Expression Of MSTN Research Articles

252 Use of Agomir and Antagomir Technologies to Alter Mirna Expression and Muscle Hypertrophy in Intrauterine Growth Restricted Lambs

Abstract microRNAs (miRNA) are present in skeletal muscle and play important roles in regulating gene expression. Previous research identified miR-22-3p and miR-127 as differentially regulated during muscle hypertrophy and in vitro experiments found that antagomir-22-3p and mimic-127 enhanced satellite cell proliferation. The objective of this study was to test in vivo intramuscular injection of agomiR-127 or antagomir-22-3p in the longissimus muscle (LM) on miRNA and target mRNA expression in intrauterine growth restricted lambs. Pregnant ewes (n = 18) with twins were nutrient restricted (60%) from gestational d 85 to parturition. On d 2 of age, lambs were randomly selected and assigned to one of two miRNA treatments, 1) agomiR-127 (AGO127, 100 nM, n = 9) to assess gain of function or 2) antagomiR-22-3p (ANT22, 500 nM, n = 9) to assess loss of function. AgomiR and antagomiR technologies are chemically modified miRNA mimics or inhibitors that do not require transfection for in vivo use. AgomiR-127 or antagomir-22-3p were reconstituted in phosphate buffered saline (PBS) and injected into the center of the LM on the left side every 3-d starting at the 10th rib and moving posterior by 1.27 cm at each injection for a total of 7 injections. A sham control treatment (SHAM127 or SHAM22) of PBS was administered following the same protocol in the right LM to serve as the in-animal control. Lambs were harvested 4 d after the last injection and samples were collected from the injection region of each LM for miRNA and mRNA expression, histology, and proteomic analyses. Data were analyzed using paired t-tests to compare each miRNA treatment to its SHAM within animal. AGO127 up-regulated (P = 0.0071) miR-127 expression compared with SHAM127. mRNA expression of PAX7 and MSTN were up-regulated (P < 0.05) and IGFBP2 expression was down-regulated (P < 0.05) for AGO127 compared with SHAM127. Both protein and DNA content of AGO127 were increased (P < 0.05) but the ratio of protein to DNA did not change (P > 0.05). Proteomic analyses found 11 proteins that were differentially expressed for AGO127 compared with SHAM127. ANT22 down-regulated (P = 0.0024) miR-22-3p expression from SHAM22. Expression of predicted mRNA targets of miR-22-3p (ACVR2a, ACVR2b, SIRT1), myosin heavy chain isoforms (MyHCI, MyHCIIa, MyHCIIx), and other myogenic genes (MAPK6, IGF1, MyoG) were also altered (P < 0.05) in the LM compared with SHAM22. DNA content and the protein to DNA ratio was greater (P < 0.05) in ANT22 than SHAM22. Proteomic analyses identified nine proteins that were differentially expressed (P < 0.05) for ANT22. The direct injection of agomiR and antagomir technologies in the LM up- and down-regulated expression, respectively, for the miRNA of interest, which altered mRNA expression of predicted targets, protein abundance and muscle fiber type.

Overexpression of miR-29ab1 Cluster Results in Excessive Muscle Growth in 1-Month-old Mice by Inhibiting Mstn

Skeletal muscle mass is closely related to strength and health. Multiple genes and signaling pathways are involved in the regulation of skeletal muscle hypertrophy. miR-29 can participate in various processes of skeletal muscle development through different target genes. However, studies are needed on the function of miR-29 in skeletal muscle during mouse puberty. We used mice in which overexpression of miR-29ab1 cluster could be induced specifically within skeletal muscle, and investigated the effects of miR-29 overexpression on skeletal muscle at 1 month of age. We found that the overexpression of miR-29ab1 cluster in juvenile mice caused skeletal muscle mass and myofiber cross-sectional area to increase. The study on the mechanism of miR-29 inducing skeletal muscle hypertrophy had found that miR-29 achieved its function by inhibiting the expression of Mstn. At the same time, injured myofibers were present within miR-29ab1 cluster overexpressing skeletal muscle. The damage of skeletal muscle may be due to the inhibition of the type IV collagen by miR-29. These results indicate that although the overexpression of miR-29ab1 cluster can induce skeletal muscle hypertrophy in mouse juvenile, it simultaneously causes skeletal muscle damage.

Effects of dietary creatine levels on the growth, muscle energy metabolism and meat quality of spotted seabass (Lateolabrax maculatus) fed low-fishmeal diets

The study was performed to evaluate the effects of dietary creatine (CR) levels on the growth, muscle energy metabolism and meat quality of spotted seabass (Lateolabrax maculatus) fed low-fishmeal diets. The experimental diets were formulated with 15% fishmeal, and contained five creatine levels of 0.03%, 0.07%, 0.12%, 0.21% and 0.39%. Spotted seabass (initial body weight: 4.38 ± 0.06 g) were randomly allocated into 15 tanks (20 fish per tank) and fed twice daily for 8 weeks. With increasing dietary CR levels, the final body weight (FBW) and weight gain (WG) significantly increased, and the peak occurred in the 0.21% group. Second-order polynomial regression analysis showed that the optimum CR supplementation level based on WG was 0.25% for spotted seabass. With the increase in dietary CR levels, anaerobic glycolysis (the activities of lactic dehydrogenase and pyruvate kinase) in fish muscle was significantly reduced. The energy reserve (the content of ATP and activity of creatine kinase) was significantly increased to promote the pH value at 48 h postmortem with increasing CR levels. Water holding capacity increased as dietary CR levels increasing from 0.03% to 0.39%. The mRNA expression of myog, myod, myf5, mef2c, mstn, capn1 and capn2 was upregulated, but the mRNA expression of cast was downregulated with increasing CR levels from 0.03% to 0.39%. In conclusion, dietary CR supplementation promoted the growth performance of spotted seabass fed low-fishmeal diets, and the optimum creatine level was 0.25%. Dietary CR supplementation increased energy reserve and deceased anaerobic glycolysis at 48 h postmortem and enhanced meat quality.

Development of breast muscle parameters, glycogen reserves, and myogenic gene expression in goslings during pre- and post-hatching periods.

This study aimed to better understand the development patterns of breast muscle and glycogen reserves in goslings during pre- and post-hatching periods. The timepoints for sampling were embryonic days 23 and 27 of hatching and days 1, 4, and 7 post hatching. We found that the body weight of goslings increased with age. The small intestine developed with age and remained reasonably constant on day 4 post hatching. The breast muscle development decreased with age and stayed relatively stable on day 1 post hatching. The diameter of myofiber increased prior to hatching and then decreased while hatching. The development patterns of breast muscle glycogen reserves were similar to the diameter of myofiber. In contrast, the contents of liver glycogen began to decrease before hatching and then increased rapidly after hatching. Moreover, the expression of Myf-5 increased with age. The expression of MSTN was maintained at high levels prior to hatching, dropped immediately after hatching, and then gradually increased with age. Additionally, we also observed that the glycogen content in the breast muscle was positively correlated with the diameter of the myofiber. The liver glycogen content was positively correlated to the relative weight of the breast muscle, the diameter of the myofiber, and the breast muscle glycogen content. The development pattern of the myofiber was synchronized with the change in the MSTN/Myf-5 ratio. This study provided a profile to understand the development patterns of breast muscle, glycogen reserves, and myogenic gene expression in goslings, which was beneficial to understanding the characteristics of energy reserves during the early life of goslings.

Resistance Training Prevents Muscle Atrophy In Diabetic Rats Via MSTN Pathway

Type 1 diabetes mellitus (T1DM) induces serious skeletal muscle atrophy. resistance training is one of the effective ways to improve muscle atrophy. However, the mechanisms underlying exercise preventing muscle atrophy are still not clear. PURPOSE: To explore the influence of resistance training on muscle atrophy of type1 diabetes rats. METHODS: Fifty male Sprague-Dawley rats (8 weeks, 200-240 g) were randomly assigned to either the normal control group (NC = 8) or the T1DM model group (T1DM, n = 42). T1DM was induced by a single intraperitoneal injection of streptozotocin (STZ) at 60 mg/kg. Once T1DM was induced, the diabetic rats were randomly allocated into three groups: sham-treated diabetic control rats (DC + Sham, DC, n = 8), T1DM rats treated with an insulin injection (DC + INS, DI, n = 8), and treated with resistance training (DC + Training, DT, n = 8). The body weight and muscle strength were measured after the resistance training. HE staining of rat gastrocnemius test morphological changes in muscle fiber cross-sectional area. The protein levels and gene expression of MSTN, Akt, and FoxO1 were measured by Western Blot and Quantitative Real-time PCR. RESULTS: The body weights of NC continued to be remarkably higher than those in the other three diabetic groups during the whole experimental period (P < 0.01). After 6 weeks of training, the body weight (295.40 g ± 20.44 vs. 212.79 g ± 13.26, P < 0.01) and average peak force (9.54 N ± 1.57 vs. 7.85 N ± 1.69, P < 0.01) of DT were significantly increased compared with the DC. The muscle fiber cross-sectional area in the DT significantly increased compared with the DC rats (23729.87 μm2 ± 774.69 vs. 11726.46 μm2 ± 755.66, P < 0.01). DT significantly decreased the mRNA expression of MSTN (1.51 ± 0.22 vs. 2.62 ± 0.26, P < 0.01) and FoxO1(1.37 ± 0.12 vs. 2.26 ± 0.19, P < 0.01) compared with the DC group, as were in protein expression of MSTN (1.66 ± 0.02 vs. 2.09 ± 0.08, P < 0.01), and FoxO1(0.76 ± 0.02 vs. 0.92 ± 0.11, P < 0.05). The mRNA expression of Akt (0.47 ± 0.17 vs. 0.03 ± 0.01, P < 0.01) were increased in the DT, as were the protein expression of Akt (2.83 ± 0.22 vs. 1.64 ± 0.08, P < 0.01). CONCLUSION: These results indicate that 6 weeks of resistance training improved muscle atrophy induced by type 1 diabetes, and the MSTN/Akt/FoxO1 signaling pathway may play a role in this improvement.

Mstn knockdown promotes intramuscular fatty acid metabolism by β oxidation via the up-regulation of Cpt1b

Myostatin (Mstn) is known as growth/differentiation factor-8 (GDF-8). Knockout or knockdown of Mstn gene promotes muscle development and reduces fat content. Here we prepared Mstn knockdown mice by RNA interference, then the morphology of the skeletal muscle, the content of triglyceride (TG), the content and composition of fatty acids in the skeletal muscle were detected. The expression of Mstn reduced in muscle of Mstn knockdown mice compared to the controls. The cross sectional areas of the skeletal muscle myofibers were significantly larger while the content of TG was less than that of the controls, and the ratios of n-3/n-6 and unsat/sat in the knockdown mice increased significantly. Subsequently, we detected the expression of genes associated with fatty acid metabolism. The expression of the genes associated with lipolysis and fatty acid transportation were up-regulated, while the genes associated with fatty acid synthesis were down-regulated. Of these genes, the up-regulation of a gene associated with β oxidation, Cpt1b, was up-regulated remarkably. We further detected the enzyme activity of CPT1 in skeletal muscle and obtained the same results with gene expression. Moreover, chromatin immunoprecipitation assay was performed and we found that SMAD3, a transcription factor downstream of Mstn, directly binds to the promoter of Cpt1b gene. These results showed that knockdown of Mstn up-regulated the expression of Cpt1b through the binding of SMAD3 to the promoter of Cpt1b, then promoted the β oxidation metabolism of intramuscular fatty acids.

Dysregulated myokines and signaling pathways in skeletal muscle dysfunction in a cigarette smoke-induced model of chronic obstructive pulmonary disease.

Skeletal muscle dysfunction is an important extrapulmonary comorbidity of chronic obstructive pulmonary disease (COPD). Muscle-derived cytokines (myokines) play important roles in skeletal muscle growth and function, but their contributions to skeletal muscle dysfunction in COPD have not been fully understood. In the current study, by using a well-established mouse model of COPD with skeletal muscle dysfunction, we found that the expressions of Fndc5 (fibronectin type III domain-containing protein 5, the precursor of irisin) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) were decreased, while myostatin (Mstn), phosphorylated extracellular regulated kinase (p-Erk1/2), and p-Smad3 expressions were upregulated in skeletal muscles from cigarette smoke-exposed mice and in cigarette smoke extract (CSE)-stimulated C2C12 myotubes. Treatment with Smad3 or Erk1/2 inhibitors partially restored the expression of Fndc5 in CSE-stimulated C2C12 myotubes. Taken together, CSE exposure, by upregulation of p-Erk1/2, promoted the expression of Mstn, which further inhibited Fndc5 expression by the p-Smad3/PGC-1α pathway, revealing a novel regulating mechanism of myokines in the pathogenesis of skeletal muscle comorbidities of COPD.

Differential expression of MSTN, IGF2BP1, and FABP2 across different embryonic ages and sexes in white Muscovy ducks

To explore the effects of growth-related genes in both sexes and at different growth and development stages, male and female white Muscovy ducks at embryonic day E13, E17, E21, E25 and E29 were assessed in this study. RT-qPCR was used to determine the mRNA transcription levels of selected growth-related genes in the leg muscles of Muscovy ducks of both sexes and at different growth and developmental stages. MSTN, IGF2BP1 and FABP2 mRNAs were expressed in the leg muscles of male and female Muscovy ducks, but with different expression patterns. The MSTN and IGF2BP1 mRNA expression patterns were wavelike. MSTN mRNA expression was elevated at E13, increased at E17, decreased rapidly to the lowest level at E21, increased again at E25, and then decreased. IGF2BP1 mRNA expression was elevated at E13, increased at E17, decreased rapidly at E21, decreased rapidly to the lowest level at E25, and increased at E29. The expression trend of FABP2 mRNA was approximately “⊥” shape; the expression was the lowest at E13, increased slowly from E17 to E25, and increased extremely significantly at E29. In addition, the expression of MSTN in male Muscovy ducks was significantly higher than that in female ducks at E25 (P < 0.05). The expression of IGF2BP1 in male Muscovy ducks was extremely significantly higher than that in female ducks at E17 (P < 0.01). However, the expression of FABP2 in female Muscovy ducks was extremely significantly higher than that in male Muscovy ducks at E21 and E29 (P < 0.01). In conclusion, the mRNA expression of MSTN, IGF2BP1 and FABP2 in white Muscovy ducks is gestational age specific and sex specific. The differential gene expression patterns observed in this study provide a basis for understanding the physiological changes in white Muscovy ducks at different embryonic ages and in both sexes, supplementing the existing research on duck embryo muscle development. In addition, the findings provide a new framework for further discussion of poultry breeding.

Dietary Alaska Pollack Protein Induces Acute and Sustainable Skeletal Muscle Hypertrophy in Rats

Our previous studies suggested that Alaska pollack protein (APP) intake increases skeletal muscle mass and that it may cause a slow-to-fast shift in muscle fiber type in rats fed a high-fat diet after 56 days of feeding. In this study, we explored whether dietary APP induces acute and sustainable skeletal muscle hypertrophy in rats fed a normal-fat diet. Male 5-week-old Sprague–Dawley rats were divided into four groups and fed a purified ingredient-based high-fat diet or a purified ingredient-based normal-fat diet with casein or APP, containing the same amount of crude protein. Dietary APP significantly increased gastrocnemius muscle mass (105~110%) after 2, 7 days of feeding, regardless of dietary fat content. Rats were separated into two groups and fed a normal-fat diet with casein or APP. Dietary APP significantly increased gastrocnemius muscle mass (110%) after 56 days of feeding. Dietary APP significantly increased the cross-sectional area of the gastrocnemius skeletal muscle and collagen-rich connective tissue after 7 days of feeding. It decreased the gene expression of Mstn /Myostatin, Trim63/MuRF1, and Fbxo32/atrogin-1, but not other gene expression, such as serum IGF-1 after 7 days of feeding. No differences were observed between casein and APP groups with respect to the percentage of Type I, Type IIA, and Type IIX or IIB fibers, as determined by myosin ATPase staining after 7 days of feeding. In the similar experiment, the puromycin-labeled peptides were not different between dietary casein and APP after 2 days of feeding. These results demonstrate that APP induces acute and sustainable skeletal muscle hypertrophy in rats, regardless of dietary fat content. Dietary APP, as a daily protein source, may be an approach for maintaining or increasing muscle mass.

Replacement of fishmeal by yellow mealworm meal on the growth performance, feed utilisation and quality of large yellow croaker

An 80-day feeding trial was conducted to evaluate the effects of yellow mealworm (Tenebrio molitor, TM) meal as substitute for dietary fishmeal on the growth performance, feed utilisation and flesh quality of large yellow croaker (initial body weight: 189.18±0.13 g). The control diet (TM0) was designed to contain 56% of fishmeal. Based on the TM0, graded levels of TM meal (15, 30, 45, 60, 75 and 100%, respectively) were used to replace fishmeal to formulate the other six experimental diets (TM15, TM30, TM45, TM60, TM75 and TM100), respectively. The results showed that the survival was not significantly affected by dietary TM meal levels (P&gt;0.05). Compared with control group, the final body weight, weight gain rate and protein efficiency ratio decreased significantly when the replacement level over 30%, while feed conversion ratio increased significantly as replacement level over 45% (P&lt;0.05). The total protein-bound amino acid content in muscle was significantly increased with the increase of dietary TM meal inclusion (P&lt;0.05). With replacement level increasing, the percentage of eicosapentaenoic acid (EPA) and Σn-3/Σn-6 poly-unsaturated fatty acids (PUFA) in muscle significantly decreased (P&lt;0.05). Meanwhile, the skin redness (a*) and yellowness (b*) values in the ventral and bottom of ventral regions showed a decreasing and increasing trend, respectively (P&lt;0.05). The TM100 group showed a higher myofibre diameter and lower myofibre density compared to the control group (P&lt;0.05). Total replacement of fishmeal with TM meal significantly down-regulated and up-regulated the expression of myf6 and mstn, respectively (P&lt;0.05). The contents of inosine-5′-monophosphate and total free amino acids were significantly decreased with the increase of TM meal inclusion (P&lt;0.05). In conclusion, TM meal can replace at least 30% of dietary fishmeal protein without negative effects on the growth, feed utilisation and flesh quality of large yellow croaker.

Effect of high-concentrate diets on mRNA expression of genes related to muscle fiber type and metabolism of psoas major muscle in goats.

In the process of modern breeding, high-concentrate diets are widely used to meet the high energy nutritional requirements of animals but change the form of access to energy and nutrients and the way the organism metabolizes them. Goat psoas major (PM) muscle is a hybrid skeletal muscle whose characteristics are important for the motility and meat quality of goats. However, there are few studies on the effects of high-concentrate diets on the muscle type and metabolic characteristics of PM in goats. In this study, two treatment groups were set up: high concentrate group (HC) and control group (C). The expression of genes related to muscle type and metabolism of the PM was examined by quantitative PCR. The results showed that high concentrate promoted the conversion of PM fibers from intermediate to slow type at the mRNA level, improved the absorption, transport, and oxidation of fat by PM, and upregulated the expression of calpain system. These changes may be regulated by the involvement of differential expression of MSTN, Myf-5, and IGF-2. These results suggest that high concentrate may exert a positive effect on skeletal muscle function, metabolism, and meat quality in goats by affecting the expression of muscle type and metabolism-related genes.

Decorin regulates myostatin and enhances proliferation and differentiation of embryonic myoblasts in Leizhou black duck

Skeletal muscle is one of the most important economic traits in the poultry industry whose development goes through several processes influenced by several candidate genes. This study explored the regulatory role of DCN on MSTN and the influence of these genes on the proliferation and differentiation of embryonic myoblasts in Leizhou black ducks. Embryonic myoblasts were transfected with over-expressing DCN, Si-DCN, and empty vector and cultured for 24h, 48h, and 72h of proliferation and the comparative expression of DCN and MSTN were measured. The results showed that cells transfected with the over-expression DCN had a significantly (P<0.05) higher expression of DCN mRNA than the normal group and the expression of MSTN mRNA showed a downward trend during the proliferation of myoblasts. DCN mRNA expression was lower in cells transfected with Si-DCN than the normal group in all stages of proliferation. While the expression of MSTN in the Si-DCN transfected group was higher than the normal group with a significant (P<0.05) difference at the 72h stage. DCN mRNA increased at the early stage of differentiation but decreased (P>0.05) from the 6th day to the 8th day of differentiation. The level of MSTN increased gradually during the differentiation process of myoblasts until it decreased significantly on the 8th day. These results show that DCN enhances the proliferation and differentiation of Leizhou black duck myoblasts and suppresses MSTN activity.

Molecular and Metabolic Mechanism of Low-Intensity Pulsed Ultrasound Improving Muscle Atrophy in Hindlimb Unloading Rats.

Low-intensity pulsed ultrasound (LIPUS) has been proved to promote the proliferation of myoblast C2C12. However, whether LIPUS can effectively prevent muscle atrophy has not been clarified, and if so, what is the possible mechanism. The aim of this study is to evaluate the effects of LIPUS on muscle atrophy in hindlimb unloading rats, and explore the mechanisms. The rats were randomly divided into four groups: normal control group (NC), hindlimb unloading group (UL), hindlimb unloading plus 30 mW/cm2 LIPUS irradiation group (UL + 30 mW/cm2), hindlimb unloading plus 80 mW/cm2 LIPUS irradiation group (UL + 80 mW/cm2). The tails of rats in hindlimb unloading group were suspended for 28 days. The rats in the LIPUS treated group were simultaneously irradiated with LIPUS on gastrocnemius muscle in both lower legs at the sound intensity of 30 mW/cm2 or 80 mW/cm2 for 20 min/d for 28 days. C2C12 cells were exposed to LIPUS at 30 or 80 mW/cm2 for 5 days. The results showed that LIPUS significantly promoted the proliferation and differentiation of myoblast C2C12, and prevented the decrease of cross-sectional area of muscle fiber and gastrocnemius mass in hindlimb unloading rats. LIPUS also significantly down regulated the expression of MSTN and its receptors ActRIIB, and up-regulated the expression of Akt and mTOR in gastrocnemius muscle of hindlimb unloading rats. In addition, three metabolic pathways (phenylalanine, tyrosine and tryptophan biosynthesis; alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism) were selected as important metabolic pathways for hindlimb unloading effect. However, LIPUS promoted the stability of alanine, aspartate and glutamate metabolism pathway. These results suggest that the key mechanism of LIPUS in preventing muscle atrophy induced by hindlimb unloading may be related to promoting protein synthesis through MSTN/Akt/mTOR signaling pathway and stabilizing alanine, aspartate and glutamate metabolism.

Vitellogenin 2 promotes muscle development and stimulates the browning of white fat.

Eggs are rich in nutrients and contain a lot of protein. Although eggs have proved to accelerate the growth of C2C12 cells, the regulatory and mechanism of fertilized egg yolk extract (FEYE) on skeletal muscle development and fat metabolism remains unclearly. The mice were treated with FEYE by gavage for 24 d, we found that FEYE can inhibit the expression of skeletal muscle atrophy genes such as MSTN and Murf-1, and up-regulate the expression levels of MYOD, MYOG and Irisin. In addition, the treatment of FEYE induced UCP1 and PGC1α high expression in WAT, thereby causing WAT browning reaction. In order to confirm the composition of FEYE, we performed protein full spectrum identification (LC MS/MS) analysis and found the most enriched component is vitellogenin 2 (VTG2). Therefore, we added the recombinant protein VTG2 to C2C12 cells and found that VTG2 promoted the proliferation and differentiation of C2C12 cells. After that, we further proved that VTG2 inhibited the expression of MSTN and improved the expression of MYOD and Irisin. Finally, the dual luciferase test proved that VTG2 directly inhibited the transcriptional activity of MSTN. Our results conclude that FEYE inhibits the expression of MSTN in muscle tissues by delivering VTG2, thereby promoting skeletal muscle development, and can also promote the expression level of FNDC5 in serum. Then, FNDC5 acts on the fat through the serum, stimulating the browning reaction of white adipocytes. Therefore, VTG2 can be used to stop muscle consumption, improve skeletal muscle aging, and prevent obesity.

Dietary lysine supplementation improves growth performance and skeletal muscle development in rabbits fed a low protein diet

The purpose of this study was to investigate the effects on growth of Lysine (Lys) supplementation in a low protein diet. We also investigated the gene or protein expression related to skeletal muscle development and intestinal amino acid transporters, and determined the major signalling associated with Lys-regulating skeletal muscle development. 1000healthy, weights averaging 938.6±6.54g weaned rabbits were randomly divided into five groups (five replicates in each group and 40 rabbits in each replicate). These groups consisted of the normal protein group (NP group, consuming a diet containing 16.27% protein), the low protein group (LP group, 14.15%-14.19% protein) and the LP group with an addition of 0.15%, 0.3% or 0.45% Lys. The trial included 7 d of pre-feeding and 28 d of exposure to the treatment. Compared with NP diet and LP diet, LP+0.3% Lys group improved growth performance (p<0.05), full-bore weight and half-bore weight of rabbits (p<0.05). The LP+0.3% Lys group also resulted in a decrease in the excretion of faecal nitrogen and urinary nitrogen (FN; UN; p<0.05), and an increase in nitrogen utilisation rate (NUR; p<0.05). LP diet increased the mRNA expression of MSTN and WWP1, and decreased the mRNA expression of IGF1 (p<0.05). LP diet decreased the protein expression of P-P70S6K1, P-4EBP1 and P-S6 (p<0.05). LP+0.3% Lys group attenuated the effects of LP diet on the expression of MSTN, WWP1, IGF1, P-P70S6K1, P-4EBP1 and P-S6 (p<0.05). LP+0.3% Lys group resulted in an increase in mRNA expression of MyoD and protein expression of P-mTOR relative to the NP and LP groups (p<0.05). In summary, the addition of Lys to a LP diet provides a theoretical basis for the popularisation and application of Lys in rabbit production.

Association of myostatin deficiency with collagen related disease-umbilical hernia and tippy toe standing in pigs.

Herein, we investigate the high incidence of umbilical hernia and tippy-toe standing and their underlying changes in gene expression and proliferation in myostatin knockout (MSTN-/-) pigs. Thirty-six male MSTN-/- pigs were generated by somatic cell nuclear transfer (SCNT). These pigs presented a considerably high incidence of tippy-toe standing and umbilical hernia (69.4% and 61.1%, respectively). The tendon to body weight ratio was significantly lower than wild-type pigs (0.202 ± 0.017 vs 0.250 ± 0.004, respectively). The crimp length of the MSTN-/- tendon was significantly longer than that of wild-type pigs. The expression of MSTN and the activin type IIB (ACVR2B) was detected in the tendon and linea alba of MSTN-/- pigs. MSTN treatment significantly increased the phosphorylation of Smad2/3 in both tendon and linea alba fibroblasts. Type I collagen (Col1A) and Scleraxis (Scx) expression levels in the tendon and linea alba of MSTN-/- pigs were significantly lower than those in wild-type in vivo, whereas and cyclin-dependent kinase inhibitor 1 (p21) expression levels were higher. Treatment of tendon and linea alba fibroblasts with recombinant MSTN increased Col1A and Scx and decreased p21 expression in vivo. Moreover, there was a significant increase in fibroblast proliferation after treatment. The results indicated that MSTN regulates collagen expression and proliferation in tendon and linea alba fibroblasts; thus, MSTN deficiency causes collagen-related pathological features in MSTN-/- pigs. Hence, MSTN could be used as a therapeutic target for treating UH and tendon abnormalities.

Intervention of re-feeding on growth performance, fatty acid composition and oxidative stress in the muscle of red swamp crayfish (Procambarus clarkii) subjected to short-term starvation

The red swamp crayfish (Procambarus clarkii) is widely cultivated and consumed for its tender meat. The quality of P. clarkii is increasingly deteriorating due to a possible shortage of feed nutrition, posing a significant threat to its sustainability. To avoid the phenomenon mentioned above and enrich the culture technology of P. clarkii, the aim of this study was to assess the effect of re-feeding on alleviating oxidative damage caused by short-term starvation, as well as to investigate the relationship between oxidative stress and meat quality and its molecular regulation mechanism. A total of 600 crayfish weighing about 20.11 g were randomly divided into 4 groups: S0F0 (the control group), S0F3 (0 days of starvation and 3 days of re-feeding), S3F0 (3 days of starvation and 0 days of re-feeding) and S3F3 (3 days of starvation and 3 days of re-feeding). The results showed that starvation slowed down the growth of P. clarkii and significantly decreased the saturated fatty acids (SFA) contents in the muscle (P < 0.05). Meanwhile, starvation-induced production of large amounts of reactive oxygen species (ROS) in muscle, disrupted the structure of biomolecules in muscle, allowing myofiber to be destroyed, the structural basis of muscle and indirectly leading to muscle damage of P. clarkii. After three-day re-feeding, the growth performance of crayfish resumed. Besides, re-feeding induced the Nrf2/Keap1 pathway in the muscle and increased the expression level of downstream antioxidant enzyme genes, improving the ability of scavenging oxidative free radicals. The supply of feed also up-regulated the expression of MEF2a and MEF2b with the expression of MSTN being down-regulated, accompanied by a recovery of the textural properties and myofiber characteristics. Furthermore, the fatty acid composition was optimized where n3PUFA and n6PUFA mainly were changed. In summary, the growth of crayfish could be improved by re-feeding after three-day starvation and the negative impacts of starvation on muscle quality could be reversed by three-day refeeding.

Immunological response of fallopian tube epithelial cells to spermatozoa through modulating cytokines and chemokines

BackgroundSpermatozoa interactions with fallopian tubes may influence fertilization. The purpose was to investigate cytokines, chemokines and growth factors expression from human fallopian tube epithelial cells (OE-E6/E7) exposed to spermatozoa. MethodsFresh semen samples were obtained from 10 healthy normozoospermic men. Sperms were prepared and co-cultured with OE-E6/E7. The cell line without spermatozoa was considered as the control group. Afterwards, Expression of 84 cytokines from OE-E6/E7 cell line in the presence and absence of spermatozoa were measured using PCR-array. Quantitative PCR was performed on seven genes to confirm the results of PCR-array analysis. Differentially expressed genes were subjected to www.geneontology.org and www.pantherdb.org to perform GO enrichment and panther pathway analysis. The concentration of IL-8, IL-10, IL-1B and BMP-4 in culture medium were analyzed by ELISA. ResultsSperm interaction with the epithelial cells resulted in a significant increase in expression of TGF-β2, BMP-4, IL-10, IL-9, and CD40LG markers. Moreover, expression of IL-16, IL-17F, SPP-1, CXCL-13, MSTN, IL-1A, IL-1B, IL-8, BMP-7, CSF-2, CSF-3, VEGF-A, OSM, LTA, TNF, TNFRSF11B, TNFSF11, CCL-11, CCL-20, CCL-24, CCL-3, CCL-8, CX3CL1 and CXCL-9 were considerably reduced in presence of spermatozoa. Panther pathway analysis discovered 3 pathways for upregulated genes including gonadotropin-releasing hormone receptor, TGF-beta and interleukin signaling pathways. Furthermore, 9 pathways were detected for down-regulated genes. Inflammation signaling pathway which is mediated by chemokine and cytokine contains the most number of genes. ConclusionThis study indicates that sperm modifies expression of cytokines, chemokines and growth factors from OE-E6/E7. Moreover, altered genes expression are toward higher survival chance of the spermatozoa.

Weight-bearing exercise prevents skeletal muscle atrophy in ovariectomized rats.

Skeletal muscle atrophy (SMA) is a dominant symptom induced by estrogen deficiency which can lead to severe health problems of postmenopausal women. Furthermore, estrogen deficiency has severely compromised the maintenance of muscle stem cells as well as impairs self-renewal and differentiation into muscle fibers. Resistance training is commonly considered as a positive and useful intervention in accelerating the rate of muscle growth. As one of the resistance training, whether the weight-bearing exercise can alleviate SMA induced by estrogen deficiency has not been investigated. The rats were divided into 3 groups randomly: sham group, ovariectomized (OVX) group, and weight-bearing exercise (WBE) therapeutic group. The weight that rats were loaded was 35% of their body weight, and the rats were trained by treadmill training (5° slope, 20 m/min, 30 min/day, 6 days/week) for 8 weeks. After training, the quality and strength of skeletal muscle of the WBE rats were improved; meanwhile, the cross-sectional areas of the skeletal muscle were also increased. Moreover, the WBE activated Akt significantly, upregulated the expression of mTOR, and downregulated the expression of MSTN and its receptor ActRIIB and FoxO1, respectively. The SMA phenomena of rats which induced by estrogen deficiency were prevented effectively via WBE, and the MSTN/Akt/mTOR and FoxO1 signaling pathway may be the predominant way in this improvement.

Effects of replacement of dietary rapeseed meal by distiller's dried grains with solubles (DDGS) on growth performance, muscle texture, health and expression of muscle-related genes in grass carp (Ctenopharyngodon idellus)

The objective of this study was to compare the biological value between dietary rapeseed meal (RSM) and maize distiller's dried grain with solubles (DDGS) in juvenile grass carp (initial body weight: 5.38 ± 0.18 g) through a 60 d feeding trial. A control diet containing 28% RSM and 4 experimental diets containing 10.0, 20.6, 30.9, and 41.1% DDGS to replace RSM were formulated. The results showed that dietary DDGS inclusion significantly affected the growth performance including final body weight, SGR, FR, and FE, which all showed a quadratic trend as DDGS level increased. The optimal dietary DDGS level was estimated as 28.2% and 32.1%, respectively, based on the quadratic models of SGR and FE. As dietary DDGS level increased, hepatosomatic index decreased linearly (P = 0.000), while condition factor decreased and then increased in a quadratic model (P = 0.020). The mesenteric fat index showed a trend opposite to condition factor responding to DDGS level. Serum ALT, AST, and triglyceride levels decreased linearly with increasing dietary DDGS. As DDGS inclusion level increased, collagen content in raw muscle increased linearly, while muscle texture including hardness, gumminess and chewiness decreased linearly (P = 0.000). Muscle fiber diameter linearly increased with DDGS level (P = 0.000), while fiber density decreased in a quadratic model (P = 0.008). Apparent digestibility coefficients (ADCs) of dry matter and energy decreased at higher DDGS inclusion level (30.9% or more) while ADC of protein increased first and then decreased. The relationship between dietary DDGS inclusion level and expression of fgf6a, myhc, mrf4, mstn, and myf5 were explained by quadratic regression models. fgf6b expression decreased with DDGS level. Overall, Dietary DDGS replacing RSM showed positive effects on growth performance, lipid metabolism and muscle collagen content, while negatively affected hardness of muscle.