Two-week oral toxicity study of 1,4-Dichloro-2-nitrobenzene in rats and mice

Subacute toxicity of 1,4-dichloro-2-nitrobenzene (DCNB) was examined by feeding F344 rats and BDF1 mice of both sexes a diet containing DCNB at 625, 1250, 2500, 5000 or 10,000 ppm (w/w) for 2 weeks. All DCNB-fed rats survived to the end of the 2-week administration period, but 2 male and 6 female mice fed 10,000 ppm died during this period. The subacute toxicity was characterized by lesions affecting the liver, kidney, testis and hematopoietic system. The liver was the most responsive to DCNB, as evidenced by a dose-related increase in relative liver weight in rats and mice and centrilobular hypertrophy of hepatocytes in mice. An alteration in liver-associated lipid metabolism was suggested from the concomitant increases in serum concentrations of total cholesterol and phospholipid. A lower confidence limit of the benchmark dose yielding the response with 10% extra risk (BMDL10) for the relative liver weight indicated that rats were more responsive to DCNB than mice. The kidney lesion was characterized by alpha2upsilon-globulin-accumulated hyaline droplets in the renal tubular epithelial cells only in male rats, as indicated by positive anti-alpha2upsilon-globulin immunohistochemical staining. Testicular and hematopoietic lesions appeared at higher dose levels than did the liver and kidney lesions.     

Carcinogenicity and chronic toxicity of 1,4-dichloro-2-nitrobenzene in rats and mice by two years feeding

Carcinogenicity and chronic toxicity of 1,4-dichloro-2-nitrobenzene (DCNB) were examined by feeding each group of 50 F344 rats and 50 BDF1 mice of both sexes a DCNB-containing diet at a concentration of 0 (control), 320, 800 or 2,000 ppm (w/w) for 2 yr. In rats, incidences of hepatocellular adenomas and carcinomas and their combined incidence were increased in the 2,000 ppm-fed males, together with increased incidence of basophilic cell foci in the 800 and 2,000 ppm-fed males. A dose-related increase in combined incidences of renal cell adenomas and carcinomas was noted. Incidence of Zymbal gland adenomas tended to increase in the 2,000 ppm-fed males. In mice, incidences of hepatocellular adenomas in the 800 and 2,000 ppm-fed females and hepatocellular carcinomas in the 2,000 ppm-fed males and in the 800 and 2,000 ppm-fed females were increased. Incidence of hepatoblastomas was increased in all DCNB-fed males and in the 2,000 ppm-fed females. Signs of chronic toxicity were characterized by centrilobular hypertrophy of hepatocytes with nuclear atypia in mice, increased relative liver weight in rats, a dose-related increase in incidences of chronic progressive nephropathy with advanced grades of severity in male rats, and decreased hemoglobin concentration and hematocrit accompanied by increased bone marrow hematopoiesis in female rats. Carcinogenic activity of DCNB was evaluated for the three different tumors, and sensitive signs of the chronic toxicity were dis-     

Thirteen-week inhalation toxicity of p-dichlorobenzene in mice and rats

Subchronic inhalation toxicity of p-dichlorobenzene (p-DCB) was examined by exposing BDF1 mice and F344 rats of both sexes (6 h/d and 5 d/wk) to inhalation of 25, 55, 120, 270 or 600 ppm (v/v) p-DCB vapor for 13 wk. The exposure to p-DCB vapor retarded the growth rate in the male mice, and induced hepatotoxicity in the mice and rats of both sexes and renal and hematological toxicity in the male rats. Hepatotoxicity was characterized by increased liver weight, hepatocellular hypertrophy, and increased serum levels of total cholesterol. Liver necrosis and increased serum levels of AST and ALT were observed in the exposed mice, whereas these changes, which indicate hepatocellular death, did not occur in any of the exposed rats. p-DCB-induced renal lesions occurred only in the male rats. Hyaline droplets were observed in the proximal tubular epithelial cells, and were stained positively with anti-alpha2u-globulin, suggesting excessive accumulation of alpha2u-globulin in the epithelial cells. Granular casts were formed in the tubular lumen, resulting from the necrotic desquamation of the renal tubular epithelium. Papillary mineralization in the renal pelvis and increased serum levels of BUN and creatinine were noted. These renal changes indicated alpha2u-globulin nephropathy. Decreases in red blood cell counts, hemoglobin concentration, hematocrit and mean corpuscular volume and increased spleen weight occurred in the exposed male rats. The NOAEL was 120 ppm for the hepatic endpoint in mice and for the renal endpoint in rats. The maximum tolerated dose for a 2-yr bioassay inhalation study of rodent carcinogenicity was estimated to be 300 ppm, based on the present results.     

Thirteen-week inhalation toxicity of carbon tetrachloride in rats and mice

Subchronic toxicity of carbon tetrachloride (CCl4) was examined by inhalation exposure of F344 rats and BDF1 mice of both sexes to 0, 10, 30, 90, 270 or 810 ppm (v/v) CCl4 vapor for 13 wk (6 h/d and 5 d/wk). In the high exposure levels at 270 and 810 ppm, altered cell foci in the livers of both rats and mice, and fibrosis and cirrhosis in the rat liver were observed. Hematoxylin and eosin-stained altered cell foci of rats were recognized as glutathione-S-transferase placental form (GST-P) positive foci, which are preneoplastic lesions of hepatocarcinogenesis. The most sensitive endpoint of CCl4-induced toxicity was fatty change with large droplets in rats of both sexes and male mice, and cytoplasmic globules in male mice, as well as increased relative liver weight in male rats. Those endpoints were manifested at 10 ppm and the LOAEL was determined as 10 ppm for the hepatic endpoints in rats and mice. Enhanced cytolytic release of liver transaminases into plasma in rats and mice and its close association with hepatic collapse in mice were observed at medium and high levels of inhalation exposure. Both CCl4-induced hematotoxicity and nephrotoxicity were observed in both rats and mice, but those toxicities were manifested at higher exposure concentrations than hepatotoxicity. The LOAEL for the hepatic endpoint and the GST-P-stained altered cell foci provide relevant animal data for reconsidering the occupational exposure limit val1ue of 5 ppm for CCl4 and strengthen the evidence of CCl4-induced hepatocarcinogenicity which is used in its carcinogenicity classification.     

Carcinogenicity and chronic toxicity after inhalation exposure of rats and mice to N,N-dimethylformamide

Carcinogenicity and chronic toxicity of N,N-Dimethylformamide (DMF) were examined by inhalation exposure of groups of 50 rats and 50 mice of both sexes to DMF vapor at a concentration of 0, 200, 400 or 800 ppm (v/v) for 6 h/d, 5 d/wk, for 104 wk. In rats, incidences of hepatocellular adenomas and carcinomas significantly increased in the 400 and 800 ppm-exposed groups and in the 800 ppm-exposed group, respectively. The hepatocellular adenoma did not increase significantly in the 400 ppm-exposed female rats, but its incidence exceeded a range of historical control data in the Japan Bioassay Research Center (JBRC). In mice, incidences of hepatocellular adenomas and carcinomas significantly increased in all the DMF-exposed groups. Incidence of hepatoblastomas significantly increased in the 200 and 400 ppm-exposed male mice, and 4 cases of hepatoblastomas in the 400 ppm-exposed female mice and the 800 ppm-exposed male mice exceeded the range of historical control data of the JBRC. Incidences of altered cell foci increased in the liver of exposed rats and mice in an exposure concentration-related manner, and those foci were causally related to the hepatocellular tumors. Liver weights increased in both rats and mice exposed to DMF at 200 ppm and above. Increased levels of gamma-GTP, ALT, AST and total bilirubin in exposed rats of both sexes and AST and ALT in exposed mice of both sexes were noted. It was concluded that 2-yr inhalation exposure to DMF increased incidences of hepatocellular adenomas and carcinomas in rats and incidences of hepatocellular adenomas, carcinomas and hepatoblastomas in mice, and that hepatocarcinogenicity of DMF was more potent in mice than in rats.     

Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in lesions in the rat hippocampus

Tris(2-chloroethyl)phosphate (TRCP), a flame-retardant plasticizer used in plastics, polymeric foams and synthetic fibers, was studied as part of the National Toxicology Program's class study of phosphate flame-retardants. TRCP was administered at 0, 22, 44, 88, 175 and 350 mg/kg to both sexes of rats and 0, 44, 88, 175, 350 and 700 mg/kg to both sexes of mice in both fourteen day repeat dose and sixteen week subchronic studies. Results of these studies showed that TRCP toxicity in the 14-day studies was limited to modest increases in male rat kidney and female rat liver weights. Little evidence of toxicity was observed in mice in the 14 day studies. Toxicity observed in mice in the sixteen week studies was limited to increased liver weights in both sexes and decreased kidney weights in males. Administration of TRCP to rats for sixteen weeks resulted in increased mortality of both males and females, increased liver and kidney weights and a lesion in the hippocampal region of the brain. The lesion observed in rat brain appeared as loss of the pyramidal neurons of the CA1 region of the hippocampus and was both more common and more severe in female rats. This lesion, which was not observed in mice, is unusual for any chemical and is unique for a trialkyl phosphate such as TRCP. It is speculated that this highly directed toxicity of TRCP might be used as a chemical probe to investigate the role of the hippocampus in behavior and other functions.     

Carcinogenicity and chronic toxicity in mice and rats administered vinyl acetate monomer in drinking water

Carcinogenicity and chronic toxicity of vinyl acetate monomer (VA) were examined in male and female Crj:BDF1 mice and F344/DuCrj Rats. Groups of 50 mice and 50 rats of each sex were orally administered VA in drinking water containing 0, 400, 2,000 or 10,000 ppm (g/g) VA for 104 wk. Squamous cell tumors were clearly evident in the upper digestive tract of treated mice and rats, and in the larynx of treated mice of both sexes. In mice, squamous cell carcinomas and papillomas were observed in the oral cavity, esophagus, forestomach and larynx of the 10,000 ppm group, together with basal cell hyperplasia, squamous cell hyperplasia and epithelial dysplasia. In rats, incidences of squamous cell carcinomas and papillomas were increased in the oral cavity of the 10,000 ppm group of both sexes, and an esophagus squamous cell carcinoma was observed in a 10,000 ppm female. Pre-neoplastic hyperplasias were also noted. Mapping of the neoplastic and pre-neoplastic lesions in the oral cavity of the 10,000 ppm group revealed that both the lesions occurred predominantly at Level V in mice and at Level VI in rats. A lower confidence limit of a benchmark dose (BMDL10) of 477 mg/kg/d was obtained from a dose-response relationship between combined incidence of squamous cell carcinomas and papillomas in the oral cavity of mice and rats and the estimated daily VA intakes per body weight, and compared with literature values.     

Toxicity due to 2- and 13-wk inhalation exposures of rats and mice to N, N-dimethylformamide

In order to better characterize the toxicity of N,N-dimethylformamide (DMF) and to provide its basic toxicity data for risk assessment of workers exposed to DMF, F344 rats and BDF1 mice of both sexes were exposed by inhalation (6 h/d x 5 d/wk) to 100, 200, 400, 800 or 1,600 ppm DMF for 2 wk, and 50, 100, 200, 400 or 800 ppm DMF for 13 wk. Three male and 7 female rats died during the 2-wk exposure to 1,600 ppm DMF, but no death of the exposed rats or mice occurred under any other exposure conditions. Massive, focal and single cell necroses were observed in the liver of DMF-exposed rats and mice. The massive necrosis associated with the centrilobular fibrosis occurred at the highest exposure concentration. The single cell necrosis was associated with fragmentation of the nucleoli as well as an increased mitotic figure. The 13-wk exposures of rats and mice to DMF were characterized by increases in the relative liver weight and the incidence of the centrilobular hepatocellular hypertrophy as well as increased serum levels of AST, ALT, LDH, total cholesterol and phospholipid. Lower confidence limits of the benchmark dose yielding the response with a 10% extra risk (BMDL10) were determined for the relative liver weight and the incidence of hepatocellular hypertrophy of the 13-wk exposed animals. The BMDL10 resulted in 1 ppm for the increased relative liver weight of male rats and mice and 17 ppm for the hepatocellular hypertrophy of male mice.     

Toxicity of N-methyl-4-methoxynaphthalimide,a fluorescent whitening agent

Toxicological studies onN-methyl-4-methoxynaphthalimide (MMNI), a water pollutant, were performed on mice for acute toxicity, and on rats for distribution and subacute toxicity. The mutagenicity of MMNI and its metabolites in bacteria was also investigated. Seven days of consecutive administration with MMNI to male rats caused accumulation of MMNI in the adipose tissue, large intestine, and liver. Small amounts of MMNI were detected in the kidneys, spleen, thymus, and serum, and the metabolites of MMNI (C-hydroxide and conjugate) were detected primarily in the serum and liver, although they were rapidly excreted from the body by urinary routes. The LD50 value in male mice by intraperitoneal administration of MMNI was 7,700 mg/kg. No growth retardation was found in rats orally administered for 21 days. Male rats fed on 30,000 ppm and female rats fed on 6,700 or 30,000 ppm of MMNI exhibited slight growth retardation after a 40-day feeding trial. Enlargement of rat livers was seen in the high dose groups (100 mg/day, 6,700 and 30,000 ppm), along with moderate histological changes in liver (such as fatty infiltration, focal necrosis, proliferation of endoplasmic reticulum, and Mallory's bodies). Histological changes were also detected in kidneys (vacuolation and numerous hyalin droplets in the tubules) and pancreas (vacuolation). In these groups, mean amounts of serum protein were elevated, and serum glutamic pyruvic transaminase (SGPT) activities were decreased. Atrophy of thymus was seen in 6,700 and 30,000 ppm group, but immunosuppressive effect was not observed. An increase in the amounts of liver cytochrome P-450 was found in the rats given 10 and 100 mg daily doses of MMNI for 21 days. There was no mutagenic activity of MMNI on theSalmonella typhimurium TA98 and TA 100 with or without S-9 mix, whereas its metabolites present in the urine of rats had slight mutagenic activity on TA100.     

Hyalin droplet nephrosis in male Fischer-344 rats following inhalation of diisobutyl ketone

Four groups, each consisting of 10 male and 10 female Fischer-344 rats, were exposed 6 h/day, 5 days/week, for 9 days to diisobutyl ketone (DIBK) vapor at concentrations of 905, 300, 98, or 0 (control) ppm. An additional 10 rats/sex were assigned to the 905 and 0 ppm groups and allowed two weeks recovery prior to sacrifice. Rats exposed to 905 ppm had mild ocular irritation (lacrimation) and evidence of kidney toxicity, manifested as: 1) an increase in absolute and relative (as a percentage of body weight) kidney weights, 2) an increase in urine volume (and water intake) with a concomitant decrease in urine osmolality (males only), and 3) an increase in severity of hyalin droplet nephrosis in the proximal tubules (males only). Absolute and relative liver weights were also increased in both male and female rats of the 905 and 300 ppm groups. These effects either disappeared or lessened in severity following the 2-week recovery period. Male rats exposed to 300 ppm had similar renal alterations to the males of the 905 ppm group, although the alterations were fewer in number and smaller in magnitude. Kidney weights and renal histology of the males of the 98 ppm group were similar to the control male rats, although an increase in urine volume with a decrease in urine osmolality was observed. The kidney findings in this study were not surprising because of the chemical relationship of DIBK with other aliphatic ketones (e.g., methyl isobutyl ketone, methyl isoamyl ketone) which, after repeated inhalation exposure, cause hyalin droplet nephropathy in male rats. The significance of this male rat nephrosis with regard to human exposure is unknown.     

Sub-acute and sub-chronic toxicity ofmono-2-ethylhexyl phthalate in the rat

Groups of six male Sprague-Dawley rats were administered single oral doses of mono-2-ethylhexyl phthalate (MEHP) at 50, 100 or 200 mg/kg or di-2-ethylhexyl phthalate (DEHP) at 2,000 mg/kg in 2% gum acacia and were observed clinically for seven days. Body weight and food consumption were not affected by treatment. The liver weight increased in the groups receiving 100 mg or 200 mg mono-2-ethylhexyl phthalate and 2,000 mg diethylhexyl phthalate. Hepatic microsomal aniline hydroxylase activity was not altered by treatment.In a subsequent 28-day experiment, groups of ten weanling Sprague Dawley rats were fed diets containing 0, 25, 100, 400, 1,600 or 6,400 ppm of mono-2-ethylhexyl phthalate. Decreased growth rate occurred in the group receiving the highest dose level. Increased heart and liver weights were observed in animals from the 1,600 and 6,400 ppm groups. Minor alterations in serum biochemical values included decreased SDH and calcium levels, and elevated alkaline phosphatase activity in some treated groups. A mild reduction in red cells saturation and hematocrit was noted in some groups.In 3-month and 6-month feeding studies, groups of ten male and female weanling Sprague-Dawley rats were fed diets containing 1, 5, 25, 125 or 625 ppm of mono-2-ethylhexyl phthalate. Growth rate and food consumption were not affected at any dose level or time interval. Relative organ weights of rats of both sexes were not altered in the 3-month period, but the liver weights of female rats in the 6-month experiment were increased. Changes in clinical chemistry and hematological values were mild. These included lower LDH, SGOT, hemoglobin, and hematocrit values in male rats at the 3-month period and reduced potassium content at the 6-month period. Histological changes were mild in both male and female rats at both time intervals. Treatment-related lesions were found in the liver, heart, and adrenals. Alteration in the liver consisted of midzonal and periportal eosinophilic cytoplasmic inclusions and vacuolations with isolated binucleated and necrotic hepatocytes. There was a mild enlargement of myocardial nuclei and segmental deregistration of myocardial striations in test animals. The adrenal glands exhibited vacuolation of the zona fasciculata which was less severe in the 6-month period than the 3-month counterpart. In conclusion, mono-2-ethylhexyl phthalate is similar to its parent compound diethylhexyl phthalate in that it possesses a low order of oral toxicity in rats.     

亚硒酸钠和硒蛋氨酸的毒性比较

目的　比较亚硒酸钠和硒蛋氨酸毒性差异以及探讨硒中毒的指标。方法　将断乳Wistar大鼠随机分为 7组 ,每组 14只 ,雌雄各半。其中一组为对照组 ,另外六组分别给予含硒 3、6、10mg kg的亚硒酸钠或硒蛋氨酸饲料 ,于第 12周将其处死。结果　当饲料硒水平达到 3mg kg时 ,动物肝脏出现病理变化 ,在Se6mg kg时 ,体重才出现下降。饲料硒水平为 6、10mg kg时 ,同一饲料硒水平的亚硒酸钠组大鼠体重小于硒蛋氨酸组。饲料硒水平为 3、6mg kg时 ,硒蛋氨酸组大鼠的肝脏病理改变轻于亚硒酸钠组 ,雄性大鼠轻于雌性。亚硒酸钠组较硒蛋氨酸组或雌性大鼠较雄性大鼠在肝脏体重比方面变化更为明显。除雌性大鼠肝脏谷胱甘肽过氧化物酶 (GPX)活性随硒水平升高而降低外 ,其它补硒各组肝、红细胞、血浆GPX活性具有随硒水平的升高而升高的趋势。结论　大鼠硒中毒的剂量为Se 3mg kg,硒蛋氨酸的毒性小于亚硒酸钠 ,雌性大鼠对硒毒性更为敏感     

杀虫磺原药大鼠亚慢性毒性研究

目的研究杀虫磺原药对大鼠亚慢性经口毒性,探讨其亚慢性毒性的阈作用剂量和最大无作用剂量。方法雌鼠剂量以135、67.50、22.50mg/kg,雄鼠剂量以157.5、78.752、6.25mg/kg,连续90d给予杀虫磺原药,观察动物的一般状况,体重增长及血液、生化指标并解剖进行病理检查。结果杀虫磺原药高剂量组动物,染毒8周后出现被毛蓬松、活动减少、体重减轻等症状;染毒结束后血清中谷草转氨酶（AST）升高,肝及雄鼠肾脏器系数增大,组织病理学检查显示：肝细胞明显浊肿,胞浆疏松,汇管区可见慢性炎细胞浸润。中剂量组动物染毒结束后谷草转氨酶（AST）显著升高,雄鼠肾脏器系数增大;肝细胞病变相同,但程度较轻。低剂量组动物一般行为、体重增长、尿常规、血液学、血液生化学、脏器重量、脏器系数及病理学检查均未见变化。结论本实验条件下,初步确定大鼠90d亚慢性经口最大无作用剂量,雌性为22.50mg/kg;雄性为26.25mg/kg。     

The determination of the repeated oral toxicity of halocarbon oil, series 27-S

Halocarbon 27-S (HC 27-S), a polymer of chlorotrifluoroethylene (CTFE), is used as a lubricating oil for pumps in hyperbaric chambers. Although monomeric CTFE has been shown to produce renal lesions in rats, the toxicity of CTFE polymers have not been investigated. To assess the toxicity of repeated exposure to HC 27-S, three groups (N = 6/group) of male and female Fischer-344 rats were dosed with 2.5 g HC 27-S/kg for 7 or 21 consecutive days. Groups were sacrificed at 7, 21, and 35 days (14 days after the 21-day dosing). Corresponding control groups (N = 6) were dosed with deionized water. Decreased water consumption and urine output were apparent in all test groups. Statistically significant increases in fluoride excretion were noted in 24-hr urine samples assessed periodically during the study. Neurotoxic signs were observed in female rats but not in male rats. Significant increases in liver and kidney weights were seen in all rats, regardless of number of dosing days. The increased fluoride burden in treated animals appeared sufficient to alter bone calcium/phosphate ratios in male rats but not female rats. Gross liver enlargement and hepatocellular cytomegaly indicated that the liver was probably the primary target organ following repeated administration of HC 27-S.     

二氯五氟丙烷的28天吸入毒性试验观察

[目的]研究二氯五氟丙烷(HCFC-225)的毒性及安全性。[方法]通过实验动物急性毒性试验来确定该物质的急性毒性等级，通过大鼠28天吸入毒性试验找出亚急性毒作用浓度闽值及靶器官。急性毒性用霍恩氏法计算；亚急性毒性用不同剂量的该物质对动物染毒，分别对各剂量组的动物进行血液生化测定，称量动物体置、脏器重量并进行组织病理学检查(肺、肝、肾、心)。[结果]小鼠总性LD50雌性为20g／kg，雄性为14．7g/kg；小鼠急性LC50幼为526670mg/m^3；大鼠急性LD50大于21．5g／kg；大鼠28d吸入毒性试验结果提示，AK-225吸入毒作用的主要靶器官为动物的肺脏和肝脏，其次是肾脏。主要的毒性表现有血清中ALT、AST、cR、BUN含量升高；肺组织淤血、出血及炎症细胞浸润；肝组织轻度及水样变病理改变等。最小毒作用浓度(LOEC)为37350mg/m^3，未观察到毒作用浓度(NoEc)为12450mg/m^3。[结论]二氯五氟丙烷(HCFC-25)的急性毒性用于微毒；本次大鼠28d吸入毒性试验结果提示，HCFC—225吸入毒作用的主要靶器官为动物的肺脏和肝脏，其次是肾脏。最小毒作用浓度(LOEC)为37350mg/m^3，未观察到毒作用浓度(NOEC)为12450mg/m^3。     

Fumonisin b1 carcinogenicity in a two-year feeding study using F344 rats and B6C3F1 mice

Fumonisin B1 (FB1) is a mycotoxin isolated from Fusarium fungi that contaminate crops worldwide. A previous study demonstrated that FB1 promoted preneoplastic foci in initiated rats and induced hepatocellular carcinomas in BD IX rats at 50 parts per million (ppm), but fundamental dose-response data were not available to assist in setting regulatory guidelines for this mycotoxin. To provide this information, female and male F344/N/Nctr BR rats and B6C3F1 Nctr BR mice were fed for two years a powdered NIH-31 diet containing the following concentrations of FB1: female rats, 0, 5, 15, 50, and 100 ppm; male rats, 0, 5, 15, 50, and 150 ppm; female mice, 0, 5, 15, 50, and 80 ppm; male mice, 0, 5, 15, 80, and 150 ppm. FB1 was not tumorigenic in female F344 rats with doses as high as 100 ppm. Including FB1 in the diets of male rats induced renal tubule adenomas and carcinomas in 0/48, 0/40, 9/48, and 15/48 rats at 0, 5, 15, 50, and 150 ppm, respectively. Including up to 150 ppm FB1 in the diet of male mice did not affect tumor incidence. Hepatocellular adenomas and carcinomas were induced by FB1 in the female mice, occurring in 5/47, 3/48, 1/48, 19/47, and 39/45 female mice that consumed diets containing 0, 5, 15, 50, and 80 ppm FB1, respectively. This study demonstrates that FB1 is a rodent carcinogen that induces renal tubule tumors in male F344 rats and hepatic tumors in female B6C3F1 mice.     

某品牌碘酒消毒液的急性和亚急性毒性评价

目的对临床用碘酒消毒液进行急性和亚急性毒性评价。方法选择某品牌碘酒消毒液,依据《消毒技术规范》(2002)进行大、小鼠的经口LD50值测定和大鼠经口亚急性毒性试验。结果雌、雄大、小鼠急性经口LD50值均大于5 000 mg/kg,按急性毒性分级,属实际无毒级。连续灌胃29 d后,雌、雄大鼠均未见明显中毒症状,亦未见死亡;对大鼠各阶段体重均无显著影响;对血液学各项检查指标无影响;末期生化检验示雄鼠和雌鼠1 000 mg/kg组的胆固醇较对照组均明显升高(P0.05),但尚在正常值范围内;雌、雄大鼠各剂量组的肝体比、肾体比与对照组相比差异无统计学意义;病理学检查所发现的病变为自发病变,高剂量组未见动物中毒性损伤改变。结论某品牌碘酒消毒液用作皮肤消毒剂,正常使用安全。     

Dietary copper deficiency reduces iron absorption and duodenal enterocyte hephaestin protein in male and female rats

The mechanism for reduced Fe absorption in Cu deficiency is unknown, but may involve the intestinal Cu-dependent ferroxidase, Hephaestin (Hp). A 2 x 2 factorial experiment was designed to include Cu-deficient (CuD) and Cu-adequate (CuA) male and female rats. Weanling rats of both sexes were randomly divided into 2 groups each and fed an AIN-93G diet with low (<0.3 mg/kg; CuD) or adequate Cu (5.0 mg/kg; CuA). After 19 d, rats were fed 1.0 g each of their respective diets labeled with (59)Fe. Retained (59)Fe was monitored by whole-body counting for 12 d. Then, rats were killed for (59)Fe and Fe measurements in blood and various organs. Duodenal enterocytes were isolated for Western blot analysis of Hp. Signs of Cu and Fe deficiency were evident in both sexes. CuD male rats absorbed 60% as much Fe as CuA male rats (P < 0.001), whereas CuD female rats absorbed 70% (P < 0.001) as much as CuA females, with no difference between the sexes. Hp protein in enterocytes of CuD rats of both sexes was only 35% of that in CuA rats. The biological half-life of (59)Fe in CuD rats was only 50% (P < 0.001) of that in CuA rats, suggesting that Fe turnover was faster in CuD rats than CuA rats. Serum, spleen, and kidney Fe were lower (P < 0.001) in CuD rats than in CuA rats. Duodenal mucosa and liver Fe were higher (P < 0.01) in CuD male rats than CuA rats. Duodenal Fe but not liver Fe was higher in CuD female rats than CuA rats. Liver Fe was much higher (<0.001) overall in females than males. The data suggest that Cu deficiency reduces Fe absorption in rats through reduced expression of duodenal Hp protein.     

Compensatory regeneration as a mechanism for renal tubule carcinogenesis of fumonisin B1 in the F344/N/Nctr BR rat

Fumonisin B1(FB1) is a fungal metabolite of Fusarium verticillioides (= F. moniliforme), a fungus that grows on many crops worldwide. Previous studies demonstrated that male BD IX rats consuming diets containing 50 ppm fumonisin B1 developed hepatocellular carcinomas. In our recent studies, diets containing FB1 at 50 ppm or higher concentrations induced renal tubule carcinomas in male F344/N/Nctr BR rats and hepatocellular carcinomas in female B6C3F1/Nctr BR mice. The carcinogenicity of FB1 in rats and mice is not due to DNA damage, as several laboratories have demonstrated that FB1 is not a genotoxin. FB1 induces apoptosis in cells in vitro. Including FB1 in the diets of rats results in increased hepatocellular and renal tubule epithelial cell apoptosis. In studies with F344/N/Nctr BR rats consuming diets containing up to 484 ppm FB1 for 28 days, female rats demonstrated more sensitivity than male rats in the induction of hepatocellular apoptosis and mitosis. Conversely, induction of renal tubule apoptosis and regeneration were more pronounced in male than in female rats. Induction of renal tubule apoptosis and hyperplasia correlated with the incidence of renal tubule carcinomas that developed in the 2-year feeding study with FB1 in the F344/N/Nctr BR rats. The data are consistent with the hypothesis that the induction of renal tubule carcinomas in male rats could be partly due to the continuous compensatory regeneration of renal tubule epithelial cells in response to the induction of apoptosis by fumonisin B1.     

黄芩苷对雄性大鼠肝肾毒性作用研究

目的:观察不同剂量黄芩苷给药不同时间对大鼠肝肾的毒性作用,为临床用药的安全性提供实验参考依据。方法:于2019年4月,将42只Wistar雄性大鼠随机分为对照组（0.9%氯化钠溶液,14只）和黄芩苷给药组（100、200 mg/kg,各14只）,经口灌胃,1次/d,6次/周,于给药28、56 d后各组分别处死7只大鼠,...