Effects of retinoic acid exposure in utero on mouse vibrissal follicle development

It is known that topical all-trans-retinoic acid (RA) modulates growth and differentiation of skin and its cutaneous appendages. To examine whether a pre-natal exposure to a potentially non-teratogenic dosage of all-trans-RA had any effect on vibrissal follicle development, the histologic and immunohistochemical responses to RA during its morphogenesis in NMRI mouse were investigated. After a single oral dose of 30 mg/kg body weight of all-trans-RA on day 11.5 of gestation, no fetal malformations were detected and the histological features and the distribution of keratin (K) proteins in comparable stages of vibrissal development were similar for the untreated, vehicle-treated and RA-treated mice. The absence of teratogenic response and of adverse effects on the vibrissae under the experimental conditions indicates that this protocol may be useful for investigation of the effects of pre-natal exposure to RA on the post-natal development of experimental tumours in the mouse skin.     

毛囊发育与周期性生长的调控信号通路研究进展

毛囊是皮肤的重要附属结构,也是控制哺乳动物被毛生长的重要器官.哺乳动物出生后,毛囊具有终生呈周期性生长的特性,毛囊干细胞、毛乳头细胞、毛母质细胞及脂肪细胞等参与了毛囊周期性生长,Wnt、BMP、Notch等信号通路与毛囊生长发育密切相关.本文从哺乳动物毛囊的结构、周期性生长特征以及参与毛囊周期性生长调控的相关信号通路等...     

Effects of photoperiod on circadian clock genes in skin contribute to the regulation of hair follicle cycling of Inner Mongolia white cashmere goats

This study investigated how the effects of photoperiod on circadian clock genes in the skin contribute to the regulation of hair follicle cycling of Inner Mongolia white cashmere goats. Twenty‐four female (non‐pregnant) Inner Mongolia white cashmere goats aged 1 ? 1.5 years old with similar live weights (mean, 20.36 ± 2.63 kg) were randomly allocated into two groups: a natural daily photoperiod group (NDPP group:10 ? 16 hr Light, n = 12) and a short daily photoperiod group (SDPP group: 7 hr Light:17 hr Dark, n = 12). All goats were housed in individual pens from May 15 to October 15, 2015 and were fed the same diets. We detected the mRNA expression of brain and muscle arnt‐like protein‐1 (Bmal1), circadian locomotor output control kaput (Clock), cryptochrome‐1 (Cry1), period homolog‐1 (Per1) and Rev‐erbα genes in the goat skin. ANOVA revealed a significant 24 hr (10:00 hr, 14:00 hr, 18:00 hr, 22:00 hr, 02:00 hr, 06:00 hr, 10:00 hr) variation between the SDPP and NDPP groups for three months (July, September, and October). In summary, the current results confirm that an intrinsic oscillating molecular clock exists in goat skin, and that the clock is important for potential timing mechanisms at the anagen phase of hair follicles, which would contribute to the regulation mechanisms of hair follicle cell proliferation.     

Effects of different lipid sources on intake,digestibility and purine derivatives in hair lambs

An experiment was conducted to evaluate the effects of different lipid sources on the nutrient intake, digestibility and purine derivative excretion of lambs. Thirty‐five 60‐day‐old, male, non‐castrated Santa Ines lambs with an initial average body weight (BW) of 13.00 ± 1.80 kg were used in a randomized complete block design with seven blocks and five treatments. The experimental treatments consisted of a control diet without supplemental lipids and four test diets with different lipid supplements, selected according to the degree of ruminal protection from hydrogenation: supplementation, being supplementation with whole cottonseed (WC), supplementation with cashew nut meal (CNM), supplementation with both cottonseed and cashew nut meal (WC‐CNM) and supplementation with calcium salts of long‐chain fatty acids (Ca‐LCFA). The lambs were slaughtered after reaching 28 kg average BW for each treatment. The ether extract intake (EEI) was higher (p < 0.01) for the lipid supplemented compared to control diet lambs. Supplementation with WC decreased the digestibility of dry matter (DM), organic matter (OM), neutral detergent fibre (NDF) and total carbohydrate (TC) (p < 0.01), whereas supplementation with CNM, WC‐CNM and Ca‐LCFA reduced non‐fibrous carbohydrate (NFC) digestibility (p < 0.01). The ether extract (EE) digestibility coefficient was higher with CNM, followed by Ca‐LCFA and WC, when compared to WC‐CNM and control diets. Nitrogen balance (NB) was not influenced (p > 0.05) by the different lipid sources. A lower purine derivative (PD) excretion and thus lower microbial protein supply (MPS) was observed for animals supplemented with Ca‐LCFA (p < 0.01) compared to the WC‐CNM and control diets. In conclusion, WC, CNM and WC‐CNM supplementation did not have negative effects on MPS, although negative effects have been observed on nutrient digestibility.     

Effects of in utero and lactational exposure to the no-observed-adverse-effect level (NOAEL) dose of the neonicotinoid clothianidin on the reproductive organs of female mice

Recently, developmental exposure to clothianidin (CLO) has been shown to cause reproductive toxicity in male mice, but the effects in female mice remain to be clarified. Pregnant C57BL/6N mice were given a no-observed-adverse-effect-level (NOAEL) dose of CLO until weaning. We then examined ovaries of 3- or 10-week-old female offspring. In the CLO-administered group, morphological changes, a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 (GPx4), and activation of genes in the steroid hormone biosynthesis pathway were observed in 3-week-old mice, and decreases of GPx4 immunoreactivity, 17OH-progesterone and corticosterone levels were observed in 10-week-old mice, along with high rates of infanticide and severe neglect, providing new evidence that developmental exposure to CLO affects juvenile and adult mice differently.     

地塞米松、油酸、乳酸对体外培养脂肪细胞HSL活性的影响

为了研究地塞米松、油酸、乳酸对体外培养的脂肪细胞激素敏感脂肪酶（HSL）活性的影响,以体外培养生长良好脂肪细胞为实验模型,培养介质中分别添加0、10、20、40、80、160mg／I。的地塞米松,0、0．5、1．0、1．5、2．0、2．5mmol／L的油酸,0、10、20、30、40、50mg／L的乳酸,培养24h后提取总蛋白,每个处理3个重复,分别采用脂肪酶测定试剂盒检测HSL活性。结果表明,添加乳酸、油酸可抑制HSL的活性,随添加浓度增加,其抑制作用增强;地塞米松对HSL活性有促进作用,且存在剂量依赖性。     

牛磺鹅去氧胆酸对小鼠机体cAMP和cGMP含量的影响

为了研究牛磺鹅去氧胆酸(TCDCA)对小鼠机体环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)含量的影响,试验用环孢菌素A诱导特异性免疫低下模型,按相应组别对应的剂量对小鼠灌胃给药7 d,获取血清;体外培养正常小鼠腹腔巨噬细胞,用MTT方法筛选TCDCA作用于腹腔巨噬细胞的最佳药物浓度;用最佳药物浓度作用于巨噬细胞后超声破碎,获取上清液;ELISA方法测定血清和上清液中cAMP和cGMP的含量。结果表明:在TCDCA高剂量(0.2 g/kg)组小鼠血清中,cAMP含量极显著高于环孢菌素A组(P<0.01);各组小鼠血清cGMP含量差异不显著(P>0.05);TCDCA促进小鼠腹腔巨噬细胞增殖的体外浓度为1μg/mL、2.5μg/mL、5μg/mL、10μg/mL;1μg/mL、2.5μg/mL、5μg/mL的TCDCA均能显著或极显著提高细胞内cAMP含量(P<0.05或P<0.01),对cGMP含量均没有显著影响。说明TC-DCA能够显著提高正常和免疫抑制小鼠血清中和正常腹腔巨噬细胞内cAMP含量。     

Effects of initial and extended exposure to an endophyte-infected tall fescue seed diet on faecal and urinary excretion of ergovaline and lysergic acid in mature geldings

Abstract

AIM: To determine the amount of ergovaline and lysergic acid retained or excreted by geldings fed endophyte-infected seed containing known concentrations of these alkaloids, and the effects of exposure time on clinical expression of toxicosis.

METHODS: Mature geldings (n=10) received diets containing either endophyte-free (E-) or endophyte-infected (E+) tall fescue seed during three experimental phases. The first phase (Days ?14 to ?1) was an adaptation phase, to allow all horses to adapt to a diet containing E- tall fescue seed. The second (Days 0 to 3) was the initial exposure phase to E+ tall fescue seed, used for the delivery of ergovaline and lysergic acid at 0.5 and 0.3 mg/kg of diet, respectively, to test the initial effects of exposure on routes and amounts of elimination of alkaloid. During this phase, half the geldings were exposed to an E+ diet while the rest served as controls by remaining on the E- diet. Once assigned to treatments, geldings remained on the same diet through the third phase (Days 4 to 21), which served as the extended exposure phase. Total outputs of faeces and urine were collected within each phase, to determine retention of ergovaline and lysergic acid and nutrient digestibility. Serum was collected weekly and analysed for activities of enzymes and concentrations of prolactin. Bodyweights (BW) and rectal temperatures were recorded weekly.

RESULTS: BW, rectal temperature, enzyme activities and concentrations of prolactin in serum, and nutrient digestibility were not affected by treatment. Total intake of ergovaline by geldings on the E+ diet was 3.5 and 3.6 (SE 0.20) mg/day, and 2.1 and 2.3 (SE 0.11) mg/day were not accounted for in initial and extended phases, respectively. Lysergic acid was excreted in the urine (4.0 and 4.9 (SE 0.97) mg/day) and faeces (2.5 and 2.7 (SE 0.35) mg/day) at greater amounts than that consumed (2.0 and 1.9 (SE 0.09) mg/day) during the initial and extended exposure phases, respectively. Animals exposed to E+ seed for a period of 20 days appeared to excrete more (1.5 vs 1.2 mg/day; SE 0.08; p=0.03) ergovaline in the faeces than those exposed for only 4 days.

CONCLUSIONS: Exposure time to the ergot alkaloids had a limited effect on the route of elimination or the amounts of ergovaline or lysergic acid excreted by horses. The primary alkaloid excreted was lysergic acid, and urine was the major route of elimination. These data will aid future research to improve animals′ tolerance to toxic endophyte-infected tall fescue.     

Effects of maternal treatment with β‐hydroxy‐β‐metylbutyrate and 2‐oxoglutaric acid on femur development in offspring of minks of the standard dark brown type

The aim of the study was to evaluate the effect of the diet, mother type and sex of the offspring on the mechanical and geometric parameters of long bones as well as bone tissue density in minks. Primiparous and multiparous dams were supplemented with β‐hydroxy β‐methylbutyrate (a metabolite of leucine, at the daily dosage of 0.02 g/kg of body weight) and/or 2‐oxoglutaric acid (a precursor of glutamine, at the daily dosage of 0.4 g/kg of body weight) during gestation. The diet did not influence bone tissue density and the length of the humerus. An increase in the length of the femur was noted in male offspring delivered by multiparous dams. The diet resulted in an increase in the weight of the humerus in males from multiparous dams and a decrease in offspring from primiparous dams. Heavier femora were noted in male offspring delivered by both types of dams. The maximum elastic strength of the humerus was higher in the offspring delivered by multiparous than primiparous dams, irrespective of the offspring sex. The diet resulted in reduction in the ultimate strength of the femur in the male offspring delivered by primiparous dams. Only females born by multiparous dams, irrespective of the diet, showed a significant increase in the cross‐sectional area of the humerus, while a significant decline was noted in males delivered by multiparous dams and in all the offspring delivered by primiparous dams. An increase in the cross‐sectional area of the femur was noted in the offspring delivered by multiparous dams, while reduction was observed in the offspring delivered by primiparous dams. These results have shown for the first time that the presence of β‐hydroxy‐β‐methylbutyrate or 2‐oxoglutaric acid in the diet of pregnant primiparous or multiparous dams unambiguously affects the geometry and mechanical properties of offspring's long bones.