree of apoptotic DNA cleavage in cells of the mouse bone marrow varied depending on the agent(s) given and the time interval after the drug administration.