Rita de Cássia Marqueti

Androgenic-Anabolic Steroids Associated with Mechanical Loading Inhibit Matrix Metallopeptidase Activity and Affect the Remodeling of the Achilles Tendon in Rats:

Background The indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations. Purpose To study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program. Study Design Controlled laboratory study. Methods Wistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animals body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin–sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Results Morphological analyses of tendons showed that in group II, the most external layer that covers the tendon was thicker with aggregation of the collagen fibers, suggesting an increase in collagen synthesis. In group IV, an inflammatory infiltrate and fibrosis in tendons as well as a pronounced increase of the serum corticosterone level were observed. This training protocol upregulated matrix metallopeptidase activity, whereas anabolic-androgenic steroid treatment strongly inhibited this activity. The appearance of lytic bands with molecular masses of approximately 62 and 58 kDa suggests the activation of matrix metallopeptidase–2. Conclusion Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by downregulating matrix metallopeptidase activity, thus increasing the potential for tendon injury. Clinical Relevance Since the AAS abuse is so widespread, a better comprehension of the pathological effects induced by these drugs may be helpful for the development of new forms of therapy of AAS-induced lesions.

Comparison Between Linear and Daily Undulating Periodized Resistance Training to Increase Strength

Prestes, J, Frollini, AB, De Lima, C, Donatto, FF, Foschini, D, de Marqueti, RC, Figueira Jr, A, and Fleck, SJ. Comparison between linear and daily undulating periodized resistance training to increase strength. J Strength Cond Res 23(9): 2437-2442, 2009-To determine the most effective periodization model for strength and hypertrophy is an important step for strength and conditioning professionals. The aim of this study was to compare the effects of linear (LP) and daily undulating periodized (DUP) resistance training on body composition and maximal strength levels. Forty men aged 21.5 ± 8.3 and with a minimum 1-year strength training experience were assigned to an LP (n = 20) or DUP group (n = 20). Subjects were tested for maximal strength in bench press, leg press 45°, and arm curl (1 repetition maximum [RM]) at baseline (T1), after 8 weeks (T2), and after 12 weeks of training (T3). Increases of 18.2 and 25.08% in bench press 1 RM were observed for LP and DUP groups in T3 compared with T1, respectively (p ≤ 0.05). In leg press 45°, LP group exhibited an increase of 24.71% and DUP of 40.61% at T3 compared with T1. Additionally, DUP showed an increase of 12.23% at T2 compared with T1 and 25.48% at T3 compared with T2. For the arm curl exercise, LP group increased 14.15% and DUP 23.53% at T3 when compared with T1. An increase of 20% was also found at T2 when compared with T1, for DUP. Although the DUP group increased strength the most in all exercises, no statistical differences were found between groups. In conclusion, undulating periodized strength training induced higher increases in maximal strength than the linear model in strength-trained men. For maximizing strength increases, daily intensity and volume variations were more effective than weekly variations.

Biomechanical responses of different rat tendons to nandrolone decanoate and load exercise

Androgenic‐anabolic steroids (AAS) have been associated with an increased incidence of tendon rupture. The aim of this study was to compare the biomechanical properties of the rat calcaneal tendon (CT), superficial flexor tendon (SFT), and deep flexor tendon (DFT), and to determine the effect of jump training in association with AAS. Animals were separated into four groups: sedentary, trained, AAS‐treated sedentary rats (AAS), and AAS‐treated and trained animals. Mechanical testing showed that the CT differed from the DFT and SFT, which showed similar mechanical properties. Jump caused the CT to exhibit an extended toe region, an increased resistance to tensional load, and a decreased elastic modulus, characteristics of an elastic tendon capable of storing energy. AAS caused the tendons to be less compliant, and the effects were reinforced by simultaneous training. The DFT was the most affected by training, AAS, and the interaction of both, likely because of its involvement in the toe‐off step of jumping, which we suggest is related to the rapid transmission of force as opposed to energy storage. In conclusion, tendons are differently adapted to exercise, but responded equally to AAS, showing reduced flexibility, which is suggested to increase the risk of tendon rupture in AAS consumers.

Cryotherapy Reduces Inflammatory Response Without Altering Muscle Regeneration Process and Extracellular Matrix Remodeling of Rat Muscle

The application of cryotherapy is widely used in sports medicine today. Cooling could minimize secondary hypoxic injury through the reduction of cellular metabolism and injury area. Conflicting results have also suggested cryotherapy could delay and impair the regeneration process. There are no definitive findings about the effects of cryotherapy on the process of muscle regeneration. The aim of the present study was to evaluate the effects of a clinical-like cryotherapy on inflammation, regeneration and extracellular matrix (ECM) remodeling on the Tibialis anterior (TA) muscle of rats 3, 7 and 14 days post-injury. It was observed that the intermittent application of cryotherapy (three 30-minute sessions, every 2 h) in the first 48 h post-injury decreased inflammatory processes (mRNA levels of TNF-α, NF-κB, TGF-β and MMP-9 and macrophage percentage). Cryotherapy did not alter regeneration markers such as injury area, desmin and Myod expression. Despite regulating Collagen I and III and their growth factors, cryotherapy did not alter collagen deposition. In summary, clinical-like cryotherapy reduces the inflammatory process through the decrease of macrophage infiltration and the accumulation of the inflammatory key markers without influencing muscle injury area and ECM remodeling.

Resistance training improves body composition and increases matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles of diet-induced obese rats

OBJECTIVE: We investigated the influence of resistance training on body composition and matrix metalloproteinase 2 activity in skeletal muscles of rats fed a high-fat diet. METHODS: Thirty-two Wistar rats were divided into four experimental groups (n = 8/each) according to diet and exercise status: Control (standard diet), Obese Control (high-fat diet), Resistance Training (standard diet) and Obese Resistance Training (high-fat diet) groups. Animals were fed a high-fat diet for 12 weeks to promote excessive weight gain. Resistance Training groups performed 12 weeks of training periods after this period in a vertical ladder three times/week. Fat percentage, fat-free mass and fat mass were assessed using dual-energy X-ray absorptiometry, and matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles was analyzed using zymography. RESULTS: Resistance training significantly reduced body and fat masses and fat percentages in both trained groups (p<0.05). The maximal carrying load between trained groups was not different, but relative force was higher in the Resistance Training group (p<0.05). Of note, increased matrix metalloproteinase 2 activity was noted in the tested muscles of both trained groups (p<0.05). CONCLUSION: In conclusion, altered body composition and muscle matrix metalloproteinase 2 activity promoted by excessive weight gain were positively modified by resistance training.

Acute eccentric resistance exercise decreases matrix metalloproteinase activity in obese elderly women

The association of ageing with obesity commits elderly women and has been correlated with multiple degenerative processes, which could be occasioned by an enhancing in levels of matrix metalloproteinase‐2 and metalloproteinase‐9 (MMPs) as well by an cytokine unbalance that included an enhancing on interleukin‐6 (IL‐6). Furthermore, other factors could be also related to degenerative process, as they could be reduced by eccentric resistance exercise (ERE), which seems particularly important to initiate resistance training in obese older adults. In this view, this study aims to determinate the effects of an acute ERE session on serum MMP‐2, MMP‐9 and IL‐6 in elderly obese women. Ten elderly obese women participated in this study and completed a 10 repetitions maximum test (10 RM) utilizing leg extension exercise. Subjects then completed an acute ERE session consisting of seven sets of 10 repetitions at 110% of 10 RM with a rest of 3 min between sets. Blood samples were collected before, immediately after, 3, 24 and 48 h following the ERE session. Zymograms were utilized to measure the MMP‐2 and MMP‐9 enzymes from all individuals. Moreover, IL‐6 concentration was also determinated. After ERE session, MMP‐2 and MMP‐9 decreased, remaining significantly below baseline values after 48 h (P<0·05). Although not statistically significant, there was a tendency for IL‐6 to decrease 48 h after the ERE when compared with 3 h (P = 0·06). An acute ERE session decreases MMP‐9, MMP‐2 and IL‐6 in elderly obese women, possibly indicating a transient protection against the low grade inflammation present in this specific population.

Nandrolone Inhibits MMP-2 in the Left Ventricle of Rats

The indiscriminate use of anabolic-androgenic steroids has been shown to induce left ventricular dysfunctions. The main objective of the present study was to investigate the effects of nandrolone decanoate on matrix metalloprotease (MMP-2) activity and protein level in the left ventricle (LV) of rats after 7 weeks of mechanical load exercise. Wistar rats were grouped into: sedentary (S); nandrolone decanoate-treated sedentary (AAS); trained without AAS (T) and trained and treated with AAS (AAST). Exercised groups performed a 7-weeks water-jumping program. Training significantly increased the MMP-2 activity by zymography and the protein level by Western blotting analysis. However, the AAS treatment abolished both the increase in MMP activity and protein level induced by exercise. These results suggest that AAS may impair cardiac tissue remodeling which may lead to the heart malfunction.

Tendon structural adaptations to load exercise are inhibited by anabolic androgenic steroids

The present study investigated the structural changes in the rat calcaneal tendon (CT), superficial flexor tendon (SFT), and deep flexor tendon (DFT) in response to jump exercises and anabolic androgenic steroids (AAS). Animals were divided into four groups: sedentary, trained, AAS‐treated sedentary rats, and AAS‐treated trained animals. Training increased the volume density (Vv%) of blood vessels in all regions of the CT and DFT, cell Vv% in the peritendinous sheath of the proximal and distal regions of the SFT and proximal region of DFT, and cell Vv% in the tendon proper of the proximal and distal regions of the SFT and DFT. The combination of AAS and load exercises showed little increased blood vessel Vv% at the proximal region of the CT, intermediate region of the SFT, and all regions of the DFT as opposed to an increase in adipose cell Vv% in the CT proximal region. The AAS reduced the levels of hydroxyproline in the proximal region of the DFT and in the distal region of the STF. In conclusion, exercise promoted benefits to the adaptation of the tendons to overload. These effects were absent when load exercise was combined with AAS. The abusive consumption of AAS contributes to tendon inertness and rigidity, and increases the potential risk of injury.

Resistance training regulates gene expression of molecules associated with intramyocellular lipids, glucose signaling and fiber size in old rats

Sarcopenia is a complex multifactorial process, some of which involves fat infiltration. Intramyocellular lipid (IMCL) accumulation is postulated to play a role on sarcopenia during aging, which is believed to be due alterations in glucose homeostasis in the skeletal muscle. Sarcopenia, along with intramuscular lipids, is associated with physical inactivity. Resistance training (RT) has been indicated to minimize the age-induced muscle skeletal adaptations. Thus, we aimed to investigate the effects of RT on mRNA levels of regulatory components related to intramyocellular lipid, glucose metabolism and fiber size in soleus and gastrocnemius muscles of aged rats. Old male rats were submitted to RT (ladder climbing, progressive load, 3 times a week for 12 weeks). Age-induced accumulation of IMCL was attenuated by RT, which was linked to a PPARy-mediated mechanism, concomitant to enhanced regulatory components of glucose homeostasis (GLUT-4, G6PDH, Hk-2 and Gly-Syn-1). These responses were also linked to decreased catabolic (TNF-α, TWEAK/Fn14 axis; FOXO-1, Atrogin-1 and MuRF1; Myostatin) and increased anabolic intracellular pathways (IGF-1-mTOR-p70S6sk-1 axis; MyoD) in muscles of trained aged rats. Our results point out the importance of RT on modulation of gene expression of intracellular regulators related to age-induced morphological and metabolic adaptations in skeletal muscle.

Multiple cryotherapy applications attenuate oxidative stress following skeletal muscle injury

ABSTRACT Objectives: To investigate the effects of multiple cryotherapy applications after muscle injury on markers of oxidative stress. Methods: Following cryolesion-induced skeletal muscle injury in rats, ice was applied at the injured site for 30 minutes, three times per day, on the day of injury, and for 2 days after injury. To determine the effect of the cryotherapy treatment on markers of oxidative stress, biochemical analyses were performed 3, 7, and 14 days after injury. Results: Compared with non-treated animals, cryotherapy reduced dichlorofluorescein at 7 and 14 days post-injury and thiobarbituric acid reactive substances levels at 3 and 7 days post-injury (P < 0.05). Additionally, cryotherapy maintained methyl thiazol tetrazolium reduction levels compared to the control group at all analyzed time points (P > 0.05), whereas non-treated groups demonstrated lower levels than the control group (P < 0.05). Superoxide dismutase activity at 7 and 14 days post-injury and catalase activity at 3 days post-injury were lower in cryotherapy groups compared with non-treated groups (P < 0.05). Cryotherapy prevented the reduction of non-protein thiol levels and maintained within control group level, at 3 days post-injury (P = 0.92). Discussion: Cryotherapy reduced the production of reactive oxygen species after muscle injury, resulting in an attenuated response of the antioxidant system. These findings suggest that using multiple cryotherapy applications is efficient to reduce oxidative stress.