Effects of low-level light therapy on streptozotocin-induced diabetic kidney

Hyperglycemia causes oxidative damage in tissues prone to complications in diabetes. Low-level light therapy (LLLT) in the red to near infrared range (630–1000 nm) has been shown to accelerate diabetic wound healing. To test the hypothesis that LLLT would attenuate oxidative renal damage in Type I diabetic rats, male Wistar rats were made diabetic with streptozotocin (50 mg/kg, ip), and then exposed to 670 nm light at a dose of 9 J/cm2 once per day for 14 weeks. The activity and expression of catalase and the activity of Na K-ATPase increased in kidneys of light-treated diabetic rats, whereas the activity and expression of glutathione peroxidase and the expression of Na K-ATPase were unchanged. LLLT lowered the values of serum BUN, serum creatinine, and BUN/creatinine ratio. In addition, LLLT augmented the activity and expression of cytochrome c oxidase, a primary photoacceptor molecule in the mitochondrial respiratory chain, and reduced the formation of the DNA adduct 8-hydroxy-2′-deoxyguanosine in kidney. LLLT improved renal function and antioxidant defense capabilities in the kidney of Type I diabetic rats. Thus, 670 nm LLLT may be broadly applicable to the amelioration of renal complications induced by diabetes that disrupt antioxidant defense mechanisms.