Chronic effects of cyanobacterial toxins on Daphnia magna and their offspring

The zooplankton grazer Daphnia magna endures living in water bodies up to moderate densities of cyanobacteria, such as Microcystis spp., known for producing toxic secondary metabolites. Although daphnids are affected via decreased food filtering, inhibition of digestive proteases and lethality, development of tolerance against cyanobacterial toxins has also been observed. Aim of our study was to investigate in detail chronic effects of cyanobacterial toxins, with emphasis on microcystin, on D. magna. The animals were exposed chronically for two generations to either microcystin-LR in 5 or 50 μg L⁻¹, or to cyanobacterial crude extract containing the same amount of total microcystin, starting at neonate stadium. Survival, growth, maturation and fecundity were observed for the first generation during two months. In the offspring survival, maturation, and growth were followed for the first week.Low concentration of microcystin-LR slightly affected the growth and reproduction of parent daphnids. Survivorship decreased during chronic exposure with increasing microcystin concentration. Age to maturity of the offspring increased and their survival decreased after parent generation was exposed to the toxin, even if the offspring were raised in control medium. Besides, cessation of the eggs/embryos was observed and malformation of neonates caused by cyanobacterial toxins was firstly recorded.     

Quantitative structure-activity relationships and toxicity studies of mixtures of chemicals with anaesthetic potency: Acute lethal and sublethal toxicity to Daphnia magna

In this study quantitative structure-activity relationships (QSARs) were calculated between hydrophobicity of a group of organic chemicals with anaesthetic potency and toxicity (immobilization, mortality and inhibition of reproduction) to Daphnia magna. Differences in slopes of the high quality QSARs might be explained in terms of possible different sites of action for the three criteria of effect.The combined effects of mixtures of 5–50 chemicals on immobilization and mortality did not deviate from additivity, while the effect on reproduction deviated somewhat from it.     

Effects of the artificial sweetener sucralose on Daphnia magna and Americamysis bahia survival, growth and reproduction

The artificial sweetener sucralose has been detected in municipal wastewater effluent and surface waters at concentrations ranging from ng/L to low μg/L. Few chronic ecotoxicological data are available in the peer reviewed literature with respect to sucralose. To address this data gap, 21 d Daphnia magna and 28 d Americamysis bahia (mysid shrimp) studies were conducted to assess the effects of sucralose on the survival, growth and reproduction of these organisms. Concentrations ?1800 mg/L resulted in no statistically significant reduction in D. magna survival or reproduction. Survival, growth and reproduction of mysid shrimp were unaffected by ?93 mg/L sucralose. The no observable effect concentration (NOEC) and lowest observable effect concentration (LOEC) for the D. magna study were 1800 and >1800 mg/L, respectively. The NOEC and LOEC for the mysid study were 93 and >93 mg/L, respectively. Collectively, these data suggest that the concentrations of sucralose detected in the environment are well below those required to elicit chronic effects in freshwater or marine invertebrates.     

The critical importance of defined media conditions in Daphnia magna nanotoxicity studies

Due to the widespread use of silver nanoparticles (AgNPs), the likelihood of them entering the environment has increased and they are known to be potentially toxic. Currently, there is little information on the dynamic changes of AgNPs in ecotoxicity exposure media and how this may affect toxicity. Here, the colloidal stability of three different sizes of citrate-stabilized AgNPs was assessed in standard strength OECD ISO exposure media, and in 2-fold (media2) and 10-fold (media10) dilutions by transmission electron microscopy (TEM) and atomic force microscopy (AFM) and these characteristics were related to their toxicity towards Daphnia magna. Aggregation in undiluted media (media1) was rapid, and after diluting the medium by a factor of 2 or 10, aggregation was reduced, with minimal aggregation over 24 h occurring in media10. Acute toxicity measurements were performed using 7 nm diameter particles in media1 and media10. In media10 the EC₅₀ of the 7 nm particles for D. magna neonates was calculated to be 7.46 μg L⁻¹ with upper and lower 95% confidence intervals of 6.84 μg L⁻¹ and 8.13 μg L⁻¹ respectively. For media1, an EC₅₀ could not be calculated, the lowest observed adverse effect concentration (LOAEC) of 11.25 μg L⁻¹ indicating a significant reduction in toxicity compared to that in media10. The data suggest the increased dispersion of nanoparticles leads to enhanced toxicity, emphasising the importance of appropriate media composition to fully assess nanoparticle toxicity in aquatic ecotoxicity tests.     

Sublethal effects of treated liquid effluent from a petroleum refinery. V. Reproduction of Daphnia pulex and overall evaluation

The 48-h LC₅₀ of treated refinery effluent for 2-day-old Daphnia pulex was 76% effluent. The 14-day LC₅₀ was 6.4% effluent and this was a threshold value for mortality. For reproductive failure, the 14-day EC₅₀ was 3.1% effluent, and the EC₅ of 0.52% effluent was considered to approximate the threshold of sublethal effect.Daphnia reproduction was the most sensitive response in a series of studies that included fish growth, reproduction, locomotion, and respiration. Results are considered representative for a well-treated effluent from a petroleum refinery. The 48-h lethal test with D. pulex would be a useful tool for monitoring or assessing such effluents, since it is simple, small-scale, quick, and about 2.6 times as sensitive as a lethal test with trout.     

The effects of dietary nickel exposure on growth and reproduction of Daphnia magna

Although there is growing evidence that dietborne metals can be toxic to various aquatic species, there is still insufficient knowledge to integrate this information in environmental risk assessment procedures. In this study, we investigated the effects of a 21-day exposure of Daphnia magna to a control diet (i.e. the green alga Pseudokirchneriella subcapitata containing <4.0 μg Ni/g dry wt) and five diets with elevated Ni concentrations (i.e. the same alga contaminated with Ni burdens between 33.7 and 837 μg Ni/g dry wt). A significant accumulation of dietborne Ni in D. magna, i.e. between 49.6 and 72.5 μg Ni/g dry wt, was observed when they were fed with diets containing between 85.6 and 837 μg Ni/g dry wt. This was paralleled by a significant reduction of reproduction (by 33.1%), measured as the total number of juvenile offspring per female and growth (by 9.1%), measured as the carapax length of 21-day-old females. Life-history analysis showed that the time to first brood of Ni exposed organisms was between 7.8 and 8.2 days, and occurred 0.7–1.1 days earlier than for the control organisms (time to first brood = 8.9 days). The number of offspring in the first brood was significantly reduced (by 21–33% compared to the control) in all dietary treatments. Longer exposure (≥8.9 days, i.e. from the second brood onwards) led to a reduction of brood size only when given diets containing 85.6 and 837 μg Ni/g dry wt. The results suggest that a variety of mechanisms may be involved in the effects of dietary Ni exposure, including altered resource allocation or targeted reproductive inhibition. While Ni exposure clearly altered the quality of the diet (measured as essential ω3 polyunsaturated fatty acid content and C:P ratio), we found no conclusive evidence that these diet quality shifts could have affected growth or total reproductive output. More research is required to fully understand the mechanisms of Ni toxicity associated with the dietary exposure route.     

Risk assessment of pesticides and heavy metals contaminants in vegetables: A novel bioassay method using Daphnia magna Straus

Cucumber and potato samples of known levels of pesticides and heavy metal residues, as respectively measured by gas chromatography and atomic absorption, were subjected to a bioassay method using Daphnia magna in order to assess the potential of the toxic hazard of their contaminants. Based on the estimated lethal time for 50% mortality (LT50) in daphnids, we suggested a classification to categorize toxic hazards in six definite ratings. Either samples of cucumbers (from conventional, greenhouse and organic farming) or potatoes (from conventional and organic farming) were evaluated for toxic hazard of the mixtures of pesticide residues and heavy metals, as well as mixtures of both. Accordingly, a 53.7% of cucumber samples were ranked as “Highly Toxic: HT”; a 18.5% “Moderately Toxic: MT); a 9.3% “Slightly Toxic: ST”; and a 18.5% “Practically Non-Toxic: NT”. For potato samples, the ranking pattern to different classes was: Extremely Toxic: ET (LT50 = <1 h) for 11.1%; Very Toxic: VT (LT50 = 1–<3 h) for 50.0%; HT (LT50 = 3–<12 h) for 13.9%; MT (LT50 = 12–<24 h) for 11.1%; ST (LT50 = 24–48 h) for 0.0%; and NT (LT50 = > 48 h) for 13.9% of the samples bioassayed.     

Standard curves for nuvacron,malathion, sevin,DDT and kelthane tested against the mosquito Culex pipiens L. and the microcrustacean Daphnia magna Straus

The fourth instar larvae of Culex pipiens L. and adults of microcrustacean Daphnia magna Straus were reared under standarized conditions and used as bioassay test organisms for the preparation of the standard log concentration-probit (lc-p) regression lines for each of the following pesticides: nuvacron, malathion, sevin, DDT and kelthane.When the above pesticides were tested against the larvae of C. pipiens, the LC₅₀ values (in ppm) ranged as follows: nuvacron 0.0014–0.0019, malathion 0.0027–0.0043, sevin 0.059–0.095, DDT 0.233–0.525, kelthane 0.17–0.24 and a mixture of malathion, DDT and kelthane (3 : 10 : 5) 0.1805–0.2451, based on 24-h readings. The corresponding LC₅₀ values (in ppm) for D. magna were 0.00018–0.00032, 0.000074–0.00013, 0.00063–0.00069, 0.0061–0.0064, 0.071–0.090 and 0.022–0.028 for the aforementioned pestcides. D. magna proved to be more sensitive to all tested pesticides than C. pipiens larvae: it succumbed to concentrations ranging from 0.000032 to 0.004 ppm of nuvacron, from 0.000032 to 0.0016 ppm of malathion, from 0.000032 to 0.02 ppm of sevin, from 0.0008 to 0.1 ppm of DDT, from 0.03 to 0.3 ppm of kelthane and from 0.007 to 0.075 ppm of the mixture. C. pipiens larvae were affected by concentrations ranging from 0.0005 to 0.008 ppm of nuvacron, from 0.0005 to 0.04 ppm of malathion, from 0.008 to 1.0 ppm of sevin, from 0.05 to 2.5 ppm of DDT, from 0.06 to 0.5 ppm of kelthane and from 0.07 to 0.75 ppm of the mixture.     

Methylmercury effects on reproduction and offspring size at birth

This article describes a study of the toxic, reproductive, and developmental effects of chronic methylmercury (MeHg) exposure in Macaca fascicularis monkeys. Adult and infant monkeys were studied using procedures to assess maternal and newborn blood Hg concentrations, menstrual cyclicity, conception rate, reproductive outcome, maternal toxicity, and offspring size at birth. Maternal intakes of 0, 50, 70, or 90 μg/kg/d MeHg hydroxide were studied. Maternal blood Hg concentrations reached equilibrium by 10 weeks of exposure. The half-life of blood Hg for adult females ranged from 15 to 40 days ( ) and did not vary with dose. Maternal MeHg exposure did not affect the length of the menstrual cycle or the conception rate. Maternal MeHg exposure did significantly reduce the number of viable deliveries at blood Hg concentrations above 1.5 ppm. Maternal blood Hg concentrations at delivery were significantly lower than newborn concentrations. No effect of maternal MeHg exposure on offspring size at birth was observed. Maternal toxicity was related to blood Hg concentrations above 2.0 ppm following approximately one year of exposure. Results indicate that MeHg exposure can affect reproductive outcome at levels that do not overt toxicity.     

八正合剂抗感染作用及其作用机理探讨

目的探讨八正合剂治疗泌尿系统感染性疾病的药理学作用及机理。方法将大肠杆菌注入小鼠膀胱后观察药物对细菌上行感染肾脏的抑制作用;同时检测其对小鼠免疫功能的影响。结果八正合剂灌胃给药可显著降低小鼠大肠杆菌上行感染肾脏的带菌剖面百分率[ED50为(11.01±1.63)g·kg-1,95%可信限为9.50~12.76g·kg-1],显著提高小鼠巨噬细胞吞噬率和吞噬指数,对体液免疫和细胞免疫影响不大。结论八正合剂治疗泌尿系统感染性疾病的作用机制主要与其增强巨噬细胞吞噬功能、清除尿路细菌有关。     

百部荆芥合剂药效学实验研究

目的:研究不同浓度的百部荆芥合剂在止咳、祛痰及平喘方面的药理学作用。方法:采用小鼠浓氨水法、酚红法及豚鼠喷雾法观察百部荆芥合剂在止咳、祛痰及平喘方面的作用同时,分别选用磷酸可待因和氨茶碱作为阳性药物对照比较。结果:百部荆芥合剂对小鼠浓氨水法诱发的咳嗽具有明显的抑制作用,可延长咳嗽的潜伏期(P<0.01),使咳嗽次数减少、排痰量增多,对乙酰胆碱、组织胺混合喷雾造成的豚鼠哮喘具有明显的对抗作用(P<0.01)。结论:百部荆芥合剂具有较强的止咳、祛痰及平喘作用。     

鱼腥草桔梗合剂止咳、祛痰及平喘作用研究

目的:观察研究不同浓度的鱼腥草、甘草,止咳、祛痰及平喘的药理作用。方法:采用小鼠“浓氨水法”、“酚红法”及豚鼠“喷雾法”观察合剂在止咳、祛痰、平喘等方面的作用,同时分别选用磷酸可待因和氨茶碱作为阳性药物对照比较。结果:鱼腥桔梗合剂对小鼠“浓氨水法”诱发的咳嗽具有明显的抑制作用,可延长咳嗽潜伏期(P<0.01),使咳嗽次数减少,使排痰量增加,对乙酰胆碱、组织胺混合液喷雾造成的豚鼠哮喘具有较明显的对抗作用(P<0.05)。结论:鱼腥草桔梗合剂具有较强的止咳,祛痰及平喘作用。     

水蛭抗纤维化临床疗效观察

目的观察中药水蛭对肝硬化的治疗作用。方法选择2006年8月-2007年8月在院感染科住院及门诊就诊的肝郁脾虚型肝硬化患者30例,随机分成2组,每组各15例,分别在药物中加用水蛭和去除水蛭。干预治疗3个月。观察症状前后变化,症状分级量化评分标准：按无、轻、中、重分4个等级记分,分别记“-”（无）、“＋”（轻）、“＋＋”（中）、“＋＋＋”（重）;每个“＋”记1分,“-”记0分。具体评价内容：胁肋疼痛、脘闷腹胀、倦怠乏力、大便稀溏。治疗前后采用放免法检测血清Ⅲ型前胶原（PCⅢ）、透明质酸（HA）、层粘连蛋白（LN）、Ⅳ型胶原（IV—C）水平。结果2组治疗后肝硬化患者症状均有改善,水蛭治疗组胁肋疼痛症状改善更明显。治疗前后HA、LN指标有明显差异,水蛭组治疗后血清PCⅢ浓度明显降低。结论在抗肝硬化中药复方中加用水蛭,有助于提高中药复方合荆抗肝纤维化治疗效果。     

Acute effects of a low‐dose atropine/scopolamine mixture as a food contaminant in human volunteers

To verify the assumptions in our previous risk assessment of an atropine/scopolamine mixture in buckwheat flour, we performed a randomized, double‐blind, placebo‐controlled cross‐over study in 20 healthy, adult volunteers. The volunteers ingested a traditional Slovenian buckwheat meal, made of boiled buckwheat flour to which alkaloids were added. In addition to the placebo they ingested 0.12/0.10, 0.37/0.29, 1.22/0.95, 3.58/2.81 and 12.10/9.50 µg kg^–1 body mass (BM) of the atropine/scopolamine mixture. The changes in body temperature, heart rate, salivary and sweat secretion, pupil size, near‐point vision and subjective symptoms were recorded regularly for 4 h after the ingestion. Decreased salivary and sweat secretion, increased heart rate and pupil size and reduced near‐point vision accompanied by characteristic subjective symptoms were observed at 12.10/9.50 µg kg^–1 BM. At doses of 0.37/0.29 and 1.22/0.95 µg kg^–1 BM, a significant decrease in the heart rate was noted, which we consider to be a critical effect of a low‐dose exposure to the atropine/scopolamine mixture. Although this did not have any clinical relevance in our subjects, it may have serious implications if it occurred in people with pre‐existent cardiac conditions or those on medications that may cause bradycardia. No significant changes in the observed end points were noted at 0.12/0.10 µg kg^–1 BM. We estimate that the NOAEL (No Observed Adverse Effect Level) for the atropine/scopolamine mixture lies between the lower two administered doses. Applying the uncertainty factor of 10, we propose a new provisional Acute Reference Doses (ARfDs) of the mixture, i.e. 0.01 µg kg^–1 BM for each alkaloid, and a further refinement using higher‐tier approaches. Copyright © 2012 John Wiley & Sons, Ltd.     

In vitro to in vivo concordance of a high throughput assay of bone marrow toxicity across a diverse set of drug candidates

The development of predictive toxicology assays is necessary to optimize the drug candidate selection process. The colony forming assay (CFA) is used routinely to assess bone marrow toxicity and represents a viable tool for the discovery toxicologist, but the assay is not widely accepted as a standard screening tool due to technical challenges. A higher throughput and standardized version of the assay recently was developed such that the proliferative capacity of a cell lineage is measured indirectly via ATP levels, replacing the cumbersome identification and enumeration of specific colonies. In this study, a high-throughput assay of bone marrow toxicity prediction using the granulocyte, erythrocyte, monocyte, and macrophage (GEMM) progenitor cell lineage was evaluated using a training set of 56 structurally diverse compounds with known in vivo bone marrow effects. In general, compounds identified as toxic in vivo had lower IC₅₀ values, whereas those identified as non-toxic had higher IC₅₀ values. Concordance (i.e., predictive accuracy) to in vivo bone marrow toxicity results was 82% when an in vitro toxicity threshold of 20 μM was used. Additional experiments in other hematopoietic lineages were conducted to determine if predictivity of several false positive and negative compounds in the GEMM lineage could be improved; however an increase in sensitivity or specificity was not observed. The high-throughput GEMM assay has good concordance to in vivo bone marrow toxicity results and, with the high-throughput and standardized format, can be incorporated readily into the pharmaceutical toxicological screening paradigm, aiding in the early identification of compounds that eventually may fail due to bone marrow toxicity.     

Dermal toxicity,eye and dermal irritation and skin sensitization evaluation of a new formulation of Bacillus thuringiensis var israelensis SH-14

Bacillus thuringiensis (Bt) is the best known and most widely used of all pesticidal microbes. The aim of this study was to assess the toxicity of a new formulation of Bacillus thuringiensis var israelensis SH-14 in rats through acute dermal toxicity, dermal and eye irritation experiments. The acute dermal toxicity and dermal and eye irritation studies were performed using rabbits according to the United States Environmental Protection Agency guidelines 885.3100, 870.2500 and 870.2500, respectively. The skin sensitization study was carried out in accordance to the EPA OPPTS 870.2600 using guinea pigs. There was no mortality and no evidence of treatment-related toxicity in acute dermal toxicity test. No dermal responses, including erythema/eschar or edema, were found in rabbits treated with the new formulation of Bti SH-14. Minimum response was observed after eye application of test substance. No skin sensitization reactions were observed after the challenge with the new formulation of Bti SH-14 in the Bti SH-14-treated guinea pigs. In summary, the present study demonstrated that the new formulation of Bti SH-14 is not acutely toxic via dermal route, has low eye irritation and would not cause dermal irritation or hypersensitivity to tested animals.     

Effects of an ethanol-gasoline mixture: results of a 4-week inhalation study in rats

The inhalation toxicity of an ethanol-gasoline mixture was investigated in rats. Groups of 15 male and 15 female rats were exposed by inhalation to 6130 ppm ethanol, 500 ppm gasoline or a mixture of 85% ethanol and 15% gasoline (by volume, 6130 ppm ethanol and 500 ppm gasoline), 6 h a day, 5 days per week for 4 weeks. Control rats of both genders received HEPA/charcoal-filtered room air. Ten males and ten females from each group were killed after 4 weeks of treatment and the remaining rats were exposed to filtered room air for an additional 4 weeks to determine the reversibility of toxic injuries. Female rats treated with the mixture showed growth suppression, which was reversed after 4 weeks of recovery. Increased kidney weight and elevated liver microsomal ethoxyresorufin-O-deethylase (EROD) activity, urinary ascorbic acid, hippuric acid and blood lymphocytes were observed and most of the effects were associated with gasoline exposure. Combined exposure to ethanol and gasoline appeared to exert an additive effect on growth suppression. Inflammation of the upper respiratory tract was observed only in the ethanol-gasoline mixture groups, and exposure to either ethanol and gasoline had no effect on the organ, suggesting that an irritating effect was produced when the two liquids were mixed. Morphology in the adrenal gland was characterized by vacuolation of the cortical area. Although histological changes were generally mild in male and female rats and were reversed after 4 weeks, the changes tended to be more severe in male rats. Brain biogenic amine levels were altered in ethanol- and gasoline-treated groups; their levels varied with respect to gender and brain region. Although no general interactions were observed in the brain neurotransmitters, gasoline appeared to suppress dopamine concentrations in the nucleus accumbens region co-exposed to ethanol. It was concluded that treatment with ethanol and gasoline, at the levels studied, produced mild, reversible biochemical hematological and histological effects, with some indications of interactions when they were co-administered.     

Toxicity of mixtures of zinc oxide and graphene oxide nanoparticles to aquatic organisms of different trophic level: particles outperform dissolved ions

Concomitant releases of various engineered nanoparticles (NPs) into the environment have resulted in concerns regarding their combined toxicity to aquatic organisms. It is however, still elusive to distinguish the contribution to toxicity of components in NP mixtures. In the present study, we quantitatively evaluated the relative contribution of NPs in their particulate form (NP_(particle)) and of dissolved ions released from NPs (NP_(ion)) to the combined toxicity of binary mixtures of ZnO NPs and graphene oxide nanoplatelets (GO NPs) to three aquatic organisms of different trophic levels, including an alga species (Scenedesmus obliquus), a cladoceran species (Daphnia magna), and a freshwater fish larva (Danio rerio). Our results revealed that the effects of ZnO NPs and GO NPs were additive to S. obliquus and D. magna but antagonistic to D. rerio. The relative contribution to toxicity (RCT) of the mixture components to S. obliquus decreased in the order of RCT_{GO NP(particle)} >?RCT_{ZnO NP(particle)}?>?RCT_{ZnO NP(ion)}, while the RCT of the mixture components to D. magna and D. rerio decreased in the order of RCT_{ZnO NP(particle)}?>?RCT_{GO NP(particle)}?>?RCT_{ZnO NP(ion)}. This finding also implies that the suspended particles rather than the dissolved Zn-ions dictated the combined toxicity of binary mixtures of ZnO NPs and GO NPs to the aquatic organisms of different trophic level. The alleviation of the contribution to toxicity of the ionic form of ZnO NPs was caused by the adsorption of the dissolved ions on GO NPs. Furthermore, the ZnO NP_(particle) and GO NP_(particle) displayed a different contribution to the observed mixture toxicity, dependent on the trophic level of the aquatic organisms tested. The difference of the contributions between the two particulate forms was mainly associated with differences in the intracellular accumulation of reactive oxygen species. Our findings highlight the important role of particles in the ecological impact of multi-nanomaterial systems.     

Joint toxicity of alkoxyethanol mixtures: Contribution of in silico applications

Exposure to chemicals occurs often as mixtures. Presented in this paper is information on alkoxyethanols and the impact they might have on human health in combination with some commonly found aliphatic and aromatic compounds. Our studies to evaluate the joint toxicity of these chemicals among themselves and in combination with other chemicals reveal a variety of possible outcomes depending on the exposure scenario. The interactions are predominantly based on metabolic pathways and are common among several solvents and organic compounds. Quantitative structure activity relationship (QSAR) analysis can be used with high confidence to identify chemicals that will interact to influence overall joint toxicity. Potential human exposure to a combination of alkoxyethanol, toluene and substituted benzenes may increase reproductive and developmental disease conditions. Inheritable gene alterations result in changes in the enzyme function in different subpopulations causing variations in quantity and/or quality of particular isoenzymes. These changes are responsible for differential metabolism of chemicals in species, genders, and life stages and are often the basis of a population’s susceptibility. Unique genotypes introduced as a function of migration can alter the genetic makeup of any given population. Hence special consideration should be given to susceptible populations while conducting chemical health risk assessments.     

大力新合剂对小鼠的耐缺氧及抗疲劳作用

目的:探讨大力新合剂对小鼠耐缺氧及抗疲劳作用。方法:取小鼠随机分成4组,对照组、大力新合剂高、中、低(2.30,1.15,0.575g.kg-1)剂量组。采用常压耐缺氧法记录小鼠缺氧存活时间;采用负重游泳法记录小鼠游泳存活时间,采用比色分析法测定小鼠游泳45min后血清乳酸及肝、肌糖原的含量。结果:大力新合剂能延长小鼠缺氧状态下的存活时间,延长小鼠负重游泳的存活时间,使小鼠游泳45min后血清乳酸含量明显减少,肝、肌糖原的含量明显增加。结论:大力新合剂具有耐缺氧和抗疲劳的作用,其机制可能与降低乳酸含量,增加肝、肌糖原含量有关。