It has been demonstrated that
reactive oxygen species (ROS) formation and oxidative damage markers are increased after muscle damage. Recent studies have demonstrated that
low-level laser therapy (
LLLT) modulates many biochemical processes mainly those related to reduction of muscular injures, increment of mitochondrial respiration and
ATP synthesis, as well as acceleration of the healing process. The objective of the present investigation was to verify the influence of
LLLT in some parameters of muscular injury, oxidative damage,
antioxidant activity, and synthesis of
collagen after traumatic muscular injury. Adult male Wistar rats were divided randomly into three groups (n = 6), namely,
sham (uninjured muscle), muscle injury without treatment, and muscle injury with
LLLT (
GaAs, 904 nm). Each treated point received 5 J/cm(2) or 0.5 J of energy density (12.5 s) and 2.5 J per treatment (five regions).
LLLT was administered 2, 12, 24, 48, 72, 96, and 120 h after muscle
trauma. The serum
creatine kinase activity was used as an index of skeletal muscle injury.
Superoxide anion,
thiobarbituric acid reactive substance (
TBARS) measurement, and
superoxide dismutase (SOD) activity were used as indicators of oxidative stress. In order to assess the synthesis of
collagen, levels of
hydroxyproline were measured. Our results have shown that the model of traumatic injury induces a significant increase in serum
creatine kinase activity,
hydroxyproline content,
superoxide anion production,
TBARS level, and activity of SOD compared to control.
LLLT accelerated the muscular healing by significantly decreasing
superoxide anion production,
TBARS levels, the activity of SOD, and
hydroxyproline content. The data strongly indicate that increased ROS production and augmented
collagen synthesis are elicited by traumatic muscular injury, effects that were significantly decreased by
LLLT.