Evaluation of low-level laser therapy on skeletal muscle ischemia-reperfusion in streptozotocin-induced diabetic rats by assaying biochemical markers and histological changes.

The purpose of the present study was to assess the effects of low-level laser therapy (LLLT) on skeletal muscle ischemia-reperfusion (IR) injuries in streptozotocin-induced diabetic rats. Twenty male Wistar rats were randomly assigned into two experimental groups, as follows: the diabetic IR group (G1, n = 10) and the diabetic IR + LLLT group (G2, n = 10). Ischemia was induced in anesthetized rats from the right femoral artery clipping for 2 h, followed by a reperfusion for 24 h. Then, the laser irradiation (K30 handheld probe, AZOR, Technica, Russia, 650 nm, 30 mW, surface area = 1 cm(2), energy density = 1.8 J/cm(2)) was carried out by irradiating the rats over a unique point on the skin over the middle region of the right gastrocnemius muscle belly three times (every 8 h), starting after initiating the reperfusion for 3 min. At the end of the reperfusion period, rats were anaesthetized and blood samples were collected and used for the estimation of pO2, pCO2, pH, HCO3, serum creatine phosphokinase (CPK), and lactate dehydrogenase (LDH). Subsequently, the right gastrocnemius muscle samples were taken for wet/dry weight ratio assessment and histological/biochemical examination. The pO2, pCO2, HCO3, and pH levels were similar for both groups (P > 0.05). The serum LDH and CPK levels were significantly lower (P < 0.05) for G2 compared to G1. In comparison to G1, tissue malondialdehyde level in G2 was significantly decreased (P < 0.05). In G2, superoxide dismutase activity was significantly increased compared to G1 (P < 0.05). Unlike G2, a significant decrease in the activity of catalase was observed in G1 (P < 0.05). The wet/dry ratio in G1 was significantly higher than that of G2 (P < 0.05). Histological examination confirmed that the extent of muscle changes in G1 was higher than G2 (P < 0.05). Finally, according to this study, LLLT has a beneficial effect on the IR muscle injury treatment in the diabetic rats. Therefore, we suggest that further research needs to be conducted using different laser parameters and examining response over a longer period of tissue recovery.