Influence of nonylphenol exposure on basic growth, development, and thyroid tissue structure in F1 male rats
PEERJ
Authors: Wang, Lin; Xu, Jie; Zeng, Feng; Fu, Xiangjun; Xu, Weihong; Yu, Jie
Abstract
Objective: Environmental endocrine disruptors (EEDs) with a weak ability to mimic estrogen have been associated with thyroid dysfunction. However, little is known about the effect of nonylphenol (NP), a well-known EED, on thyroid structure. The present study evaluates whether gestational and lactational exposure to NP impacts growth and thyroid structure in F1 male rats. Methods: A total of 60 rats were gavaged with NP (25, 50, and 100 mg/kg), estradiol (E-2, 30 mu g/kg/day), and corn oil alone (vehicle control) from gestational day 6 to postnatal day (PND) 21. Serum thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone levels were detected by automated chemiluminescence immunoassay analyzer. The NP level in the thyroid was measured using high-performance liquid chromatography. The ultrastructure of follicular epithelial cells was examined using transmission electron microscopy. Histopathology was conducted using hematoxylin and eosin staining. Results: On PND 0, exposure to 50 and 100 mg/kg/day NP led to a significant decrease in the average litter size, litter weight and number of live pups per litter compared to the control group (P < 0.05). Dams exposed to NP during perinatal period demonstrated decreased serum levels of FT3 and FT4 in Fl male rats, when compared to the control group (P < 0.05). The NP level in the control group was 3.39 +/- 0.08 ng/mg, while NP levels in the low, middle, and high dose groups ranged from 5.20 to 11.00 ng/mg. Exposure caused a dose-related increase in NP level in the thyroid of male pups (P < 0.01). The thicknesses of the thyroid follicular epithelium were 2.06 +/- 0.37 mu m in the control group and 3.97 +/- 1.61 mu m in the high-dose group. The thickness of the thyroid follicular epithelium increased with an increase in treatment dose in a dose-dependent manner (P < 0.05). The sizes of the thyroid follicles were 1,405.53 +/- 866.62 mu m(2) in the control group and 317.49 +/- 231.15 mu m(2) in the high-dose group. With increasing NP dosages, animals showed a decreased size of the thyroid follicle (P < 0.01). Thyroid follicular cells of NP-treated rats showed mildly swollen mitochondria and dilated rough endoplasmic reticulum in the cytoplasm. Conclusion: Nonylphenol can cross the placental barrier and accumulate in the thyroid of F1 male rats. Gestational and lactational exposure to NP in dams impacted both development and growth of pups and damaged the ultrastructure of their thyroid tissue, which may further negatively influence normal thyroid function.
Quantum strong energy inequalities
PHYSICAL REVIEW D
Authors: Fewster, Christopher J.; Kontou, Eleni-Alexandra
Abstract
Quantum energy inequalities (QEIs) express restrictions on the extent to which weighted averages of the renormalized energy density can take negative expectation values within a quantum field theory. Here we derive, for the first time, QEIs for the effective energy density (EED) for the quantized nonminimally coupled massive scalar field. The EED is the quantity required to be non-negative in the strong energy condition (SEC), which is used as a hypothesis of the Hawking singularity theorem. Thus establishing such quantum strong energy inequalities (QSEIs) is a first step towards a singularity theorem for matter described by quantum field theory. More specifically, we derive difference QSEIs, in which the local average of the EED is normal-ordered relative to a reference state, and averaging occurs over both timelike geodesics and spacetime volumes. The resulting QSEIs turn out to depend on the state of interest. We analyze the state-dependence of these bounds in Minkowski spacetime for thermal (KMS) states, and show that the lower bounds grow more slowly in magnitude than the EED itself as the temperature increases. The lower bounds are therefore of lower energetic order than the EED, and qualify as nontrivial state-dependent QEIs.