Serum α‐1‐acid glycoprotein concentration in clinically healthy puppies and adult dogs and in dogs with various diseases

Background: α‐1‐acid glycoprotein (AGP) is an acute‐phase protein and a serum marker of inflammation and neoplasia in humans. AGP concentrations in diseased dogs and the potential effects of age, breed, and sex have not been elucidated. Objective: The purpose of this study was to examine differences in AGP concentration based on age, sex, and breed in a large population of clinically healthy dogs and to compare AGP concentrations in dogs with various diseases. Methods: Serum was obtained from clinically healthy puppies (n=74) and adults (n=172) of both sexes, and included mongrels (n=205) and Beagles (n=41). Serum also was obtained from 192 dogs with various diseases, including 8 with pyometra that were sampled before, and 1, 2, 3, and 10 days after surgery. AGP concentration was measured by single radial immunodiffusion. Statistical comparisons were made among age, sex, breed, and disease groups. Results: Serum AGP in healthy adult mongrels was 364±106 mg/L (reference interval, 152–576 mg/L). AGP was lowest in newborns (n=11, 122±54 mg/L) and gradually increased to adult levels by 3 months of age. Median AGP concentration was highest in dogs with parvovirus (n=17, 2100 mg/L), distemper (n=7, 1250 mg/L), and pyometra (n=18, 2480 mg/L) and was also significantly higher in dogs with acute filariasis, renal failure, urolithiasis, pancreatitis, hepatitis, trauma, hyperadrenocorticism, and immune‐mediated hemolytic anemia. Dogs with acute filariasis and acute hepatopathy had significantly higher AGP concentrations than dogs with chronic filariasis and chronic hepatopathy. Serum AGP concentration decreased gradually following surgery for pyometra but remained increased after 10 days (896±175 mg/L). Conclusions: Because of significantly lower AGP in puppies, the age of dogs should be considered when using AGP as a marker of disease. Serum AGP may be a useful marker of inflammatory disease in dogs and may help differentiate acute and chronic stages of disease.     

Effect of intake of linoleic acid and α‐linolenic acid levels on conversion into long‐chain polyunsaturated fatty acids in backfat and in intramuscular fat of growing pigs

A study was conducted to determine the effect of two levels of linoleic acid (LA) intake at either high or low α‐linolenic acid (ALA) intake on their conversion and subsequent deposition into long‐chain (20–22 C‐atoms) polyunsaturated fatty acids (LC PUFA) in muscle and backfat in growing pigs. In a 2 × 2 factorial arrangement, 32 gilts from 8 litters were assigned to one of four dietary treatments, varying in LA and ALA intakes. Low ALA and LA intakes were 0.15 and 1.31 g/(kg BW^0.75/day), respectively, and high ALA and LA intakes were 1.48 and 2.65 g/(kg BW^0.75/day) respectively. There was a close positive relation between intake of ALA and the concentration of ALA in backfat and in intramuscular fat. Dietary ALA did not affect the concentration of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but increased docosapentaenoic acid (DPA) in backfat. High ALA intake did not significantly affect DHA but significantly increased EPA, 20:3 n‐3 and DPA concentrations in intramuscular fat. The n‐3 LC PUFA proportion in backfat was increased from approximately 1–3%, which may be useful to enrich meat with these fatty acids. The effect of ALA intake on n‐3 LC PUFA was suppressed by LA intake. Dietary ALA suppressed the concentration of n‐6 LC PUFA in blood plasma by more than 50%. When compared at equal incremental dose, the inhibiting effect of ALA on blood arachidonic acid was stronger than the stimulating effect of LA as precursor.     

Utilization of stereoisomers from alpha‐tocopherol in livestock animals

Alpha‐tocopherol derived from natural source is a single stereoisomer (i.e. RRR‐α‐tocopherol), whereas synthetic α‐tocopherol consists of a mixture of eight stereoisomers, including RRR‐, RRS‐, RSR‐, RSS‐α‐tocopherol (the 2R isomers, R configuration at positions 2′ of the phytyl tail) and SRR‐, SSR‐, SRS‐ and SSS‐α‐tocopherol (the 2S isomers, S configuration at positions 2′ of the phytyl tail). R and S are assigned by the sequence‐rule procedure, i.e. the priorities of the substituents decrease in clockwise direction or anti‐clockwise direction at each chiral centre. Not all these stereoisomers are equally bio‐available, which can be explained by the differences in the rate of degradation, transportation and retention. Humans and livestock animals can only utilize the 2R forms, while the 2S forms have very low bio‐availability or basically are not bio‐available. The utilization of 2R forms differs between different animal species. For humans and livestock animals, RRR‐α‐tocopherol has the highest bio‐availability compared with other stereoisomers, while other 2R forms have lower bio‐availability compared with RRR‐α‐tocopherol. The relative bio‐availability of RRR‐ and all‐rac‐α‐tocopherol is related to animal species, ages of animals and assessment criteria. In general, recent literature studies have demonstrated that the relative bioavailability of RRR‐ and all‐rac‐α‐tocopherol is 2:1, differing from the commonly used conversion factor of 1.36:1. The latter was based on rat‐resorption‐gestation test. Most recent studies have shown that this conversion factor of 1.36:1 is not applicable to livestock animals and based on other metabolic functions. When IU is required to express vitamin E activity, new conversion factors need to be defined for livestock animals. Quantitative determination of bio‐availability of the individual α‐tocopherol stereoisomers will give a more detailed picture of the bioavailability of natural and synthetic vitamin E forms.     

Calming effect of orally administered γ‐aminobutyric acid in Shih Tzu dogs

The calming effects of γ‐aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non‐administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre‐administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P < 0.05) and walking (P < 0.05) tended to decrease compared to non‐administration. A significant depression in the urinary cortisol level was observed at 7 h after administration (P < 0.05). These results indicate that orally administrated GABA exerts calming effects on dogs as well as humans.     

Olive leaves (Olea europea L.) and α‐tocopheryl acetate as feed antioxidants for improving the oxidative stability of α‐linolenic acid‐enriched eggs

Ninety‐six brown Lohmann laying hens were equally assigned into four groups with six replicates. Hens within the control group were fed a corn–soybean‐based diet supplemented with 4% linseed oil. Two other groups were given the same diet further supplemented with 5 or 10 g ground olive leaves/kg feed, while the diet of the fourth group was further supplemented with 200 mg α‐tocopheryl acetate/kg. Supplementing diets with olive leaves had no effect on egg production, feed intake and egg traits. Eggs collected 28 days after feeding the experimental diets were analysed for lipid hydroperoxides and malondialdehyde (MDA) content, fatty acid profile, α‐tocopherol concentrations and susceptibility to iron‐induced lipid oxidation. Olive leaves were also analysed for total and individual phenolics, and total flavonoids, whereas their antioxidant capacity was determined using both the DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS (2,2‐azinobis3‐ethylbenzothiazoline‐6‐sulphonic acid) radical scavenging activity assays. Results showed that neither α‐tocopheryl acetate nor olive leaves supplementation exerted (p > 0.05) any effect on the fatty acid composition of n‐3 eggs. Supplementing the diet with 5 g olive leaves/kg had no (p > 0.05) effect on the hydroperoxide levels of n‐3 eggs, while supplementing with 10 g olive leaves/kg or 200 mg α‐tocopheryl acetate/kg, the lipid hydroperoxide levels were reduced (p ≤ 0.05) compared to control. However, although hydroperoxides were reduced, MDA, a secondary lipid oxidation product, was not affected (p > 0.05). Iron‐induced lipid oxidation increased MDA values in eggs from all groups, the increase being higher (p ≤ 0.05) in the control group and the group supplemented with 5 g olive leaves/kg. The group supplemented with 10 g olive leaves/kg presented MDA values lower (p ≤ 0.05) than the control but higher (p ≤ 0.05) than the α‐tocopheryl acetate group, which presented MDA concentrations lower (p ≤ 0.05) than all other experimental diets at all incubation time points.     

Relation between respiratory activity and sperm parameters in boar spermatozoa cryopreserved with alpha‐tocopherol and selected by Sephadex

Our aim was to evaluate the effect of Sephadex filtration on respiratory activity of porcine spermatozoa and its relation with quality and functional sperm parameters. Samples were evaluated regarding oxygen uptake and sperm parameters: motility, plasma and acrosome membrane integrity, capacitation and acrosome reaction induction in vitro, plasma membrane functionality, determined by the hypo‐osmotic swelling test (HOST), and lipid peroxidation assessed by thiobarbituric acid assay. Sephadex filtration improved all routine quality parameters (motility, plasma and acrosome membrane integrity) and functional parameters (HOST, in vitro capacitation and true acrosome reaction levels) and produced a significant decrease in cryocapacitation and lipid peroxidation. Oxygen uptake increased in Sephadex samples (41 ± 7%) respect to single washing. Oxygen addition of carbonyl‐cyanide‐m‐chlorophenylhydrazone (CCCP) confirmed mitochondrial coupling in washed and Sephadex samples; showing an increase of 2.6 and 4.2 times for oxygen consumption in single washing and Sephadex ones, respectively. The increase in oxygen uptake with succinate addition with respect to basal oxygen uptake was significantly lower in Sephadex samples (63 ± 25%) than in the washed ones (183 ± 35%). Sephadex samples showed higher mitochondrial activity measured by oxygen consumption and improved quality and functional parameters. Our study recommends this protocol due to the fact that this filtration method removes dead or damaged spermatozoa allowing to obtain cryopreserved boar spermatozoa with optimized fertilizing capacity.     

Expression analysis of an α‐1, 3‐galactosyltransferase,an enzyme that creates xenotransplantation‐related α–Gal epitope,in pig preimplantation embryos

α‐1,3‐Galactosyltransferase (α‐GalT), an enzyme creating Galα1‐3Gal (α‐Gal) epitope on the cell surface in some mammalian species such as pigs, is known to be a key factor that causes hyperacute rejection upon transplantation from pigs to humans. To establish the RNA interference‐based suppression of endogenous α‐GalT messenger RNA (mRNA) synthesis in porcine preimplantation embryos, we determined the suitable embryonic stage at which stage such approach is possible by using the semi‐quantitative RT‐PCR (qRT‐PCR) and the cytochemical method using a fluorescence‐labeled Bandeiraea simplicifolia Isolectin B₄ (BS‐I‐B₄). Staining with BS‐I‐B₄ demonstrated that α‐Gal epitope expression was first recognized at the 8‐cell stage, and increased up to the hatched blastocyst stage. Single embryo‐based qRT‐PCR also confirmed this pattern. These results indicate that creation of α‐Gal epitope is proceeded by de novo synthesis of α‐GalT mRNA in porcine preimplantation embryos with peaking at the blastocyst stage.     

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.     

Effect of increased feeding of dietary α‐linolenic acid by grazing on formation of the cis9,trans11–18:2 isoform of conjugated linoleic acid in bovine milk

Feeding systems such as grazing affect the fatty acid profile of bovine milk fat. In addition, milk fat is formed as the product of fatty acid metabolism in cow bodies before being secreted into milk. However, how grazing influences milk fatty acid profile through the metabolism has not been completely characterized. When fatty acid concentrations in Holstein milk were compared between grazing and non‐grazing periods, α‐linolenic acid was significantly higher in the grazing period than in the non‐grazing period. This could be explained with an increase in α‐linolenic acid feeding with grazing. α‐linolenic acid had a linear positive correlation with conjugated linoleic acid (9c,11t‐18:2) (CLA) and vaccenic acid (VA) during the grazing period, whereas CLA had higher correlation with linoleic acid rather than with α‐linolenic acid during the non‐grazing period. These data indicate that the high content of dietary α‐linolenic acid affects CLA and VA formation in milk of grazing periods via α‐linolenic acid metabolism into VA.     

Mitochondrial biogenesis and PGC‐1α gene expression in male broilers from ascites‐susceptible and ‐resistant lines

Ascites is a cardiovascular metabolic disease characterized by accumulation of fluid around the heart and in the abdominal cavity that eventually leads to death. This syndrome is the end‐point result of a series of metabolic incidents that are generally caused by impaired oxygen availability. Mitochondria are the major sites of oxygen consumption, therefore major contributors to oxidative stress. Genetic, metabolic and dietary factors can influence variations in mitochondrial biogenesis (mitochondrial size, number and mass) that might have an effect on oxygen consumption and reactive oxygen species production. This study evaluated the effect of genotype on PGC‐1α mRNA gene expression and mitochondrial biogenesis. These parameters were examined in male broiler chickens at 22 weeks of age from the SUS and RES lines divergently selected for ascites phenotype. From each line, five birds were sampled for right ventricle and breast muscle. Gene expression and mtDNA copy number were assessed by quantitative PCR. Results showed that birds from SUS had significantly higher PGC‐1α mRNA gene (p = .033) and mitochondrial DNA copy number (p = .038) in breast muscle. There was no difference in right ventricle PGC‐1α expression or mitochondrial DNA copy number between the two lines. These findings indicate that mitochondrial biogenesis and PGC‐1α mRNA gene expression differ between male broiler chickens from RES and SUS lines in a tissue‐specific manner.     

Expression of VEGFR and PDGFR‐α/‐β in 187 canine nasal carcinomas

Radiotherapy represents the standard of care for intranasal carcinomas. Responses to tyrosine kinase inhibitors (TKIs) have been reported but data on expression of target receptor tyrosine kinases (rTKs) is limited. This study characterizes the expression of vascular endothelial growth factor receptor (VEGFR), platelet‐derived growth factor receptor (PDGFR)‐α and PDGFR‐β in canine intranasal carcinomas. Histological samples from 187 dogs were retrieved. Immunohistochemistry was performed using commercially available antibodies. Expression of rTKs was classified into weak, moderate or intense and additionally recorded as cytoplasmic, membranous, cytoplasmic‐membranous, nuclear or stromal. VEGFR was expressed in 158 dogs with predominantly moderate expression (36.9%) and a cytoplasmic‐membranous expression pattern (70.9%). PDGFR‐α was detected in 133 with predominantly weak expression (57.9%) and cytoplasmic pattern (87.9%). PDGFR‐β was identified in 74 patients with a predominantly moderate expression (17.6%) and cytoplasmic expression pattern (63.5%). Co‐expression of rTKs was common. These results confirm expression of VEGFR, PDGFR‐α and PDGFR‐β in canine intranasal carcinomas and support the utility of TKIs.     

The influence of different doses of α-tocopherol and ascorbic acid on selected oxidative stress parameters in in vitro culture of leukocytes isolated from transported calves

The objective of the study was to assess in vitro the influence of various doses of two different antioxidants, α-tocopherol and ascorbic acid, on protective mechanisms against ROS in white blood cells obtained from calves exposed to transport, and to compare these results with those obtained from non-transported animals.The concentrations of lipid peroxidation products in leukocytes and in the retained medium were assessed by determining the level of ThioBarbituric Acid Reactive Substances (TBARS). Total antioxidant status in the leukocytes and the medium were estimated using a ferric-reducing ability of plasma (FRAP) assay. Leukocyte viability was determined using the trypan blue reduction test.The study demonstrated that after bovine leukocytes (WBC) were incubated in vitro with α-tocopherol and ascorbic acid, peroxidation intensity decreased and total antioxidant capacity increased. The results of the study reveal that these antioxidants in concentrations over 0.1 mg/ml have a major impact on free radical activity on bovine white blood cells and on cell viability during transport of animals.Based on this study, we suggest that incubation of the leukocytes with antioxidants decreases the oxidative stress development, which can be helpful in protection of the immunological cells during bovine respiratory disease.     

The long‐term effect of α‐ketoglutarate,given early in postnatal life,on both growth and various bone parameters in pigs

The long‐term effect of α‐ketoglutarate (AKG) given for 21–24 days post‐partum, on the skeleton of commercial pigs, was investigated. In experiment A, 12 pigs were given AKG [0.1 g/kg of body weight (b.w.) per day per os], while 12 controls were administered vehicle. At day 169, the left and right femur, humerus and sixth ribs were analysed for mechanical and geometrical properties and quantitative computed tomography. In experiment B, 32 piglets were divided equally into an AKG group (0.3 g/kg of b.w. per day) or a control group. Blood, taken at days 24 and 53 was analysed for plasma 17 β‐oestradiol. The main bone effect of AKG was to increase bone length in the sixth rib (7.3%, p < 0.01), ultimate strength (23%, p < 0.05), Young´s modulus (52%, p < 0.001) and maximum elastic strength (31%, p = 0.056) compared with controls. In both experiments, AKG preferentially increased the growth of female piglets, whilst for male piglets AKG had the opposite effect. In addition, AKG elevated plasma 17 β‐oestradiol levels compared to those of controls at the end of the period of treatment (20%, p = 0.002). It is concluded that AKG has long‐term effects on rib properties when given early in postnatal life whilst it elevates plasma 17 β‐oestradiol levels only so long as it is being administered.     

β‐hydroxy‐β‐methyl butyrate promotes leucine metabolism and improves muscle fibre composition in growing pigs

The aim of this study was to investigate the effects of excess leucine (Leu) vs. its metabolites α‐ketoisocaproate (KIC) and β‐hydroxy‐β‐methyl butyrate (HMB) on Leu metabolism, muscle fibre composition and muscle growth in growing pigs. Thirty‐two pigs with a similar initial weight (9.55 ± 0.19 kg) were fed 1 of 4 diets for 45 days: basal diet, basal diet + 1.25% L‐Leu, basal diet + 1.25% KIC‐Ca, basal diet + 0.62% HMB‐Ca. Results indicated that relative to the basal diet and HMB groups, Leu and KIC groups exhibited increased Leu concentrations and decreased concentrations of isoleucine, valine and EAAs in selected muscle (p < 0.05) and had lower mRNA levels of MyHC I and higher expression of MyHC IIx/IIb (p < 0.05), and there was no significant difference between the basal and HMB‐supplemented groups. Moreover, the mRNA expression levels of AMPKα and UCP3 were higher but the myostatin mRNA levels were lower in the soleus muscle of the HMB group than those from other groups (p < 0.05). These findings demonstrated that doubling dietary Leu content exerted growth‐depressing effects in growing pigs; dietary KIC supplementation induced muscular branched‐chain amino acid imbalance and promoted muscle toward a more glycolytic phenotype; while dietary HMB supplementation promoted the generation of more oxidative muscle types and increased muscle growth specially in oxidative skeletal muscle, and these effects of HMB might be associated with the AMPKα‐Sirt1‐PGC‐1α axis and mitochondrial biogenesis.     

The influence of sex and gonadectomy on hepatic and brain fatty acid composition,lipogenesis and β‐oxidation

The aim of this study was to investigate the influence of sex and castration of rats on liver and brain fatty acid profile and liver mRNA expression of genes involved in lipogenesis and β‐oxidation. Castration significantly increased body weight and liver index and decreased serum triglyceride content in the female rats. The fatty acid composition of the liver tissue was influenced by sex and castration. Male rats had higher content of C16:0, C18:1n7, C18:2n6 and C22:5n3, while female rats had higher content of C18:0, C20:4n6 and C22:6n3. Castration of male rats decreased differences caused by sex for C18:2n6, C20:4n6 and C22:6n3. Values for C16:1n7 were higher in the castrated male rats in comparison with all other groups. Liver phospholipids showed a distribution of fatty acids similar to the total lipids. Brain total lipids and phospholipids were not influenced by sex or castration. Castration increased ?6D gene expression in both the sexes, while ?5D and ?9D increased in females and males respectively. Gonadectomy increased expression of the FASN gene in the females and decreased CPT1 and ACOX1 gene expression in the liver tissue of male rats. The observed results of lipid peroxidation, measured by TBARS, were the lowest in the intact females in comparison with all other groups. In conclusion, sex strongly influences both SFA and PUFA in liver tissue, and castration decreases these differences only for PUFA. Castration also influences the expression of the genes involved in lipid metabolism differently in male and female rats, with an increase in lipogenic genes in female rats and a decrease in key genes for mitochondrial and peroxisomal β‐oxidation in male rats.     

Identification of apolipoprotein A‐I in the α‐globulin fraction of avian plasma

Background: Plasma protein electrophoresis is frequently used in birds as a tool for the diagnosis and monitoring of disease. Identification of proteins in individual peaks can help improve our understanding of changes in protein concentration in physiologic and pathologic conditions. Objective: The aim of this study was to verify the presence and identity the protein(s) in the prominent α‐globulin peak of orange‐winged parrots (Amazona amazonica), black kites (Milvus migrans), and rock pigeons (Columba livia). Methods: Heparinized plasma samples were obtained from 12 birds of each species. Agarose gel electrophoresis and total protein concentration were determined using standard techniques. One plasma sample from each species was then electrophoresed using high‐resolution agarose gels to isolate the α‐globulin band. Gel strips were digested in trypsin and peptides were extracted and analyzed using liquid chromatography with tandem mass spectrometry. De novo sequencing was used to identify the protein based on homology scoring against a protein database. Results: Electrophoresis verified the presence of a single prominent α‐globulin peak, usually in the α₁‐region, that had a median concentration of 9.4 g/L (range, 2.1–11.7 g/L, 21.6% of total protein) in parrots, 12.2 g/L (10.4–13.2 g/L, 35.9%) in kites, and 10.7 g/L (9.0–11.5 g/L, 40.0%) in pigeons. Mass spectrometry and sequencing analysis unequivocally identified the protein as a mature circulating form of apolipoprotein A‐I (apo A‐I) in all 3 species. Conclusions: Apo A‐I accounts for the prominent α‐globulin peak and comprises a major proportion of total protein concentration in diverse avian species. As a high‐density lipoprotein and negative acute phase protein with a pivotal role in cholesterol homeostasis, further study is warranted to determine the significance of changes in apo A‐I concentration in avian electrophoretograms.     

The canine prostate cancer cell line CHP‐1 shows over‐expression of the co‐chaperone small glutamine‐rich tetratricopeptide repeat‐containing protein α

Although androgen therapy resistance and poor clinical outcomes are seen in most canine prostate cancer cases, there are only a few tools for analysing canine prostate cancer by using a cell biological approach. Therefore, to evaluate androgen‐independent neoplastic cell growth, a new canine prostate cancer cell line (CHP‐1) was established in this study. CHP‐1 over‐expressed the co‐chaperone small glutamine‐rich tetratricopeptide repeat‐containing protein α (SGTA), which is over‐expressed in human androgen‐independent prostate cancer. The CHP‐1 xenograft also showed SGTA over‐expression. Although CHP‐1 shows poor androgen receptor (AR) signalling upon dihydrotestosterone stimulation, forced expression of AR enabled evaluation of AR signalling. Taken together, these results suggest that CHP‐1 will be a useful model for investigating the pathogenesis of androgen‐dependent and androgen‐independent canine prostate cancer.     

Effects of transforming growth factor‐β1 treatment on muscle regeneration and adipogenesis in glycerol‐injured muscle

Transforming growth factor (TGF)‐β1 is associated with fibrosis in many organs. Recent studies demonstrated that delivery of TGF‐β1 into chemically injured muscle enhances fibrosis. In this study, we investigated the effects of exogenous TGF‐β1 on muscle regeneration and adipogenesis in glycerol‐injured muscle of normal mice. Tibialis anterior (TA) muscles were injured by glycerol injection. TGF‐β1 was either co‐injected with glycerol, as an ‘early treatment’ group, or injected at day 4 after glycerol, as a ‘late treatment’ group and the TA muscles were collected at day 7 after initial injury. Myotube density was significantly lower in the early treatment group than in the glycerol‐injured group (without TGF‐β1 treatment). Moreover, the Oil red O‐positive area was significantly smaller in the early treatment group than in the late treatment group and glycerol‐injured group. Furthermore, TGF‐β1 treatment increased endomysial fibrosis and induced immunostaining of α‐smooth muscle actin. The greater inhibitory effects of early TGF‐β1 treatment than that of late TGF‐β1 treatment during regeneration in glycerol‐injured muscle suggest a more potent effect of TGF‐β1 on the initial stage of muscle regeneration and adipogenesis. Combination of TGF‐β1 with glycerol might be an alternative to enhance muscle fibrosis for future studies.