Fernando Augusto Vasilceac

Men with Early Degrees of Knee Osteoarthritis Present Functional and Morphological Impairments of the Quadriceps Femoris Muscle

ObjectiveQuadriceps muscle weakness is common in knee osteoarthritis (OA). Reasons for weakness may include atrophy, reduction in the muscle fibers number, and changes in the muscle activation. It is uncertain when these muscular changes begin to appear. Therefore, the purpose of this study was to determine whether men with early stages of knee OA already had functional and quadriceps muscle morphologic alterations. DesignForty men were divided into two groups: control group (healthy subjects) and OA group (subjects with knee OA). A biopsy of the vastus lateralis muscle was performed for morphometric analysis. Isokinetic evaluation of knee extensor torque, concentric and eccentric (90 and 180 degrees/sec), was performed simultaneously with vastus lateralis electromyographic activity evaluation. ResultsSignificant differences were found in knee extensor torque (P < 0.05) and in normalized root mean square (P < 0.01) during the eccentric contractions (both velocities), with higher values for the control group. No differences were found during concentric contractions. The OA group presented greater values of the minimum diameter of type 1 fibers and greater proportion and relative cross-sectional area of type 2b fibers (P < 0.05). ConclusionsMen with early stages of knee OA do not present alterations of concentric strength but had decreased eccentric strength and morphologic quadriceps muscle changes, indicating neuromuscular adaptations.

Progression of Articular Cartilage Degeneration after Application of Muscle Stretch

The aim of study was to evaluate the progression of the ankle articular cartilage alterations after a post-immobilization muscle stretching. Twenty-nine Wistar rats were separated into five groups: C—control, S—stretched, SR—stretch recovery, IS—immobilized and stretched, and ISR—immobilized stretched recovery. The immobilization was maintained for 4 weeks and the left ankle was then stretched manually through a full dorsal flexion for 10 times for 60 s with a 30 s interval between each 60 s period, 7 days/week for 3 weeks. The recovery period was of 7 weeks. At the end of the experiment, the left ankles were removed, processed in paraffin, and stained in hematoxylin-eosin and safranin O. Two blinded observers evaluated the articular cartilage using the Mankin grading system (cellularity, chondrocyte cloning, and proteoglycan content) through light microscopy, and performed the morphometry (cellularity, total thickness, non-calcified thickness, and calcified thickness measures). Both the Mankin grading system and the morphometric analysis showed that the ISR group presented the most increased cellularity among the groups. The IS and SR groups showed the highest proteoglycan loss, and the ISR group showed the same content of proteoglycan observed in the C group. No significant differences were found in the chondrocyte cloning, the total cartilage thickness, the non-calcified cartilage thickness, and the calcified cartilage thickness among the groups. The results suggest that the cartilage can recover the proteoglycan loss caused by immobilization and stretching, probably because of the increased chondrocyte density. Therefore, the ankle articular cartilage responded as to repair the metabolic deficits.

Effects of low-level laser therapy on cartilage repair in an experimental model of osteoarthritis

Abstract Objective: The aim of this study was to evaluate the effects of low level laser therapy (LLLT) on the degenerative process in the articular cartilage after an anterior cruciate ligament transection (ACLT) model in rats. Methods: Eighty male rats (Wistar) were divided into four groups: 1.) intact control group (CG), 2.) injured control group (ICG), 3.) injured laser-treated group at 10 J/cm2 (L10) and 4.) injured laser-treated group at 50 J/cm2 (L50). Animals were divided into 2 subgroups, with different periods of sacrifice (5 and 8 weeks post-surgery). The ACLT was used to induce osteoarthritis (OA) in the knees of the rats. LLLT started 2 weeks after the surgery and it was performed for 15 and 30 sessions, respectively using a 685-nm laser, at 10 and 50 J/cm2. Qualitative and semi-quantitative histologic, morphometric and immunohistochemistry analyses were performed. Results: Initial signs of tissue degradation could be observed 5 weeks post-ACLT, evidenced by the decrease of proteoglycan concentration and increase in cartilage thickness of the ICG. After 8 weeks post-surgery, analysis showed a progression of the degenerative processes in the ICG revealed by the increased cellularity and higher TNF-α, IL1-β and MMP-13 immunoexpression. LLLT was able to modulate some of the aspects relating to the degradative process, such as biomodulation of the number of chondrocyte proliferation, prevention of proteoglycan loss, and decrease of MMP-13 immunoexpression. Conclusion: This study showed that the 685-nm laser irradiation, especially at 10 J/cm2, prevented features related to the articular degenerative process in the knees of rats.

Expression of receptors of advanced glycation end product (RAGE) and types I, III and IV collagen in the vastus lateralis muscle of men in early stages of knee osteoarthritis.

Abstract Alterations in the contractile and non-contractile proteins of the skeletal muscle may reduce muscle function in knee osteoarthritis (OA), and the formation and accumulation of advanced glycation end products, particularly in collagen, can influence the quality of these muscle proteins. The objective of this study was to evaluate the reactivity of types I, III and IV collagen and the expression and localization of receptor for advanced glycation end products (RAGE) in the vastus lateralis (VL) muscle in early stages of knee OA. The hypothesis was that these patients present a higher expression of RAGE and increased immunoreactivity in the collagen. Thirty-five men were divided into two groups: the control group (CG; n = 17) and the osteoarthritis group (OAG; n = 18). All participants were submitted to a biopsy of the VL. The muscle samples were analyzed by immunohistochemistry for collagen and for RAGE and laminin. The expression of RAGE was counted (intracellular, extracellular and total). Students t-test for independent samples and Mann–Whitney U test were used for the RAGEs intergroup analysis (α ≤ 0.05). A semiquantitative analysis was performed to assess the collagen reactivity. No significant differences were observed in the intracellular, extracellular or total localization of RAGE (p > 0.05). Higher immunoreactivity was observed in the OAG for all types of collagen, with more reactivity for collagen III and IV. We concluded that in the initial stages of knee OA, no differences were observed for RAGE levels between the groups. However, the OAGs higher collagen expression may represent adaptations for reducing muscle stiffness and avoiding injury.

Muscle Stretching after Immobilization Applied at Alternate Days Preserves Components of Articular Cartilage

We compared the response of articular cartilage subjected to muscle stretching at different frequencies after joint immobilization. Wistar rats with immobilized left hind limbs were classified into the following groups: immobilization, immobilization followed by muscle stretching applied daily (group IS7) or three times a week (IS3), muscle stretching applied daily (S7) or three times a week (S3), and a control group (C) that underwent no intervention. We then evaluated the cartilage for cellularity, loss of proteoglycans, collagen density, and immunostaining of fibronectin and chondroitin 4-sulfate. Group IS7 showed a significant increase in cellularity and significant loss of proteoglycan compared with the control. In addition, IS7 group had less proteoglycan than IS3. Thin collagen fibrils were significantly reduced in IS7 rats, compared with IS3 and C. There was a significant decrease in the amount of thick fibrils in all groups compared with the control. Groups IS7 and IS3 showed significantly more intense fibronectin immunostaining than the other groups. Our results show that if applied daily after immobilization, muscle stretching is harmful to articular cartilage. However, when applied on alternate days, muscle stretching preserves the components of articular cartilage. We suggest that the latter frequency is more suitable for treatment.