Avaliação termográfica do desenvolvimento mamário de búfalas e sua regulação endócrina em distintos estágios fisiológicos / Thermographic evaluation of the mammary development of buffaloes and their endocrine regulation in different physiological stages

O conhecimento do desenvolvimento mamário de um rebanho leiteiro é fundamental, pois relaciona-se à eficiência produtiva. Objetivou-se avaliar a associação dos parâmetros térmicos mamários com concentrações hormonais de búfalas em distintos estágios fisiológicos. Foram utilizadas 24 búfalas mestiças Murrah, em quatro grupos (n= 6): grupo 1 (bezerras), grupo 2 (novilhas), grupo 3 (gestantes) e grupo 4 (lactantes). A cada 28 dias, durante 4 meses, realizaram-se exames de termografia digital por infravermelho para verificar temperatura superficial dos corpos mamários craniais (CMCr) e caudais (CMC), das cisternas craniais (CGMCr) e caudais (CGMC) e tetas craniais (TGMCr) e caudais (TGMC). Foi aferida temperatura retal (TR) e colhido sangue para mensuração das concentrações plasmáticas do fator semelhante a insulina tipo-I, insulina (INS), hormônio do crescimento (GH), progesterona (P4) e estradiol. Grupos 1 e 2 apresentaram correlação de TR com CGMCr. No grupo 3, TR correlacionou-se com TGMCr, TGMC e concentrações plasmáticas de P4. No grupo 4, houve correlação de TR com CGMC, TGMCr e concentrações plasmáticas de INS e GH, e de TGMC com concentrações plasmáticas de GH. Nos quatro grupos, CGMCr correlacionou-se com CMCr e TGMCr, semelhantemente ao observado na porção caudal. Variações térmicas mamárias refletiram alterações fisiológicas aguardadas nos períodos avaliados.(AU)

The knowledge of the mammary development of a dairy herd is key, since it is related to its productive efficiency. The objective of this study was to evaluate the association of mammary thermal parameters with hormonal concentrations of buffaloes at different physiological stages. Twenty-four Murrah crossbred buffaloes were used in four groups (n= 6): group 1 (calves), group 2 (heifers), group 3 (pregnant animals) and group 4 (lactating animals). Every 28 days, for 4 months, infrared digital thermography was performed to check the surface temperature of cranial (CrCM) and caudal (CCM) corpus mammae, cranial (CrC) and caudal (CC) cisterns and cranial (CrT) and caudal teats (CT). Rectal temperature (RT) was measured and blood was collected to measure plasma concentrations of insulin-like factor I, insulin (INS), growth hormone (GH), progesterone (P4) and estradiol. Groups 1 and 2 presented correlation of RT with CrC. In group 3, RT correlated with CrT, CT and plasma P4 concentrations. In group 4, there was correlation of RT with CC, CrT and plasma concentrations of INS and GH, and CT with plasma GH concentrations. In all four groups, CrC correlated with CrCM and CrT, similar to that observed in the caudal portion. The thermal changes in the mammary glands reflected the expected physiological changes in the evaluated periods.(AU)

Combining web-based tools for transparent evaluation of data for risk assessment: developmental effects of bisphenol A on the mammary gland as a case study.

Different tools have been developed that facilitate systematic and transparent evaluation and handling of toxicity data in the risk assessment process. The present paper sets out to explore the combined use of two web-based tools for study evaluation and identification of reliable data relevant to health risk assessment. For this purpose, a case study was performed using in vivo toxicity studies investigating low-dose effects of bisphenol A on mammary gland development. The reliability of the mammary gland studies was evaluated using the Science in Risk Assessment and Policy (SciRAP) criteria for toxicity studies. The Health Assessment Workspace Collaborative (HAWC) was used for characterizing and visualizing the mammary gland data in terms of type of effects investigated and reported, and the distribution of these effects within the dose interval. It was then investigated whether there was any relationship between study reliability and the type of effects reported and/or their distribution in the dose interval. The combination of the SciRAP and HAWC tools allowed for transparent evaluation and visualization of the studies investigating developmental effects of BPA on the mammary gland. The use of these tools showed that there were no apparent differences in the type of effects and their distribution in the dose interval between the five studies assessed as most reliable and the whole data set. Combining the SciRAP and HAWC tools was found to be a useful approach for evaluating in vivo toxicity studies and identifying reliable and sensitive information relevant to regulatory risk assessment of chemicals. Copyright © 2016 John Wiley & Sons, Ltd.

Quantitative Assessment of Mouse Mammary Gland Morphology Using Automated Digital Image Processing and TEB Detection.

The assessment of rodent mammary gland morphology is largely used to study the molecular mechanisms driving breast development and to analyze the impact of various endocrine disruptors with putative pathological implications. In this work, we propose a methodology relying on fully automated digital image analysis methods including image processing and quantification of the whole ductal tree and of the terminal end buds as well. It allows to accurately and objectively measure both growth parameters and fine morphological glandular structures. Mammary gland elongation was characterized by 2 parameters: the length and the epithelial area of the ductal tree. Ductal tree fine structures were characterized by: 1) branch end-point density, 2) branching density, and 3) branch length distribution. The proposed methodology was compared with quantification methods classically used in the literature. This procedure can be transposed to several software and thus largely used by scientists studying rodent mammary gland morphology.

Assessment of the proliferative capacity of the flavanones 8-prenylnaringenin, 6-(1.1-dimethylallyl)naringenin and naringenin in MCF-7 cells and the rat mammary gland.

8-Prenylnaringenin (8-PN) and naringenin (Nar) are phytoestrogens found in food items and nutritional supplements, while 6-(1.1-dimethylallyl)naringenin (6-DMAN) is a component of an African plant. Besides their assumed beneficial effects they may promote mammary and endometrial cancer. We therefore assessed their proliferative and estrogenic potential on the mammary gland in vitro and in vivo. In competitive estrogen receptor (ER) ligand binding assays 8-PN displayed a high relative binding affinity for both ERs with a preference for ERα and had the strongest mitotic effect on MCF-7 cells among the test substances. In a three day exposure in young adult ovariectomized female rats 15 mg/kg 8-PN had the highest capacity to increase the number of terminal end buds (TEB) in the mammary gland and stimulated expression of proliferation markers in epithelial ductal cells, followed by 6-DMAN and Nar, but overall their capacity to stimulate proliferation was weak in comparison to 17ß-Estradiol (E2).

Quantitative assessment of mammary gland development in female Long Evans rats following in utero exposure to atrazine.

In this study, we quantified the effects of in utero exposure to the herbicide atrazine on subsequent mammary gland development. Atrazine was administered to pregnant female Long Evans rats from gestation days 13-19 at doses of 0, 6.5, 50, or 100 mg/kg/day. A pair-fed control group was yoked to the high-dose atrazine-treated group. Litter size was standardized to 10 pups on postnatal day (PND) 4. Whole mounts of the left fourth mammary gland and histologic sections of the right fourth gland were obtained from a subgroup of offspring on PND1, 21, 33, on day of vaginal opening (VO), or around PND65 at diestrus. A blinded, quantitative analysis of key morphological features in mammary gland whole mounts (ductal elongation, ductal network area, epithelial area, terminal end bud [TEB] incidence, and epithelial density) as well as epithelial proliferation within different parenchymal structures was conducted. There was no effect of atrazine exposure on any of the measures of mammary gland development at the maternal dose of 6.5 mg/kg/day. On PND1, ductal elongation was increased by approximately 20% (p < 0.05) in the female offspring born to dams exposed to 50 and 100 mg/kg/day atrazine, coincident with decreased epithelial proliferation in the 100 mg/kg/day group at this age. These differences were not present on PND21, or thereafter. An increased incidence of TEB in the mammary glands from females that were born to both the pair-fed and 50 mg/kg/day-treated dams at the time of VO indicated that this response was a specific result of maternal caloric restriction. Collectively, these data indicate that maternal atrazine exposure has no long-term effects on mammary gland development in female offspring beyond a transitory response to high doses at PND1.

Effects of diet and bovine somatotropin on heifer growth and mammary development.

Forty Holstein heifers [body weight (BW) = 126 kg] were blocked by BW into groups of 4, and, within each block, heifers were randomly assigned to one of four treatments. Twenty heifers had ad libitum access to a diet formulated to produce a BW gain of 0.8 kg/d (control diet), and 20 heifers had ad libitum access to a diet formulated to produce a BW gain of 1.2 kg/d. (high diet). Half of the heifers fed each diet were injected daily with bovine somatotropin (bST; 25 micrograms/ kg of BW). The high diet increased daily BW gain as well as body condition score. Injection of bST also increased daily BW gain, but did not affect body condition score. The high diet reduced age at puberty by 58 d, but did not affect BW, withers height at puberty, or pelvic area at slaughter. Injection of bST had no effect on age at puberty, but increased BW, withers height at puberty, and pelvic area at slaughter. The high diet did not affect mammary parenchymal DNA, RNA, or the ratio of RNA to DNA. The injection of bST increased mammary parenchymal DNA, RNA, and the ratio of RNA to DNA. The high diet was more cost effective for rearing dairy heifers from 120 d of age to potential breeding size (> or = 363 kg of BW and postpubertal) than was the control diet. In conclusion, the high protein, high energy diet increased growth rate without detrimental effects on mammary development. Injection of bST increased BW, skeletal size, and mammary development.