Analysis of cadmium and lead: their immunosuppressive effects and distribution in various organs of mice

Chronic exposure (3.5 mo) of mice to cadmium (Cd), lead (Pb), or a cadmium-lead mixture at a concentration of 1 ppm in drinking water induced a highly significant inhibition of antibody response to human serum. The highest immunosuppression (84.4%) was induced by the Cd-Pb mixture, whereas Cd caused the lowest immunosuppression (53.6%). The body burden of Cd and Pb in various organs was investigated in the four groups of mice by atomic absorption spectrometry. The highest level of Cd was found in the kidney of the Cd-treated group, and the highest level of Pb was found in the liver of the Pb- and Cd-Pb-treated groups. It is concluded that when mice are exposed concurrently to Cd and Pb, they develop synergistic immunosuppression. Analysis of Cd levels using atomic absorption spectrometry revealed that it was distributed in the following order: kidney > liver > spleen > heart, whereas Pb was distributed in the following order: liver > kidney > spleen > heart.     

Pathogenicity of Hansenula anomala in a model of immunocompromised mice

Systemic infections caused by opportunistic fungi have shown an increased frequency in the past 10 years, particularly in immunocompromised patients. Hansenula anomala is an ascosporogenous yeast of the Ascomycetes class found in the skin, throat, and digestive tract transient normal flora. This study was conducted to compare the pathogenicity of H. anomala and Candida albicans in a model of immunocompromised mice. Thirty-eight Swiss mice were divided into two groups as follows: 30 animals received an intraperitoneal (i.p.) injection of cyclophosphamide (200 mg/kg) four days before the induction of infection with H. anomala (1 × 10⁶ yeasts/mL), and 8 animals received 100 mg/kg of cyclophosphamide at 3-day intervals during 3 weeks before inoculation of 1 × 10⁷ yeasts/mL. All animals were treated with amoxicillin/clavulanic acid (40 mg/kg) four days before induction of infection. A group of mice inoculatd with C. albicans (ATCC 64548) served as control. Tissue samples from the lung, spleen, liver, and kidney for histological and mycologic studies were obtained at necropsy. In each animal, the number of viable yeasts per gram of kidney was determined. The organs most frequently infected by H. anomala were the kidneys and the liver (20%), and the lung (10%). However, in conditions of sustained immunosuppression, H. anomala was found in 65.5% of the organs examined. It is concluded that in an experimental model of immunocompromised mice, the pathogenicity of H. anomala was low. This revised version was published online in August 2006 with corrections to the Cover Date.     

小鼠低剂量辐射损伤模型的初步研究

目的:对小鼠低剂量辐射损伤模型进行初步研究并筛选敏感检测指标.方法:实验分7组,1组为正常组,其余6组用XHA600直线加速器射线照射,每组取一部分小鼠于照射后2、4、8、16h测定红细胞(RBC)、白细胞(WBC)、血小板(PLT)和血红蛋白(HGB)含量;测定小鼠肝脏和脾脏重量及其组织中的超氧化合物歧化酶(SOD)和丙二醛(MDA)含量;剩余小鼠于4周后观察骨髓切片中血细胞变化.结果:照射后4h测定血常规,发现累积辐射0.4Gy组小鼠RBC有降低趋势,WBC、HGB显著降低,PLT显著升高;肝脏、脾脏的湿质量显著降低;小鼠肝脏组织中MDA的含量显著升高、SOD的活力显著降低;4周后小鼠骨髓细胞的病理改变与单次照射剂量相关,单次较大剂量(如0.6Gy)照射对骨髓细胞影响较大,在4周观察期不能自身恢复,而多次累积照射对骨髓细胞病理改变较小.结论:小鼠低剂量辐射损伤模型的最佳造模剂量为累积照射0.4Gy即每次照射100mGy,间隔一天,连续照射4次.     

The stability of methyl and ethyl phosphotriesters in DNA in vivo

C57BL male mice were injected with N-methyl-N-nitrosourea (MNUA) or N-ethyl-N-nitrosourea (ENUA) and the concentration of alkyl phosphotriesters in the DNA of lung, liver, brain, kidney, spleen and thymus determined from the extent of degradation induced in isolated DNA by alkali. The same total dose of reagent was given either as a single injection (i.p.) or by weekly injections carried out over 5-20 weeks. Methyl phosphotriesters induced in liver, lung and kidney by the single injection were lost with a half-life of about 7 days, in brain the loss was more rapid, t1/2 = 2-3 days. During the multiple injections the observed t1/2 was 16 days. Ethyl phosphotriesters formed in the DNA of lung, liver, kidney and brain were much more stable than the methyl derivatives, t1/2 = 10-15 weeks. Phosphotriesters formed in the DNA of spleen and thymus disappeared very quickly after the single injection presumably as a result of dilution due to DNA replication. No accumulation of phosphotriesters occurred in the DNA of these tissues during the multiple injections. The general pattern of the results suggests that phosphotriesters are not excised by cellular repair systems.     

Presence of Schistosoma mansoni antigens in liver, spleen and kidney of infected mice: a sequential study

In the present study the kinetics of the uptake and deposition of Schistosoma mansoni antigens in liver, spleen and kidney of S. mansoni infected Swiss mice have been investigated in relation to duration of infection and infection dose (50, 100, 200 cercariae). The presence of antigen was studied with a direct immunofluorescence reaction on frozen sections of the organs, using a number of fluorescein isothiocyanate (FITC)-labeled antisera produced against various antigen preparations isolated from different life-cycle stages of the parasite. The presence of antigen was demonstrable with two of the antisera, directed against the circulating anodic antigen (CAA) and against total soluble egg antigen (SEA). CAA was demonstrable from 1 week post infection (p.i.) onwards in Kupffer cells in the liver, from 2-3 weeks p.i. onwards in macrophages in the marginal zones in the spleen and from 3 weeks onwards in kidney glomeruli. Immunofluorescence reactions on CAA in kidney glomeruli, however, were only weak positive until 12 weeks p.i., whereafter strong positive reactions were found. SEA was demonstrable from 5 weeks p.i. onwards in Kupffer cells in the liver and from 4 weeks p.i. onwards in macrophages of the spleen. In contrast to CAA, SEA was not detectable in kidney glomeruli.     

乳酸菌源有机硒对肝损伤小鼠脾脏脂质过氧化和NK细胞活性的保护效应研究

本文通过研究乳酸茵源有机硒干预CCl4致肝损伤小鼠脾脏NK细胞活性和脂质过氧化反应的变化,探讨该有机硒在抗损伤保护过程中的效应及其机制。分别选用60只健康成年小鼠,雌雄对半,随机分成对照组(C组),有机硒组(Se组),CCl4组、CCl4-有机硒保护组(CCl4-Se组),每组15只。通过腹腔注射CCl4诱发肝损伤后,分别在第2、4周检测脾脏NK细胞活性及其组织匀浆GSH—Px、CAT、SOD活性和MDA含量变化。结果显示,在整个实验期内,C组、Se组和CCl4-Se组脾组织匀浆GSH—Px、CAT和SOD活性均高于或明显高于CCl4组,Se和CCl4-Se组与C组比较除SOD活性在第4周有明显升高外均差异不显著;CCl4组小鼠脾脏MDA含量均显著高于C组、Se组和CCl4-Se组,而CCl4-Se组与C组接近,Se组较CCl4-Se组和C组低;Se组NK细胞活性最高,第4周明显高于C组,CCl4组最低且低于或明显低于CCl4-Se、Se和C组,CCl4-Se组与C组无明显差异。结果提示,乳酸茵源有机硒能够提高正常机体抗氧化能力,在干预肝损伤过程中,可以通过改善和提高脾组织抗氧化酶活性及NK细胞活性发挥积极有效的作用。     

Experimental study on interactions between selenium and tin in mice

The organ distributions of tin and selenium, and their excretion into urine and feces, were determined in mice. There were four groups; (A) control, (B) Sn (5 μmol/kg/d) ip injection, (C) Se (5 μmol/kg/d) sc injection, and (D) Sn plus Se (5 μmol/kg/d, each). Animals received injections once a day for 12 consecutive days. The results were the following (1) Simultaneous injection of Sn and Se enhanced accumulation of both elements in the body, i.e., in group B, 14.1% of the total injected amount of Sn was excreted into urine and feces; in group C, 46.2% of total injected Se was excreted into urine and feces; in group D, 10.9% of total Sn and 37.5% of total Se were found in excreta. (2) Large amounts of Sn were found in bone, liver, spleen, and kidney in group B. When Se was administered jointly with Sn, the concentrations of Sn in bone and liver were suppressed, whereas those in spleen and pancreas were increased. (3) The effects of Se-injections at this dose on concentrations of Se in organs were small. (4) In plasma, chemical reduction of selenite by stannous chloride was not observed.     

Combined effect of vanadium(V) and chromium(III) on lipid peroxidation in liver and kidney of rats

Since chromium(III) was demonstrated to have antioxidative action, we have decided to study the effect of this element on V-induced LPO in liver and kidney of rats. Outbred 2-month-old, albino male Wistar rats received daily, for a period of 12 weeks: group I (control), deionized water to drink; group II, sodium metavanadate (SMV) solution at a concentration of 0.100mgV/mL; group III, chromium chloride (CC) solution at a concentration of 0.004mgCr/mL and group IV, SMV-CC solution at a concentration of 0.100mgV and 0.004mgCr/mL. The particular experimental groups took up with drinking water about 8.6mgV/kg b.w./24h (group II), 0.4mgCr/kg b.w./24h (group III), 9mgV and 0.36mgCr/kg b.w./24h (group IV). The V- or Cr-treated groups had higher concentrations of these two elements in liver and kidney compared to the controls. The administration of vanadium alone caused a significant decrease in fluid intake and in body weight gain compared to the controls. In liver supernatants obtained from all tested rats a statistically significant increase in MDA concentration was demonstrated in spontaneous LPO in comparison with the control rats. Moreover, in rats intoxicated with vanadium alone a statistically significant increase in liver MDA level was observed in the presence of 100microM NaVO(3). Instead, in supernatants of liver received from rats treated with chromium alone, a statistically significant increase in MDA concentration in comparison with the controls was found in the presence of 400microM NaVO(3). In kidney supernatants obtained from rats treated with chromium alone, a statistically significant increase in lipid peroxidation was shown in the presence of 30microM FeSO(4) and 400microM NaVO(3). These results show that the tested doses of vanadium(V) and chromium(III) ingested by rats with their drinking water caused significant alterations in internal organs, especially in liver. Under the conditions of our experiment, Cr(III) did not demonstrate antioxidant action, it rather had an oxidant effect.     

Acute Toxicity of Amorphous Silica Nanoparticles in Intravenously Exposed ICR Mice

This study aimed to evaluate the acute toxicity of intravenously administrated amorphous silica nanoparticles (SNPs) in mice. The lethal dose, 50 (LD₅₀), of intravenously administrated SNPs was calculated in mice using Dixon''s up-and-down method (262.45±33.78 mg/kg). The acute toxicity was evaluated at 14 d after intravenous injection of SNPs at 29.5, 103.5 and 177.5 mg/kg in mice. A silicon content analysis using ICP-OES found that SNPs mainly distributed in the resident macrophages of the liver (10.24%ID/g), spleen (34.78%ID/g) and lung (1.96%ID/g). TEM imaging showed only a small amount in the hepatocytes of the liver and in the capillary endothelial cells of the lung and kidney. The levels of serum LDH, AST and ALT were all elevated in the SNP treated groups. A histological examination showed lymphocytic infiltration, granuloma formation, and hydropic degeneration in liver hepatocytes; megakaryocyte hyperplasia in the spleen; and pneumonemia and pulmonary interstitial thickening in the lung of the SNP treated groups. A CD68 immunohistochemistry stain indicated SNPs induced macrophage proliferation in the liver and spleen. The results suggest injuries induced by the SNPs in the liver, spleen and lungs. Mononuclear phagocytic cells played an important role in the injury process.     

Aluminium accumulates on inactive bone surfaces after parathyroidectomy in uremic rats

In recent studies on bone biopsies of long-term hemodialyzed patients, parathyroidectomy (PTx) has been shown to represent a risk factor for subsequent accumulation of aluminium (Al) in the bone. Therefore, the influence of late PTx on Al metabolism in uremic rats previously given 11 mg Al intraperitoneally during a period of four weeks was studied. Al content was determined in the blood, liver, bone and feces 7 and 14 days after PTx. During PTx, each animal also received 2 intramuscular implants of partially demineralized bone matrix cylinders, which served as inactive bone surfaces. In PTx animals, the Al content in the liver, spleen and kidney progressively decreased, while its blood levels increased in spite of the fact that the treatment was stopped. Bone values remained unchanged but Al markedly accumulated on inactive mineralized surfaces of implanted cylinders. Significant amounts of Al in fecal masses could indicate its biliary excretion. The results were influenced neither by changes in 1,25-(OH)2D3 or serum calcium values, nor by different degrees of renal failure after PTx. It is suggested that accumulation of Al in the bone after PTx, as found in dialyzed patients, constitutes a passive event triggered by inactive bone tissue.     

Tissue-dependent preventive effect of metallothionein against DNA damage in dyslipidemic mice under repeated stresses of fasting or restraint

AimsTo investigate the effect of repeated stress on DNA damage in seven organs of dyslipidemic mice, and the preventive role of metallothionein (MT).Main methodsFemale adult 129/Sv wild-type and MT-null mice fed high-fat diet (HFD) were repeatedly subjected to mild stress of fasting or restraint in weeks 2 to 4 of 4-week study period. Serum cholesterol level, DNA damage in the liver, pancreas, spleen, bone marrow, kidney, lung and gastric mucosa, and other parameters were determined.Key findingsBody weights were increased in both types of mice fed HFD compared to those fed standard diet (STD), and further increased by 12 h-fasting, while they were markedly decreased by 1–3 h-restraint. Fasting accelerated accumulation of fat in the liver, and increase in serum cholesterol of both types of mice fed HFD. Feeding of HFD increased DNA damage in the pancreas, spleen and bone marrow of both types of mice, compared with those fed STD. In the wild-type mice fed HFD, 24 h-fasting increased DNA damage in the liver and spleen, while restraint increased the damage in the liver, pancreas, spleen and bone marrow. DNA damage in the cells of organs was markedly increased in the MT-null mice. Specifically, damage in the liver, pancreas, spleen and bone marrow was greatly increased with the intensity of stress increased, and the damage was much greater in the restraint mice than in the fasting mice.SignificanceMT plays a tissue-dependent preventive role against DNA damage in various murine organs induced by repeated stress.     

Protective effects of azelaic acid against high-fat diet-induced oxidative stress in liver, kidney and heart of C57BL/6J mice

Excess fat intake induces hyperinsulinaemia, increases nutrient uptake and lipid accumulation, amplifies ROS generation, establishes oxidative stress and morphological changes leading to tissue injury in the liver, kidney and heart of high-fat diet (HFD)-fed mice. The effect of azelaic acid (AzA), a C9 α,ω-dicarboxylic acid, against HFD-induced oxidative stress was investigated by assaying the activities and levels of antioxidants and oxidative stress markers in the liver, kidney and heart of C57BL/6J mice. Mice were segregated into two groups, one fed standard diet (NC) and the other fed high-fat diet (HFD) for 15 weeks. HFD-fed mice were subjected to intragastric administration of AzA (80 mg/kg BW)/RSG (10 mg/kg BW) during 11-15 weeks. Glucose, insulin, triglycerides, hepatic and nephritic markers were analysed in the plasma and the activity of enzymatic, non-enzymatic antioxidants and lipid peroxidation markers were examined in the plasma/erythrocytes, liver, kidney and heart of normal and experimental mice. We inferred significant decrease in enzymatic and non-enzymatic antioxidants along with significant increase in glucose, insulin, hepatic and nephritic markers, triglycerides and lipid peroxidation markers in HFD-fed mice. Administration of AzA could positively restore the levels of plasma glucose, insulin, triglycerides, hepatic and nephritic markers to near normal. AzA increased the levels of enzymatic and nonenzymatic antioxidants with significant reduction in the levels of lipid peroxidation markers. Histopathological examination of liver, kidney and heart substantiated these results. Hence, we put forward that AzA could counteract the potential injurious effects of HFD-induced oxidative stress in C57BL/6J mice.     

Distribution of cadmium in selected organs of mice: effects of cadmium on organ contents of retinoids and beta-carotene

Cadmium was administered to 32 adult ICR mice i.p. in two single doses (0.25 and 0.5 mg CdCl2, per kg of b.w.). After 48 hours concentrations of cadmium in kidneys, liver, spleen, muscle (m. quadriceps femoris), ovaries and testes and the concentration of retinyl palmitate, retinol and beta-carotene in kidney, liver and testes were determined. Significantly higher cadmium concentration was found in liver, kidney and ovary in both experimental groups in comparison with the control group (p<0.001). In muscle, spleen and testis the cadmium level was higher, however not significantly. No significant differences in the concentration of retinyl palmitate, retinol and alpha-carotene in liver were found. Concentration of alpha-carotene in kidney and testis was significantly decreased in both groups administered with cadmium (p<0.001). Concentration of retinyl palmitate was significantly lower in testis in the group with higher cadmium level (p<0.001) and the concentration of retinol significantly decreased in kidney and testis of mice after an administration of 0.5 mg CdCl2/kg b.w.     

乳酸菌源有机硒对肝损伤小鼠脾脏脂质过氧化和NK细胞活性的保护效应研究

本文通过研究乳酸菌源有机硒干预CCl_4致肝损伤小鼠脾脏NK细胞活性和脂质过氧化反应的变化,探讨该有机硒在抗损伤保护过程中的效应及其机制。分别选用60只健康成年小鼠,雌雄对半,随机分成对照组(C组),有机硒组(Se组),CCl_4组、CCl_4-有机硒保护组(CCl_4-Se组),每组15只。通过腹腔注射CCl_4诱发肝损伤后,分别在第2、4周检测脾脏NK细胞活性及其组织匀浆GSH-Px、CAT、SOD活性和MDA含量变化、结果显示,在整个实验期内,C组、Se组和CCl_4-Se组脾组织匀浆GSH—Px、CAT和SOD活性均高于或明显高于CCl_4组,Se和CCl_4-Se组与C组比较除SOD活性在第4周有明显升高外均差异不显著;CCl_4组小鼠脾脏MDA含量均显著高于C组、Se组和CCl_4-Se组,而CCl_4-Se组与C组接近,Se组较CCl_4-Se组和C组低;Se组NK细胞活性最高,第4周明显高于C组,CCl_4组最低且低于或明显低于CCl_4-Se、Se和C组,CCl_4-Se组与C组无明显差异。结果提示,乳酸菌源有机硒能够提高正常机体抗氧化能力,在干预肝损伤过程中,可以通过改善和提高脾组织抗氧化酶活性及NK细胞活性发挥积极有效的作用。     

The fate of Cd,Cu, Ca,Zn, and Fe in rat during the recovery period following cessation of repeated exposure to Cd

Cadmium was administered subcutaneously to male Wistar rats, 0.1 mL/rat in 0.9% saline 3 times a wk for 4 wk at 3 mg Cd/kg. Saline was administered to control animals in an equivalent manner, without Cd. After the end of the dosing period, the distribution and excretion of Cd, Cu, Ca, Zn, and Fe were observed in some organs and excreta for 35 d (1, 7, 14, 21, 28, and 35 d). Cadmium dosing caused significant disturbances in the metabolism of Zn, Cu, Fe, and Ca, especially during the recovery period. Growth in Cd-dosed animals did not accelerate, even after 5 wk of recovery. There was evidence of mobilization of some elements among organs. Accumulation of Cd occurred in liver, kidney, and spleen during dosing, and during the recovery period it was retained in kidney and testes (for 2 wk) and cleared steadily in liver and RBC (for 5 wk), but increased in spleen (first 3 wk). The pattern of Cd excretion was closely associated with the binding of Cd with metallothioneins in kidney and liver for the first 21 and 7 d, respectively. This was associated with the excretion of Cd-metallothioneins (Cd-MT) in urine from d 1 to 21 during recovery. Cadmium caused higher Ca accumulations in testes and liver, which were probably associated with the lesions observed in these organs. Significant increases of Cu (in kidney d 7) and Fe (in liver) were observed during recovery. Furthermore, significant reductions of Cu and Fe were found in plasma, spleen, and RBC (after 5 wk) and kidney, spleen, and testes (on d 7), and blood (after 5 wk).     

不同周龄Balb/c小鼠脏器质量及其变化趋势分析

目的:测定不同周龄Balb/c小鼠主要脏器质量、脏器系数,并进行比较。方法:取120只3周龄、5周龄、7周龄的Balb/c小鼠,雌雄各半,精确测量小鼠体重和主要脏器质量,计算脏器系数。结果:①雌性与雄性Balb/c小鼠脏器质量相比较:3周龄时肝、脾有显著差异(P0.05);5周龄时肝有非常显著差异(P0.01),脾、肺有显著差异(P0.05);7周龄时肝、肺及双肾有非常显著差异(P0.01),心、脾有显著差异(P0.05)。②雌性与雄性Balb/c小鼠脏器系数相比较:3周龄时肝、脾有显著差异(P0.05);5周龄时肝、脾有非常显著差异(P0.01),膀胱有显著差异(P0.05);7周龄时肺、双肾有非常显著差异(P0.01),脾、膀胱有显著差异(P0.05)。结论:随着周龄的增长,Balb/c雌、雄性小鼠之间,存在差异的脏器也在增多。     

Chromium attenuates high-fat diet-induced nonalcoholic fatty liver disease in KK/HlJ mice

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with insulin resistance, oxidative stress, and inflammation. Evidence indicates that chromium has a role in the regulation of glucose and lipid metabolism and may improve insulin sensitivity. In this study, we report that chromium supplementation has a beneficial effect against NAFLD. We found that KK/HlJ mice developed obesity and progressed to NAFLD after feeding with high-fat diet for 8 weeks. High-fat-fed KK/HlJ mice showed hepatocyte injury and hepatic triglyceride accumulation, which was accompanied by insulin resistance, oxidative stress, and inflammation. Chromium supplementation prevented progression of NAFLD and the beneficial effects were accompanied by reduction of hepatic triglyceride accumulation, elevation of hepatic lipid catabolic enzyme, improvement of glucose and lipid metabolism, suppression of inflammation as well as resolution of oxidative stress, probably through enhancement of insulin signaling. Our findings suggest that chromium could serve as a hepatoprotective agent against NAFLD.     

Effects of taurine on oxidative stress parameters and chromium levels altered by acute hexavalent chromium exposure in Mice Kidney tissue

The kidney has been regarded as a critical organ of toxicity induced by acute exposure to hexavalent chromium [Cr(VI)] compounds. Reactive intermediates and free radicals generated during reduction process might be responsible for Cr(VI) toxicity. In this study, the effects of pretreatment or posttreatment of taurine on Cr(VI)-induced oxidative stress and chromium accumulation in kidney tissue of Swiss albino mice were investigated. Single intraperitoneal (ip) potassium dichromate treatment (20 mgCr/kg), as Cr(VI) compound, significantly elevated the level of lipid peroxidation as compared with the control group (p<0.05). This was accompanied by significant decreases in nonprotein sulfhydryls (NPSH) level, superoxide dismutase (SOD), and catalase (CAT) enzyme activities as well as a significant chromium accumulation (p<0.05). Taurine administration (1 g/kg, ip) before or after Cr(VI) exposure resulted in reduction of lipid peroxidation levels and improvement in SOD enzyme activity (p<0.05). On the other hand, administration of the antioxidant before Cr(VI) exposure restored the NPSH level and CAT enzyme activity and also reduced tissue chromium levels (p<0.05), whereas postreatment had only slight effects on these parameters. In view of the results, taurine seems to exert some beneficial effects against Cr(VI)-induced oxidative stress and chromium accumulation in mice kidney tissue.     

Tritium distribution in newborn mice after providing mother mice with drinking water containing tritiated thymidine

Throughout gestation pregnant mice received drinking water which contained [methyl-3H]thymidine (18.5 kBq/ml). The newborn mice were divided into two groups. One group was nursed by their own mothers, which were further supplied with tritiated thymidine until 4 weeks after delivery (Experiment I). The other group was nursed by "nonradioactive mothers" which were given no tritiated thymidine (Experiment II). Tritium incorporation into the small molecular components of the acid-soluble fraction, lipid, RNA, DNA, and protein was analyzed for the newborn mice at various ages. In Experiment II, total radioactivity per gram tissue decreased initially after birth with a half life of 2.5-2.9 days in spleen, liver, intestine, stomach, thymus, lung, kidney, heart, and brain. At about 2 weeks after birth, a slower component of tritium elimination due mainly to the DNA-bound tritium appeared. Specific activity of DNA at birth was organ specific, highest in heart and lowest in thymus. Cumulative absorbed dose in various organs was estimated for the first 4 weeks after birth based upon an assumption that total and DNA-bound tritium are uniformly distributed. The result showed that organ specificity of dose accumulation is obvious for DNA-bound tritium, highest in spleen (1.15 mGy) and lowest in brain (0.13 mGy). It was also shown that the tritium supply from mother's milk is of minor importance for dose accumulation of DNA-bound tritium in the cell nuclei of organs of suckling mice.     

人脐带间充质干细胞重复静脉注射动物毒性试验

摘要 目的：评价多次尾静脉注射脐带间充质干细胞（hUC-MSCs）对小鼠的体内毒性作用。方法：48只健康ICR小鼠,按性别和体重随机分为4组（即对照组、低剂量组、中剂量组和高剂量组）。小鼠通过微静脉注射不同剂量hUC-MSCs悬浮液,间隔3天给药1次,共给药4次。记录小鼠摄食量、体重、体温,给药结束后恢复两周后牺牲动物作大体解剖,检查各个器官器质性病变;利用流式细胞仪分别检测CD3、CD4、CD8阳性细胞亚群数量;ELISA试剂盒检测血清IgM、IgG、C3、C4指标;对肺脏、脾脏、肾脏行组织病理学检查。结果：实验组与对照组相比较,注射不同剂量干细胞后一般观察、体重、体温、摄食量、IgM以及C3在给药期和恢复期均未发生显著变化。在恢复期,注射中、高剂量hUC-MSCs组血清IgG和C4水平略有降低,但未达到显著水平P<0.05;CD4阳性T细胞集群数量以及CD4/CD8系数在hUC-MSCs中、高剂量组显著上升（P<0.05）。大体剖检,除脾脏相比溶媒对照组略显增大外其它各器官均未发现肉眼可见明显异常;称重后发现hUC-MSCs高剂量组脾重量与溶媒对照组相比显著升高（P<0.05）。脾脏、肺脏、肾脏病理学检测未见明显异常。结论：健康ICR小鼠尾静脉注射临床剂量hUC-MSCs（1×10⁶ cells/kg）可能调动动物免疫反应,此外,未观察到hUC-MSCs对小鼠有明显毒副作用。