Photobiomodulation mechanisms in the kinetics of the wound healing process in rats.

OBJECTIVES: The healing process of cutaneous lesions is considered a complex event divided into distinct and overlapping phases, which responds satisfactorily to photobiomodulation (PBM). PBM is indicated as a therapeutic resource capable of assisting tissue repair. The present study aimed to analyze the kinetics of cutaneous wounds healing process after application of the GaAlAs laser for treating wounds on the dorsum of rats. MATERIALS AND METHODS: This study was approved by the Animal Ethics Committee of UFSCar. The animals were divided into 2 groups (n = 10); control group (CG) used 0.9% saline solution and the laser group (LG) used GaAlAs, 670 nm continuous pulse, 30 mW power, 14.28 J/cm2 energy density, irradiating 1 point per wound for 30s, totaling 15 consecutive days of treatment. Samples were collected on the 4th, 11th and 16th days for histological analysis of HE, Picrosirius-Red, immunohistochemistry (Collagen1, TNF-α, VEGF). Statistical analyzes used the one-way ANOVA test for intra and inter group evaluations, and the Tukey post-test. Level of significance was set at p < 0.05. RESULTS: The histopathological analysis (HE) showed a statistically significant difference for lower values of inflammatory infiltrate in LG versus CG on the 16th day; and for the increase of collagen in the 11th and 16th days of treatment. There was a statistically significant difference in the increase of VEGF on the 11th day for LG; decrease of TNF-α on the 4th and 11th day for LG, and increase of collagen type 1 on the 4th and 16th days for LG. The birefringence analysis of the percentage of collagen fibers presented on the 11th day of treatment revealed a greater quantity and significant statistical difference. Collagen fibers showed improved organization and arrangement on the 11th day for LG. CONCLUSION: Our results show that PBM is effective in helping the kinetics of the cutaneous wound healing process in rats and promotes the necessary stimuli for the satisfactory evolution of healing process, ultimately leading to structurally desirable tissue.

MMP(-2) expression in skeletal muscle after strength training.

The aim of this study was to assess the effects of resistance training on ladders (RTL) on MMP(-2) expression and blood lactate concentration [La-]. 30 male (3 months of age), albino rats were divided into 3 groups: sedentary control (SC, n=10), low resistance exercise training (Low-IntRT, n=10) and high-intensive exercise training (High-IntRT, n=10). Animals of High-IntRT were submitted to a progressively increasing overload in relation to body weight until exhaustion, while the Low-IntRT group performed the same exercise regimen with no external load. The program had a frequency of 3 times per week over 8 weeks. MMP(-2) expression of tibialis anterior muscle and [La-] were measured. While there was a significant increase of MMP(-2) (pro-form) in both groups, only High-IntRT significantly increased MMP(-2) in active-form (p<0.05). Both trained groups exhibited an increase in [La-] when compared to controls, however, the increase in [La-] was significantly higher in the High-IntRT compared to Low-IntRT (p<0.05). Strong correlation was found between MMP(-2) (active form) and [La-] in High-IntRT (r=0.91). RTL in using low and high-intensity exercise can serve as a model to demonstrate different responses of MMP(-2) expression in an animal model. It appears active form expression of MMP(-2) is modulated by exercise intensity.

Physico-chemical and antifungal properties of protease inhibitors from Acacia plumosa.

This study was aimed at investigating the purification, biological activity, and some structural properties of three serine protease inhibitors isoforms, denoted ApTIA, ApTIB, and ApTIC from Acacia plumosa Lowe seeds. They were purified from the saline extract of the seeds, using Superdex-75 gel filtration and Mono-S ion exchange chromatography. They were further investigated by mass spectrometry, spectroscopic measurements, surface plasmon resonance, and inhibition assays with proteases and phytopathogenic fungi. The molecular mass of each isoform was estimated at ca. 20 kDa. Each contained two polypeptide chains linked by a disulfide bridge, with different isoelectric points that are acidic in nature. The N-terminal sequences of both chains indicated that they were Kunitz-type inhibitors. Circular dichroism (CD) analyses suggested the predominance of both disordered and beta-strands on ApTI isoforms secondary structure, as expected for beta-II proteins. In addition, it was observed that the proteins were very stable, even at either extreme pH values or at high temperature, with denaturation midpoints close to 75 degrees C. The isoinhibitors could delay, up to 10 times, the blood coagulation time in vitro and inhibited action of trypsin (Ki 1.8 nM), alpha-chymotrypsin (Ki 10.3 nM) and kallikrein (Ki 0.58 microM). The binding of ApTIA, ApTIB, and ApTIC to trypsin and alpha-chymotrypsin, was investigated by surface plasmon resonance (SPR), this giving dissociation constants of 0.39, 0.56 and 0.56 nM with trypsin and 7.5, 6.9 and 3.5 nM with alpha-chymotrypsin, respectively. The growth profiles of Aspergillus niger, Thielaviopsis paradoxa and Colletotrichum sp. P10 were also inhibited by each isoforms. These three potent inhibitors from A. plumosa may therefore be of great interest as specific inhibitors to regulate proteolytic processes.