Recombinant Bovine Growth Hormone-Induced Metabolic Remodelling Enhances Growth of Gilthead Sea-Bream (Sparus aurata): Insights from Stable Isotopes Composition and Proteomics

Growth hormone and insulin-like growth factors (GH/IGF axis) regulate somatic growth in mammals and fish, although their action on metabolism is not fully understood in the latter. An intraperitoneal injection of extended-release recombinant bovine growth hormone (rbGH, Posilac^®) was used in gilthead sea bream fingerlings and juveniles to analyse the metabolic response of liver and red and white muscles by enzymatic, isotopic and proteomic analyses. GH-induced lipolysis and glycogenolysis were reflected in liver composition, and metabolic and redox enzymes reported higher lipid use and lower protein oxidation. In white and red muscle reserves, rBGH increased glycogen while reducing lipid. The isotopic analysis of muscles showed a decrease in the recycling of proteins and a greater recycling of lipids and glycogen in the rBGH groups, which favoured a protein sparing effect. The protein synthesis capacity (RNA/protein) of white muscle increased, while cytochrome-c-oxidase (COX) protein expression decreased in rBGH group. Proteomic analysis of white muscle revealed only downregulation of 8 proteins, related to carbohydrate metabolic processes. The global results corroborated that GH acted by saving dietary proteins for muscle growth mainly by promoting the use of lipids as energy in the muscles of the gilthead sea bream. There was a fuel switch from carbohydrates to lipids with compensatory changes in antioxidant pathways that overall resulted in enhanced somatic growth.     

NO message from muscle.

The synthesis of the free radical gas nitric oxide (NO) is catalyzed by the enzyme NO synthase (NOS). NOS converts arginine and molecular oxygen to NO and citrulline in a reaction that requires NADPH, FAD, FMN, and tetrahydrobiopterin as cofactors. Three types of NOS have been identified by molecular cloning. The activity of the constitutively expressed neuronal NOS (nNOS) and endothelial NOS (eNOS) is Ca(2+)/calmodulin-dependent, whereas that the inducible NOS (iNOS) is Ca(2+)-insensitive. The predominant NOS isoform in skeletal muscle is nNOS. It is present at the sarcolemma of both extra- and intrafusal muscle fibers. An accentuated accumulation of nNOS is found in the endplate area. This strict sarcolemmal localization of nNOS is due its association with the dystrophin-glycoprotein complex, which is mediated by the syntrophins. The activity of nNOS in skeletal muscle is regulated by developmental, myogenic, and neurogenic influences. NO exerts several distinct effects on various aspects of skeletal muscle function, such as excitation-contraction coupling, mitochondrial energy production, glucose metabolism, and autoregulation of blood flow. Inside the striated muscle fibers, NO interacts directly with several classes of proteins, such as soluble guanylate cyclase, ryanodine receptor, sarcoplasmic reticulum Ca(2+)-ATPase, glyceraldehyde-3-phosphate dehydrogenase, and mitochondrial respiratory chain complexes, as well as radical oxygen species. In addition, NO produced and released by contracting muscle fibers diffuses to nearby arterioles where it acts to inhibit reflex sympathetic vasoconstriction.     

Phospholipids: Identification and Implication in Muscle Pathophysiology

Phospholipids (PLs) are amphiphilic molecules that were essential for life to become cellular. PLs have not only a key role in compartmentation as they are the main components of membrane, but they are also involved in cell signaling, cell metabolism, and even cell pathophysiology. Considered for a long time to simply be structural elements of membranes, phospholipids are increasingly being viewed as sensors of their environment and regulators of many metabolic processes. After presenting their main characteristics, we expose the increasing methods of PL detection and identification that help to understand their key role in life processes. Interest and importance of PL homeostasis is growing as pathogenic variants in genes involved in PL biosynthesis and/or remodeling are linked to human diseases. We here review diseases that involve deregulation of PL homeostasis and present a predominantly muscular phenotype.     

Bi‐Layered Tubular Microfiber Scaffolds as Functional Templates for Engineering Human Intestinal Smooth Muscle Tissue

Designing biomimetic scaffolds with in vivo–like microenvironments using biomaterials is an essential component of successful tissue engineering approaches. The intestinal smooth muscle layers exhibit a complex tubular structure consisting of two concentric muscle layers in which the inner circular layer is orthogonally oriented to the outer longitudinal layer. Here, a 3D bi‐layered tubular scaffold is presented based on flexible, mechanically robust, and well aligned silk protein microfibers to mimic the native human intestinal smooth muscle structure. The scaffolds are seeded with primary human intestinal smooth muscle cells to replicate intestinal muscle tissues in vitro. Characterization of the tissue constructs reveals good biocompatibility and support for cell alignment and elongation in the different scaffold layers to enhance cell differentiation and functions. Furthermore, the engineered smooth muscle constructs support oriented neurite outgrowth, a requisite step to achieve functional innervation. These results suggest these microfiber scaffolds as functional templates for in vitro regeneration of human intestinal smooth muscle systems. The scaffolding provides a crucial step toward engineering functional human intestinal tissue in vitro, as well as engineering other types of smooth muscles in terms of their similar phenotypes. Such utility may lead to a better understanding of smooth muscle associated diseases and treatments.     

野百合碱诱导实验性肺动脉高压病理形态观察

目的：30只Wistar大鼠一次性腹腔注射野百合碱（monocrotaline,MCT)(60mg/kg体重），建立肺心病模型，观察野百合碱诱导肺动脉高压的机理。方法：利用注射野百合碱方法建立肺动脉高压的动物模型，通过光学显微镜及电子显微镜观察野百合碱对肺动脉血管内皮细胞的损伤，和导致肺动脉血管平滑肌增生及右心室的变化，并分析病变之间的关系。结果：野百合碱注射可使肺动脉血管内皮细胞损伤，并诱导肺动脉血管壁的重建，特别是平滑肌明显增生，右心室肥厚。     

水产品肌肉组织微观结构变化及其检测方法研究进展

水产品营养丰富、味道鲜美,深受消费者喜爱,其肌肉品质一直备受关注。肌肉品质可以通过肌肉组织微观结构进行判断,微观结构也常作为评价水产品肌肉品质的关键指标。本文综述水产品在原料、贮藏、加工和流通等多个阶段组织微观结构的变化过程,总结多种检测方法的技术特征及其在水产品肌肉组织微观结构中的适用范围,阐述肌肉组织微观结构与品质理化指标的关系,旨在为今后进一步完善水产品品质评价及调控体系提供参考。     

超临界CO2法提取乳木果油工艺优化及对大鼠抗氧化能力的影响

采用响应面优化超临界CO2法提取乳木果油的工艺,并研究其对大鼠抗氧化能力的影响。考察了单因素萃取压力、萃取时间、萃取温度对乳木果油得率的影响。结果表明：萃取压力为31MPa、萃取温度为39℃、萃取时间为165 min,得出乳木果油的平均得率为46.75%,与预测值较为吻合。同时运动大鼠试验表明,试验中研究了各组大鼠骨骼肌中的SOD、CAT、GSH-Px、MDA、.OH水平,得出灌胃乳木果油的大鼠SOD、CAT、GSH-Px水平明显提高,MDA、.OH水平明显降低,并且与剂量呈量效关系,说明乳木果油具有良好的抗氧化能力,可以有效降低大鼠力竭运动之后产生大量自由基对其骨骼肌造成的损伤,从而提高了大鼠的抗氧化能力。     

Maternal Undernutrition Modulates Neonatal Rat Cerebrovascular Structure,Function, and Vulnerability to Mild Hypoxic-Ischemic Injury via Corticosteroid-Dependent and -Independent Mechanisms

The present study explored the hypothesis that an adverse intrauterine environment caused by maternal undernutrition (MUN) acted through corticosteroid-dependent and -independent mechanisms to program lasting functional changes in the neonatal cerebrovasculature and vulnerability to mild hypoxic-ischemic (HI) injury. From day 10 of gestation until term, MUN and MUN-metyrapone (MUN-MET) group rats consumed a diet restricted to 50% of calories consumed by a pair-fed control; and on gestational day 11 through term, MUN-MET groups received drinking water containing MET (0.5 mg/mL), a corticosteroid synthesis inhibitor. P9/P10 pups underwent unilateral carotid ligation followed 24 h later by 1.5 h exposure to 8% oxygen (HI treatment). An ELISA quantified MUN-, MET-, and HI-induced changes in circulating levels of corticosterone. In P11/P12 pups, MUN programming promoted contractile differentiation in cerebrovascular smooth muscle as determined by confocal microscopy, modulated calcium-dependent contractility as revealed by cerebral artery myography, enhanced vasogenic edema formation as indicated by T2 MRI, and worsened neurobehavior MUN unmasked HI-induced improvements in open-field locomotion and in edema resolution, alterations in calcium-dependent contractility and promotion of contractile differentiation. Overall, MUN imposed multiple interdependent effects on cerebrovascular smooth muscle differentiation, contractility, edema formation, flow-metabolism coupling and neurobehavior through pathways that both required, and were independent of, gestational corticosteroids. In light of growing global patterns of food insecurity, the present study emphasizes that infants born from undernourished mothers may experience greater risk for developing neonatal cerebral edema and sensorimotor impairments possibly through programmed changes in neonatal cerebrovascular function.     

Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (Piaractus mesopotamicus) Juveniles: In Vivo and In Vitro Studies

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu (Piaractus mesopotamicus) following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.