Histopathological changes in supraspinous ligaments, ligamentum flava and paraspinal muscle tissues of patients with ankylosing spondylitis.

OBJECTIVE: To examine the histopathological changes in spinal tissues of ankylosing spondylitis (AS) patients. METHODS: Tissue samples from 10 AS patients and 10 control subjects were obtained. Hematoxylin and eosin, picrosirius, Masson and van Gieson stainings were utilized to determine the pathological changes in tissues. Ultrastructural alterations were examined by electronic microscopy. Proteoglycan levels were assessed by enzyme-linked immunosorbent assays (ELISA). Matrix metalloproteinase-3 (MMP-3), transforming growth factor-ß1 (TGF-ß1) and tumor necrosis factor-α (TNF-α) levels were evaluated by immunohistochemistry. RESULTS: Our results demonstrate that the density of collagen fibrils was reduced in the supraspinous ligaments of AS tissue and fibrils were loosely and irregularly organized as compared to a regular distribution of collagen fibrils in controls. In ligamentum flava from AS patients, activated fibroblasts with enlarged nuclei were detected, while the number of elastic fibers was greatly decreased. Paraspinal muscle tissues of AS patients exhibited increased collagen fibril accumulation and atrophy. Significantly decreased proteoglycan and elevated MMP-3 levels were found in supraspinous ligament samples from AS patients (P < 0.01). Additionally, the levels of TGF-ß1 in ligamentum flava and paraspinal muscle tissues of AS patients were increased (P < 0.01). The expression of TNF-α was also upregulated in the ligamentum flavum (P < 0.01), with no significant difference in the paraspinal muscle between control and AS patients (P > 0.05). CONCLUSIONS: Our findings reveal histopathological changes that occur in certain spinal tissues of AS patients and suggest that increased levels of MMP-3 and TGF-ß1 may contribute to the pathogenesis of AS.

Dietary ractopamine influences sarcoplasmic proteome profile of pork Longissimus thoracis.

Dietary ractopamine improves pork leanness, whereas its effect on sarcoplasmic proteome has not been characterized. Therefore, the influence of ractopamine on sarcoplasmic proteome of post-mortem pork Longissimus thoracis muscle was examined. Longissimus thoracis samples were collected from carcasses (24 h post-mortem) of purebred Berkshire barrows (n=9) managed in mixed-sex pens and fed finishing diets containing ractopamine (RAC; 7.4 mg/kg for 14 days followed by 10.0 mg/kg for 14 days) or without ractopamine for 28 days (CON). Sarcoplasmic proteome was analyzed using two-dimensional electrophoresis and mass spectrometry. Nine protein spots were differentially abundant between RAC and CON groups. Glyceraldehyde-3-phosphate dehydrogenase and phosphoglucomutase-1 were over-abundant in CON, whereas serum albumin, carbonic anhydrase 3, L-lactate dehydrogenase A chain, fructose-bisphosphate aldolase A, and myosin light chain 1/3 were over-abundant in RAC. These results suggest that ractopamine influences the abundance of enzymes involved in glycolytic metabolism, and the differential abundance of glycolytic enzymes could potentially influence the conversion of muscle to meat.

Histological characterization and biochemical analysis of paraspinal muscles in neuromuscularly healthy subjects.

INTRODUCTION: There are no generally accepted histopathological reference values in paraspinal skeletal muscle biopsies. METHODS: We examined multifidii muscle biopsies from 20 neuromuscularly healthy subjects using routine histological stains and biochemical analyses of respiratory chain enzymes. RESULTS: Staining showed incomplete myopathic features, such as increased variability in fiber size, type 1 hypertrophy, rounded fiber shape, endomysial fibrosis, and replacement by adipose tissue. Acid phosphatase reaction was positive in up to 35% of the selected muscle fibers. Mitochondrial changes were obvious but revealed no selective age dependence. Reduced complex I, cytochrome c oxidase (COX), and citrate synthase (CS) could be observed. CONCLUSIONS: Because the increased variability in morphological details can easily be misinterpreted as myopathic changes, analysis of paraspinal muscles should take into consideration that incomplete myopathic features and reduced oxidative enzyme activities for complex I, COX, and CS are normal variations at this location.

Breed and dietary linseed affect gene expression of enzymes and transcription factors involved in n-3 long chain polyunsaturated fatty acids synthesis in longissimus thoracis muscle of bulls.

N-3 long-chain (LC) PUFA are known to be beneficial for human development and health. These properties explain the increasing interest in promoting n-3 LC PUFA deposition in bovine muscles, leading to healthier meats. In this context, this study aimed to identify possible limiting steps in the bioconversion of 18:3n-3 into n-3 LC PUFA in the longissimus thoracis (LT) muscle of 36 Aberdeen Angus, Limousin, and Blond d'Aquitaine bulls (n = 12 per breed) that were fed, for the 105-d finishing period, either a concentrate-based diet (25% molasses straw to 75% concentrate, on a raw basis; CON) or the same CON diet supplemented with extruded linseed (44.5 g lipid/kg diet DM) mixed into the concentrate (LINS). The fatty acid (FA) composition of the LT muscle was determined by GLC, and the mRNA abundances for enzymes and transcription factors involved in n-3 LC PUFA synthesis were determined by quantitative real-time PCR. The total lipid concentration in the LT muscle was approximately 2.4-fold greater (P < 0.001) in Angus bulls than in the other breeds and composed of the greatest n-3 PUFA content (P < 0.001) including 18:3n-3 (P < 0.001) and n-3 LC PUFA (P < 0.02), primarily 20:5n-3 (P < 0.007) and 22:5n-3 (P < 0.04). These data were associated with a lesser gene expression (P < 0.02) of 2 enzymes [acyl-CoA oxidase 1 (ACOX1) and L-bifunctional protein (L-PBE)] and 2 transcription factors [liver X receptors (LXR) α and ß] in the LT muscle of Angus bulls compared with gene expression in Limousin bulls. Moreover, the mRNA of elongase 5 was only present in trace amounts in the LT muscle of the 3 breeds. The addition of linseed to the diet resulted in greater deposition of 18:3n-3 (P < 0.001) in the LT muscles of the 3 breeds, without any major changes (P > 0.34) in the n-3 LC PUFA content. Dietary linseed stimulated (P < 0.04) the gene expression of all enzymes and transcription factors involved in n-3 LC PUFA synthesis except elongases 2 and 5 (P > 0.19), the expression of which remained weak and was not inducible. These results reveal a limited capacity for n-3 LC PUFA synthesis from 18:4n-3 (substrate of elongase 5) in the LT muscles of Blond d'Aquitaine, Limousin, and Angus bulls. Therefore, further investigations on the cellular regulation of elongase gene expression are needed to identify the physiological or nutritional factors that efficiently stimulate elongase expression in beef cattle.