Effects of Low Level Laser Therapy on Functional Capacity and DNA Damage of Patients With Chronic Kidney Failure

Chronic kidney disease (CKD) consists of kidney damage and progressive and irreversible loss of kidney function and in its later stage (terminal phase) is called chronic kidney failure (CKF). Although hemodialysis (HD) substitutes some of the lost renal functions, patients suffer from some changes that characterize uremic syndrome, such as peripheral motor neuropathy, osteomalacia, cardiac and musculoskeletal myopathies, anemia, among other alterations.

This study aims to verify the effects of low level laser therapy (LLLT) on functional capacity, DNA damage, lower limbs muscle strength, quadriceps muscle architecture, muscle pain and perception of lower limb fatigue, inflammatory profile, oxidative stress and quality of life of patients with chronic kidney failure on hemodialysis. Patients will be randomized into two groups: the control group and the LLLT group. The control group will only be evaluated and reassessed. The LLLT group in addition to the evaluations will receive LLLT three times a week for eight weeks during HD. The evaluations will be performed pre-intervention, after 4 and 8 weeks of therapy. However, the muscle architecture evaluation will be performed only at pre intervention and after 8 weeks.

The evaluations carried out are: a six-minute walk test for functional capacity; alkaline comet assay for DNA damage; sit-and-lift test, and load cell dynamometry for evaluation of lower limbs muscle strength; quadriceps ultrasonography for muscle architecture and echogenicity; visual analogue scale for pain; subjective perception of effort by Borg scale for fatigue; measurement of interleukins 6 and 10, tumor necrosis factor, reative C protein and muscle damage markers (lactate, creatine kinase) for the inflammatory profile; protein carbonylation, superoxide dismutase, catalase, total sulfuric acid and dichlorofluorescein diacetate for oxidative stress and application of the Kidney Disease and Quality-of-Life-Short-Form and EQ-5D questionnaires for quality of life.

The expected results at the end of the protocol are: greater distance covered in the walking test; reduction of DNA damage, increase in lower limbs strength; maintenance of muscle mass; reduction of pain and fatigue levels as well as the inflammatory profile and levels of oxidative stress, as well as improvement in the quality of life for the group LLLT.

Inclusion criteria

• Patients with chronic kidney failure on hemodialysis for more than 3 months;
• Dialysis with weekly frequency of 3 times/week;
• Adequate urea clearance rate during hemodialysis (Kt/V ≥ 1.2 or URR ≥65%).

Exclusion criteria

• Cognitive dysfunction
• Epidermal lesions at the site of laser application
• Patients with active carcinoma
• Patients with recent sequel of stroke (three months)
• Recent myocardium acute infarction (two months)
• Uncontrolled hypertension (SBP> 230 mmHg and DBP> 120 mmHg)
• Grade IV heart failure according to the New York Heart Association or decompensated
• Unstable angina
• Peripheral vascular changes in lower limbs such as deep venous thrombosis
• Disabling osteoarticular or musculoskeletal disease
• Uncontrolled diabetes (glycemia> 300mg/dL)
• Febrile condition and/or infectious disease
• Active smoking.