Ultrastructural comparison of medial collateral ligament repair after single or multiple applications of GaAlAs laser in rats

Short term histopathological effects of GaAlAs laser on experimentally induced TMJ osteoarthritis in rabbits

The aim of this study was to evaluate the biostimulation (BS) effect of the gallium-aluminum-arsenide (GaAlAs) diode laser by histopathology with an experimental osteoarthritis (OA) model in the temporomandibular joints (TMJ) of rabbits, in the early period. GaAlAs diode laser is used for pain reduction in TMJ disorders. Twenty-four adult male New Zealand white rabbits were randomly divided into three equal groups: Control Group (CG), Study Group 1 (SG-1), and Study Group 2 (SG-2). Mono-iodoacetate (MIA) was administered to the right TMJs of all rabbits. The rabbits did not undergo any treatment for four weeks to allow the development of osteoarthritis. In SG-1, laser BS was applied to the rabbits at 940 nm, 5 W, and 15 J/cm2 in continuous wave mode at 48-hour intervals for 14 sessions; and in SG-2, laser BS was applied with the same parameters at 24-hour intervals for 28 sessions. Laser BS was not applied to the rabbits in CG. All rabbits were sacrificed simultaneously. The TMJ cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification were evaluated histopathologically. There was no statistically significant difference between the groups in terms of cartilage, osteochondral junction, chondrocyte appearance, and subchondral ossification values (p > 0.05). The laser BS protocol used in the study had no positive histopathological effects on TMJ OA in the early period.

Infrared low-level diode laser on serum chemokine MCP-1 modulation in mice

The effect of the low-level laser therapy (LLLT) in the modulation of cells related to inflammatory processes has been widely studied, with different parameters. The objective was to investigate the immediate and cumulative effect of infrared LLLT on chemokine monocyte chemotactic protein-1 (MCP-1) modulation in mice. Fifty-two isogenic mice were distributed in seven groups: control (n = 10, no surgical procedure), laser I (n = 7, surgical procedure and a single LLLT exposure 12 h after the surgery), laser II (n = 7, surgery followed by two LLLT exposures, 12 and 36 h after surgery), and laser III (n = 7, surgery followed by three LLLT exposures, 12, 36, and 60 h after surgery). For each group, a sham group (n = 21) underwent surgery without laser application. The animals in the laser groups received an infrared diode continuous laser exposure (AsGaAl, 780 nm wavelength, power of 20 mW, energy density of 10 J/cm(2), spot size of 0,04 cm(2)) on three points (20 s per point), and a final energy of 0.4 J. The animals were sacrificed 36 h (laser I and sham I groups), 60 h (laser II and sham II), and 84 h (laser III and sham III groups) after surgery. The MCP-1 concentrations were measured by cytometric bead array. There was no significant difference between the three periods in the sham group (p = 0.3). There was a lower concentration of MCP-1 in the laser III group compared to the laser I group (p = 0.05). The infrared LLLT showed a cumulative effect in the modulation of chemokine MCP-1 concentration. Three LLLT exposures were necessary to achieve the MCP-1 modulation.

Single session to infrared low level diode laser on TNF-alpha and IL-6 cytokines release by mononuclear spleen cells in mice: a pilot study

BACKGROUND AND OBJECTIVE

The results of low-level infrared laser (LLL) systemic action on inflammatory modulation process, specifically diminishing pro-inflammatory and producing anti-inflammatory cytokines are extremely controversial in the literature. More studies are necessary to clarify the biomodulation process. The main objective was to investigate the effect of a single session of an AsGaAl laser on spleen cells interleukin-6 (IL-6) and tumor necrosis factor - alpha (TNF-alpha) release, in vivo, in mice.

STUDY DESIGN/MATERIALS AND METHODS

In a pilot study, 18 isogenic mice were distributed in three groups: control (no surgical procedure, n = 6), sham (surgical procedure with three standard cutaneous incisions, followed by abdominal muscle incision followed by suture, n = 6) and LLL (same procedure followed by a single LLL exposure 12 hours after the procedure, n = 6). The animals in the LLL group received a single infrared continuous laser session (780 nm wavelength, power of 20 mW, energy density of 10 J/cm(2)) on three points (20 seconds per point), and final energy of 0.4 J. All animals of the sham and LLL groups were sacrificed 36 hours after surgical procedure; the spleen mononuclear cells were isolated and cultivated for 48 hours. The IL-6 and TNF-alpha were measured by the ELISA method.

RESULTS

IL-6 and TNF-alpha concentrations released by the mononuclear cells showed significant differences between the control and sham group (P < 0.07). However, there were no differences between the control and LLL group and between the sham and LLL groups (P > 0.07).

CONCLUSION

The single session of infrared LLL showed a tendency of decreasing the IL-6 and TNF-alpha release by mononuclear spleen cells in mice after application, although there was not a significant difference between the sham and LLL group. Conclusions regarding effectiveness of a single session procedure cannot be made due to the low statistical power of this pilot study.

Combining therapeutic laser and herbal remedy for treating ligament injury: an ultrastructural morphological study

OBJECTIVE

We examined the ultrastructural morphology (number of collagen fibrils, mean and mass-averaged diameter) of isolated and combined treatments of a therapeutic laser and herbs for medial collateral ligament (MCL) injury in rats.

MATERIALS AND METHODS

Twenty-eight rats, divided into seven groups: laser (L), herb (H), laser + herb (LH), laser control (LC), herb control (HC), laser sham (LS) and herb sham (HS), were studied. Right MCL of groups L, H, LH, LC and HC were transected, while that of LS and HS remained intact. Group L received 9 treatment sessions of GaAlAs laser with a dosage of 3.5 Jcm(-2); group H received herbal plaster treatment; groups LH had combined treatments of laser and herb; group LC had placebo laser; group LS had no treatment; groups HC and HS received only bandage without herb. All MCLs were analyzed using transmission electron microscopy at 3 weeks.

RESULTS

Differences (p < 0.05) existed in mean fibril diameters among groups. Core mass-averaged diameters of groups L and H were larger than the control groups (LC and HC). Fibril diameter of group LH (combined treatment) was even larger and approaching that of the intact MCL.

CONCLUSION

Combined therapeutic laser and herbal treatment hastened collagen fibril maturation in MCL repair.

Efeitos do laser de baixa potência sobre a dor e edema no trauma tendíneo de ratos

A dor e o edema são sinais, entre outros, que ocorrem durante a fase inflamatória no processo de cura de tendões lesados. A terapia antiinflamatória farmacológica recebe algumas críticas, com relação a seus efeitos deletérios para o reparo. Dessa forma, ganha corpo o uso de recursos físicos para o controle do processo. O objetivo do presente estudo foi avaliar o uso do laser de baixa potência sobre a dor e edema em tendão calcâneo de ratos submetidos a trauma experimental. Foram utilizados 28 ratos Wistar, divididos em quatro grupos: GC - submetido à lesão traumática e ao tratamento placebo; G2 - submetido à lesão e irradiado com laser 2J/cm²; G4 - submetido à lesão e irradiado com 4J/cm²; G8 - submetido à lesão e irradiado com 8J/cm². A lesão foi realizada com a queda de um peso sobre a face lateral do tendão calcâneo direito de cada animal, com energia de aproximadamente 0,40J. A dor foi avaliada pelo tempo de elevação da pata (TEP) do animal caminhando durante um minuto, sobre um cilindro metálico com 30cm de diâmetro em 3rpm; a avaliação do edema ocorreu através de paquimetria; os momentos de avaliação foram: pré-lesão, pós-lesão, pós-tratamento, duas horas, oito horas, 24 horas e 5º dia de lesão. O tratamento com laser 670nm ocorreu de forma pontual e diária. Os resultados mostraram aumentos do TEP e formação de edema em todos os grupos após a lesão; para os grupos tratados houve redução da dor e do edema, fato observado no grupo controle apenas com relação à diminuição de edema no 5º dia de placebo. Conclui-se que o tratamento com laser de baixa potência diminuiu dor e edema nos animais com trauma tendíneo, de forma dose-dependente.

The effect of therapeutic ultrasound intensity on the ultrastructural morphology of tendon repair

This study evaluated the effects of ultrasound intensity on the ultrastructural morphology of Achilles tendon healing. Twenty Sprague-Dawley rats with surgically hemi-transected Achilles tendons were randomly assigned into four groups of 0, 0.5, 1.2 and 2 W/cm(2) for ultrasound treatment, with five rats in each group. The treatments were administered with 1 MHz continuous ultrasound daily starting from day 5 after injury. On day 30, ultrathin slides of the Achilles tendons were prepared and examined with transmission electron microscopy. Results showed that the mean collagen fibril size of all treatment groups was higher than the control (p < 0.05). There was no significant difference in the collagen fibril size among the treatment groups. These findings suggest that therapeutic ultrasound can enhance the maturation of collagen fibrils of repairing tendons, and this was not dependent on the intensity of ultrasound applied.

Effects of low-voltage microamperage stimulation on tendon healing in rats

STUDY DESIGN

Randomized controlled prospective experimental study.

OBJECTIVES

To examine the effects of transcutaneous low-voltage microamperage stimulation (LVMAS) on the mechanical strength of Achilles tendon repair in rats at 4 weeks after injury.

BACKGROUND

Understanding the effect of LVMAS on the healing of injured tendons is hampered by the lack of related experimental studies, especially from the aspect of biomechanical outcome measures.

METHODS AND MEASURES

Fourteen 3-month-old male Sprague-Dawley rats received surgical transection to the medial portion of their right Achilles tendon. The rats were divided into a LVMAS group (n = 7) and control group (n = 7). From day 6 postsurgery onwards, the LVMAS group received daily treatment of transcutaneous LVMAS (2.5 V, 100 microA/cm2, 10 pulses per second, positive current) for a total of 22 sessions, while the control group received placebo LVMAS by the same investigator during that period. On day 31, the Achilles tendons were harvested for biomechanical testing for load relaxation, stiffness, and ultimate tensile strength along the longitudinal direction.

RESULTS

The normalized Achilles tendon ultimate tensile strength of the LVMAS group (mean +/- SD, 110.5% +/- 25.0%) was higher than that of the control group (75.3% +/- 20.8%) (P = .014), but no significant difference was found in normalized stiffness and load relaxation between the 2 groups (P = .239 and .350, respectively).

CONCLUSION

The results of this study suggest that the administration of transcutaneous LVMAS could improve healing and consequently the tensile strength of partially transected Achilles tendons of rats at 4 weeks after injury.