Effects of Folic Acid and Folinic Acid on Pyrimethamine Teratogenesis in Rats

Abstract The effects of folic acid (FA) and folinic acid (FNA) on the teratogenicity of the antifolate drug pyrimethamine (PYR) were examined in rats. PYR and FA were orally administered with mashed feed. FNA was intraperitoneally injected. The drugs were administered for 5 days of day 11–15 of gestation. Six groups were made; G-I PYR 1.6 (mg/kg/day), G-II PYR 3.6, G-HI PYR 1.6 + FA 50, G-IV PYR 3.6 + FNA 12, G-V FA 50, G-VI control. No malformations were found in G-I, IV, V and VI. All fetuses in G-II and III had malformations. Main malformations in G-II and III were cleft palate and brachygnathia. Accordingly it might be demonstrated that the teratogenicity of PYR was potentiated by concurrent FA in rats.     

Effects of Folic Acid and Folinic Acid on Pyrimethamine Teratogenesis in Rats

ABSTRACT  The effects of folic acid (FA) and folinic acid (FNA) on the tera-togenicity of the antifolate drug pyrimethamine (PYR) were examined in rats. PYR and FA were orally administered with mashed feed. FNA was intraperitoneal-ly injected. The drugs were administered for 5 days of day 11–15 of gestation. Six groups were made; G-I PYR 1.6 (mg/kg/day), G-II PYR 3.6, G-HI PYR 1.6 + FA 50, G-IV PYR 3.6 + FNA 12, G-V FA 50, G-VI control. No malformations were found in G-I, IV, V and VI. All fetuses in G-II and HI had malformations. Main malformations in G-II and III were cleft palate and brachygnathia. Accordingly it might be demonstrated that the teratogenicity of PYR was potentiated by concurrent FA in rats.     

Ameliorative Effect of Folic Acid on Pyrimethamine Teratogenesis in Pigs

Abstract The effects of oral dosing of folic acid (FA) on pyrimethamine (PYR) teratogenesis were examined in Goettingen minipigs. PYR (3.6 mg/kg/day) was orally administered in the feed to sows with or without FA (2.5, 10 or 50 mg/kg/day) for 12 days, (days 11 - 22 of gestation). Major malformations, such as cleft palate, cleft lips, micrognathia and clubfoot, were observed in all treated groups. The incidence of malformed fetuses decreased dose-dependently as the FA level was raised. This new finding suggests FA administration may prevent newborns from PYR induced malformations. This result contrasts in the observations in rats, in which PYR teratogenesis was potentiated by the concurrent oral dosing of FA. Neither PYR blood concentrations nor plasma protein binding was significantly affected by FA dosing in nonpregnant sows. These results suggest a mechanism other than pharmacokinetic modification was responsible for the protective effect of FA on PYR teratogenesis in minipigs.     

Potentiated Embryotoxicity of Pyrimethamine by Folic Acid in Mice

ABSTRACT Effects of folic acid (FA) and folinic acid (FNA) on the embryotoxicity of pyrimethamine (PYR), an antifolate drug, were examined in mice. PYR and FA were administered orally, and FNA was injected intraperitonially for 7 days from day 9 to 15 of pregnancy. The incidence of embryotoxicity including intrauterine deaths and malformations, was 33.5 % in the PYR 50 mg/kg/day group. However, all the fetuses were resorbed in the PYR 50 + FA 50 mg/kg/day group, and FA potentiated the embryotoxicity of PYR. On the contrary, FNA reduced the embryotoxicity of PYR (PYR 50 + FNA 10mg/kg/day; 8.5%). Plasma concentrations of PYR and 5-methyltetrahydrofolic acid (5MF), a principal form of folate in plasma, were determined after single oral administration of PYR 50 mg/kg with or without FA 50 mg/kg to non-pregnant mice. Plasma 5MF concentration decreased drastically in the group receiving PYR with FA, compared with the PYR alone group. The pharmacokinetics of PYR were not affected by co-administration of FA. Therefore, we consider that the potentiated embryotoxicity of PYR by oral FA results from a decrease of plasma 5MF concentration in dams.     

Effect of Folic Acid on Pharmacokinetics of Pyrimethamine in Rats

The effect on pyrimethamine (PYR) pharmacokinetics of folic acid (FA) which potentiated the PYR teratogenesis was studied in rats. Gavage administration of PYR 1.6 mg/kgBW/day from day 11 to day 15 of gestation did not cause any malformation, but with concomitant dosing of FA 50 mg/kg/day in feed caused malformations in 75% of fetuses. Neither the plasma concentration-time profile nor the plasma protein binding of the gavaged PYR was affected by the concomitant dosing of FA in the non-pregnant rats. The pregnant rats which received the gavaged PYR with or without FA in feed for 5 days (from day 11 to day 15 of gestation) were killed at 4 or 12 hrs after the last dosing of PYR, and their plasma and fetuses were subjected to determination of PYR. The PYR concentration in the maternal plasma was comparable in both groups. The PYR concentration in fetuses of the PYR alone group was significantly higher than that of the PYR with FA group 4 hr after but not 12 hr after the last dosing. These results indicated that the pharmacokinetics of PYR was not affected by the concomitant dosing of FA, suggesting that FA potentiated the PYR teratogenesis by other mechanisms than pharmacokinetic modifications.     

Effects of Pyrimethamine and Folic Acid on Plasma Level of 5-Methyltetrahydrofolic Acid in Rats

Abstract: The relationship between pyrimethamine (PYR) teratogenesis and the plasma level of 5-methyltetrahydrofolic acid (5MF), known as an active form of folate in plasma, was studied in rats using an HPLC-ECD method for 5MF determination. The rat received, for 5 days, in-feed PYR with or without folic acid (FA), which was previously reported as a potentiator of PYR teratogenesis. PYR alone caused a dose-dependent decrease in the plasma 5MF level after the 5 day dosings. A potentiated decrease in the 5MF level was observed after the concomitant dosing of PYR with FA. The concomitant dosing of PYR 1.6 mg/kgBW/day (subteratogenic dose of PYR alone) with FA 50 mg/kg/day, which was 100% teratogenic dose in our previous report, decreased the 5MF level more than that after the dosing of PYR 3.6 mg/kg/day alone (100% teratogenic dose of PYR alone).
The sequential changes of the plasma 5MF level after the single oral dosing of PYR 3.6 mg/kg with or without oral FA 50 mg/kg also revealed a strong potentiative effect of oral FA on the 5MF-level-lowering effect of PYR. These results indicate that a decrease in the plasma 5MF level may be related to PYR teratogenesis.     

Pyrimethamine Teratogenesis by Short Term Administration in Goettingen Miniature Pig

Pyrimethamine was mixed with mashed feed and given to pregnant sows of Goettingen miniature pig through a part of the period of organogenesis. A high incidence of the major malformations such as cleft palate, club foot and micrognathia was observed in 13 out of 24 newborns from 5 pregnants which a teratogenic dose (3.6 mg/kg of body weight/day) from day 11 to day 22 of gestation, the first half of the organogenetic period. Only one cleft palate was observed among the 23 newborns from 4 pregnants administered the same dose through the second half of the period. Among the 51 newborns from 10 pregnants which the same dose through the first or second quarter, only 4 newborns showed external major malformations. However, 19 out of 38 live newborns without external major malformations in these groups died within 2 days after birth. Clinical symptoms of these neonatally dead young were similar to splayleg, a naturally occurring functional anomaly in pigs. No internal malformation was revealed by the autopsy of these dead newborns.     

氯化甲基汞对大鼠行为致畸作用的影响

目的　为研究氯化甲基汞的染毒大鼠对其后代的行为致畸作用。方法　对 4组受孕大鼠腹腔注射氯化甲基汞 ,每次剂量分别为 0、0 .75、1.5 0、3 .0 0mg/kg ,待其自然分娩后观察其子代生长发育及行为状态。结果　其子代生长发育及行为功能部分指标延迟。结论　氯化甲基汞具有行为致畸作用。     

托吡酯联合叶酸对戊四氮致癫(癎)幼鼠海马神经元线粒体损伤的保护作用

目的探讨托吡酯(TPM)联合叶酸(FA)对慢性癫幼鼠海马CA3区神经元线粒体超微结构损伤的影响。方法将3周龄雄性Wistar大鼠随机分为阴性、阳性对照组、TPM组和TPM加FA组。予各组大鼠戊四氮(PTZ)腹腔注射,制造慢性癫模型,分别予等量蒸馏水、TPM40mg/(kg·d)和TPM40mg/(kg·d)加FA5mg/(kg·d)灌胃;阴性对照组先行9g/L盐水腹腔注射,再予等量的蒸馏水灌胃。连续用药2个月。观察各组行为学表现及海马CA3区神经元线粒体的超微结构。结果TPM和TPM加FA组大鼠惊厥发作次数及海马CA3区神经元线粒体的超微结构损伤程度较阳性对照组明显减轻。阳性对照、TPM和TPM加FA组的惊厥发作次数依次为:(48.4±3.7)、(44.3±3.1)、(40.8±3.7)次,3组间差异有统计学意义(Pa<0.01);阴性对照、阳性对照、TPM、TPM加FA组海马CA3区神经元线粒体的超微结构损伤程度依次为(0.34±0.09)、(3.76±0.28)、(2.85±0.21)、(2.09±0.31)级,4组间差异有统计学意义(Pa<0.01)。结论TPM对慢性癫发作所致的海马神经元线粒体损伤有保护作用,FA可加强TPM的线粒体保护作用。     

叶酸对人T淋巴细胞性白血病细胞体外的作用

目的探讨叶酸对人T淋巴细胞性白血病细胞株(CEM)细胞的作用。方法1.四氮甲基唑蓝(MTT)法检测叶酸不同浓度.不同作用时间对CEM细胞增殖影响;2光镜下观察不同浓度叶酸作用于CEM细胞24、48、72 h细胞形态变化;3.流式细胞术检测叶酸持续作用于CEM细胞48 h细胞凋亡率、细胞周期分布及细胞表面凋亡相关蛋白Bcl-2、C-myc表达;4.DNA 电泳分析凋亡细胞DNA片段化的生化改变;5.MTT法检测叶酸对甲氨蝶呤(MTX)抗肿瘤作用影响。结果1叶酸对CEM 的增殖有明显抑制作用,在(0 4～3.0)×10-4μg/L时抑制作用最明显,抑制率30%～40%;2.叶酸分别作用于CEM细胞24、48、72 h后,光镜下可见CEM细胞出现典型的细胞凋亡各阶段的变化,在浓度为(0 2～6.0)×10-4 μg/L均可见到凋亡细胞, 尤其在(0 4～3.0)×10-4 μg/L凋亡率较高;3流式细胞术分析,叶酸浓度为3 0×10-4 μg/L时诱导凋亡作用最强,凋亡率为6.19%,CEM细胞经叶酸处理后细胞周期无明显变化规律,但叶酸作用于CEM细胞48 h,在Pl荧光的直方图上可见凋亡细胞在G1/G0期前出现一亚二倍体峰,细胞表面凋亡相关蛋白Bcl-2、C-myc表达率均明显下降;4.CEM细胞经0 4×10-4 μg/L和3.0×10-4 μg/L 叶酸处理48h,提取DNA电泳,可见典型的梯状条带;5.叶酸在浓度为(0.2～12.0)×10-4 μg/L 不影响     

叶酸缺乏对孕鼠子代心脏中NKx2.5基因表达的影响

目的探讨叶酸缺乏孕鼠子代心脏发育过程中NKx2.5基因和蛋白表达改变。方法成熟雌性36只SD大鼠随机分为实验组和对照组各18只,分别喂以缺乏叶酸和添加叶酸的纯合饲料。2周后与成熟SD雄性大鼠交配,分别取孕13.5 d、孕17.5 d胚胎鼠及新生鼠心脏。用RT-PCR检测NKx2.5基因mRNA表达。Western-blotting测GATA-4蛋白表达水平。结果NKx2.5基因mRNA及其蛋白在孕13.5 d、孕17.5 d胚胎心脏及新生鼠心脏中的表达量,实验组均显著低于对照组(P均<0.05)。结论叶酸缺乏影响NKx2.5基因和蛋白表达水平,可能导致心脏发生发育中形态改变,从而造成心脏功能缺陷。     

Male-Mediated Developmental Toxicity: Enhanced Susceptibility to Induced Teratogenesis in the Offspring of Male Mice Treated with Ethylnitrosourea

Male ICR strain mice were injected intraperitoneally with ENU at 50 mg/kg daily for 5 days and mated to untreated virgin females of the same strain on days 64–80 after the last dose. Copulations during this period involved spermatogonial stem cells at the time of the last treatment. Subsequently, copulated females were injected intraperitoneally with ENU at 25–100 mg/kg on day 8 of gestation, at 50–200 mg/kg on day 12 of gestation or injected subcutaneously with triamcinolone acetonide at 1.25–10 mg/kg on day 12 of gestation. The uterine contents were examined on day 18 of gestation. Fetuses of dams treated on day 8 of gestation were inspected for external and skeletal abnormalities, and those of dams treated on day 12 were inspected for external abnormalities including cleft palate. Frequencies of microphthalmia and cleft palate in the group in which females mated with ENU-treated males were treated with ENU at 50 mg/kg on day 8 of gestation or with ENU at 50 mg/kg on day 12 of gestation, respectively, were significantly higher than those in the group in which females mated with phosphate buffer-treated males were treated with ENU at 50 mg/kg on day 8 or at 50 mg/kg on day 12. No significant increases in the frequency of cleft palate were observed in the groups in which females mated with ENU-treated males were treated with triamcinolone acetonide on day 12 of gestation as compared with groups in which females mated with phosphate buffer-treated males were treated with triamcinolone acetonide on day 12 of gestation. These results suggested the increased susceptibility to induced teratogenesis (congenital malformations induced by exposure of embryo/fetus during gestation) in the offspring derived from paternal germ cells treated with the potent mutagen ENU, but not the non-mutagen triamcinolone acetonide.     

The Impact of Gluten on Haematological Status, Dietary Intakes of Haemopoietic Nutrients and Vitamin B12 and Folic Acid Absorption in Children with Coeliac Disease

ABSTRACT. The haematological status, as well as the fractional absorptions of folic acid-and of vitamin B₁₂ (FAFol and FAB₁₂) were studied longitudinally in 20 coeliac children aged 1.2-16.6 yr (mean 7.5 yr) during periods of gluten-free and gluten containing diets. The absorption methods were specially adapted to use in children, and age-related reference limits were established. Also, dietary intakes of iron, folate and B₁₂ were registered. The haemoglobin concentrations did not show any significant differences in relation to shifts in diet. A few had mild anaemia while the haemoglobin concentrations in the other patients remained within normal range. The iron status, as judged from mean corpuscular volume (MCV), serum (S)-iron, S-transferrin and saturation %, appeared to be generally insufficient. However, the only significant change related to shifts in diet was an increase of S-iron during the first period of gluten-free diet. Dietary intakes of iron proved to be insufficient, regardless of the type of diet. Plasma (P)-B₁₂ concentrations demonstrated a wide range of values above the lower normal limit, whereas the level in a single patient was within the “intermediate range” of B₁₂ insufficiency (150-200 pmol/l). The folate status (erythrocyte-folate) showed significant variations related to dietary changes. However, few patients were folate depleted. FAFol and FAB₁₂ demonstrated rapidly occurring, and significant decreases and increases in relation to gluten challenge and gluten-free diet, respectively. Bacterial overgrowth of the small intestinal tract was not found to be a plausible cause of the B₁₂ malabsorption in the case of 5 patients observed. In conclusion, it is recommended that the dietary management of coeliac patients with regard to haemopoietic nutrients focus on an appropriate iron intake. While a few patients failing to keep a strict gluten-free diet risk folate depletion due to malabsorption and to inadequate intake, these patients are, on the other hand, unlikely to develop vitamin B₁₂ deficiency.     

Folic acid in the treatment of acute watery diarrhoea in children: a double-blind, randomized, controlled trial

One-hundred and six male children aged 6-23 months with a history of acute watery diarrhoea of less than 72 h duration were randomized to receive either folic acid in a dose of 5 mg at 8-h intervals or placebo for 5 d. There were 54 children in the folic acid group and 52 in the placebo group. The admission characteristics were comparable between the two groups. No significant differences were observed in the intake of oral rehydration solution or stool output between the groups. The mean ± SD of total stool output (g kg⁻¹) was 532 ± 476 vs 479 ± 354 and the duration (h) of diarrhoea was 108 ± 68 vs 103 ± 53 in the folic acid vs placebo group, respectively. The findings, therefore, should have a positive influence on preventing the inappropriate use of folic acid in acute diarrhoea.     

Folate of pregnant women after a nationwide folic acid supplementation in China

Folate insufficiency during the periconceptional period increases the risk of neural tube defects (NTDs) in offspring, and folic acid supplementation substantially reduces the risk. Widespread large‐scale folic acid supplementation (0.4‐mg folic acid tablet) has been adopted as a main strategy to prevent NTDs in China since 2009. We examined folate concentrations in plasma and red blood cells (RBCs) of pregnant women and the factors associated with blood folate concentrations in a population with a high prevalence of NTDs in northern China. A cross‐sectional survey was conducted in 2014, and 1,107 pregnant women were recruited from 11 county or city maternal and child health centres across Shanxi province. Microbiological assays were used to determine folate concentrations. Factors associated with blood folate insufficiency were identified. The median (25th and 75th percentiles) folate concentrations were 28.4 (17.6, 45.2) nmol L^?1 and 1,001.2 (658.7, 1,402.5) nmol L^?1 in plasma and RBCs, respectively. According to the proposed RBC (906 nmol L^?1) concentrations for optimal NTD prevention, 42.4% participants had RBC folate insufficiency. Rural women had a higher proportion of folate insufficiency than urban women. Folic acid supplementation was the only factor associated with RBC folate insufficiency. A large proportion of women had RBC folate concentrations that are not optimal for the prevention of NTDs despite free access to folic acid supplements. Actions that aim to improve folic acid supplementation compliance are needed to reach the full potential of the nationwide folic acid supplementation programme in terms of NTD prevention.     

地塞米松对缺氧缺血新生大鼠脑组织兴奋性氨基酸和单胺类神经递质的影响

目的观察地塞米松(DEX)对缺氧缺血新生大鼠脑组织兴奋性氨基酸(EAA)和单胺类神经递质含量的影响,探讨其在HIE致脑损伤中的作用。方法建立HIE动物模型,应用高效毛细管电泳和荧光分光光度法,分别检测假手术组、HIE组、小剂量DEX干预组(0.5 mg/kg)及大剂量DEX干预组(10 mg/kg)脑组织EAA及单胺类神经递质含量。结果HIE组EAA及单胺类神经递质含量均较假手术组明显升高(P均<0.01);小剂量DEX组EAA及单胺类神经递质含量与HIE组无明显变化(P>0.05);大剂量DEX组EAA含量较HIE组明显减少(P<0.01),较小剂量DEX组减少(P<0.05);大剂量DEX组单胺类神经递质含量较HIE组及小剂量DEX组均明显降低(P均<0.01)。结论缺氧缺血促进脑组织EAA及单胺类神经递质的释放;大剂量DEX干预可能通过抑制EAA及单胺类神经递质的释放,对HIE脑损伤起保护作用。     

神经生长因子对红藻氨酸致大鼠海马神经细胞半胱氨酰天冬氨酸蛋白酶-3表达的影响

目的观察神经生长因子(NGF)对红藻氨酸(KA)致大鼠海马半胱氨酰天冬氨酸蛋白酶-3(Caspase-3)表达的影响,探讨其对癫大鼠神经细胞的保护作用及其机制。方法将60只日龄21～30 d健康大鼠随机分为9 g.L-1盐水对照组(A组),KA致模型对照组(B组),NGF治疗组(C组),每组20只。KA用9 g.L-1盐水配成2 g.L-1,B组、C组大鼠以4 mg.kg-1腹腔注射。注射完观察记录其性发作的潜伏期和性发作的级别,并进行EEG和病理学检查。C组每只大鼠腹腔注射KA20～30 min予NGF4μg.kg-1腹腔注射。A组用9 g.L-1盐水2 mL.kg-1灌胃和腹腔注射。分别于KA注射6 h、1 d、3 d时将各组大鼠处死5只,常规方法灌注固定,制作冷冻切片。用免疫组织化学染色SP法检测大鼠海马Caspase-3表达,并用HPIAS-2000显微图像定量分析系统进行定量分析。结果B组、C组大鼠注射KA后30 min左右开始出现性发作,EEG和病理学检测均显示癫发作特征。C组大鼠注射3 d后,Caspase-3阳性神经元计数为7.10±2.80,B组为18.40±3.86;A组为0...     

Folic acid in the prevention of neural tube defects: Awareness among laywomen and healthcare providers in Japan

It is known that neural tube defects are folic acid preventable congenital anomalies. We investigated to what extent this information was disseminated among laywomen and healthcare providers. Questionnaire studies were conducted twice, in 2002 and 2007, for four groups of laywomen and seven groups of healthcare providers in Japan regarding awareness, folic acid supplements and healthy diets. Awareness among laywomen was less than 20%, except for families who had experience with spina bifida in 2002, and 5 years later only pregnant women showed a significant increase in awareness. Awareness among healthcare providers varied from 12 to 76%, depending on their profession, and this proportion increased in five of the seven groups in 2007. The majority of laywomen obtained their information from mass media, while the majority of healthcare providers received information through media for professionals. Laywomen who used folate supplements and healthcare providers who recommended them were initially fewer than 25 and 37%, respectively. Five years later, however, pregnant women who used folic acid supplements increased from 9.1 to 43.1%. As awareness among non-pregnant laywomen and some healthcare providers is considerably low, information should be presented repeatedly to these groups. The difficulty in getting women to consume folic acid supplements is an argument for the government to require folic acid fortification of grains so that the prevention of neural tube defects can be maximized.     

叶酸对托吡酯幼鼠脑神经元保护作用的影响

目的 探讨叶酸(FA)对托吡酯(TPM)幼鼠脑神经元保护作用的影响.方法 将3周龄雄性 Wistar大鼠随机分为4组.阳性对照组、TPM组和FA TPM组先行戊四氮(PrZ)腹腔注射制造幼鼠慢性癫疴模型,再分别给予等量蒸馏水、TPM 40 mg/(kg·d)和FA 5 mg/(kg·d) TPM 40 mg/(kg·d)灌胃;阴性对照组先行生理盐水腹腔注射,再给予等量的蒸馏水灌胃.连续用药2个月,观察大鼠行为、血清神经元特异性烯醇化酶(NSE)及海马区病理改变.结果 TPM组和FA TPM组大鼠惊厥发作次数、血清NSE水平及海马区神经元死亡程度明显轻于阳性对照组.FA TPM组与TPM组血清NSE水平比较,差异无统计学意义;FA TPM组海马区坏死神经元百分比明显低于TPM组.结论 FA可加强TPM的幼鼠脑神经元保护作用.     

黄芪皂甙Ⅳ对大鼠心肌成纤维细胞胶原影响

目的探讨黄芪皂甙Ⅳ（XGA）对大鼠心肌成纤维细胞胶原影响及其量效和时效关系。方法采用胶原酶（胰蛋白酶消化法分离大鼠心肌成纤维细胞（FBC）,建立FBC培养系统。在FBC培养系统内加入不同质量浓度和不同作用时间的XGA,提取RNA后用反转录PCR（RT-PCR）法检测Ⅰ、Ⅲ、Ⅳ型胶原,基质金属蛋白酶（MMP-1、-2、-9）及其抑制剂（TIMP-1、-2）mRNA的表达水平。结果予不同水平和不同作用时间XGA后,FBC培养系统RT-PCR产物凝胶电泳显示有Ⅰ、Ⅲ、Ⅳ型胶原,MMP-1、-2、-9、TIMP-1和-2mRNA表达;与予XGA前比较,Ⅰ、Ⅲ、Ⅳ型胶原,TIMP-1、-2mRNA表达水平有所下降,而MMP-1、-2、-9mRNA表达水平有所上升,且随着XGA剂量增加或作用时间延长而渐下降或上升。Ⅰ、Ⅲ、Ⅳ型胶原,TIMP-1、-2mRNA表达水平与XGA的剂量和作用时间呈负相关（r=-0.927~-0.637P=0~0.024）;MMP-1、-2、-9mRNA表达水平与XGA剂量和作用时间呈正相关（r=0.672~0.962P=0~0.034）。结论XGA可减少心肌成纤维细胞胶原形成,其机制可能为抑制胶原的合成、增加胶原降解。