Induction of radical scavenging ability and suppression of lipid peroxidation in rat liver microsomes following whole-body, low-dose X-irradiation

Low-dose radiation induces renal SOD1 expression and activity in type 1 diabetic mice

PURPOSE

Oxidative stress plays a critical role in the pathogenesis of diabetic nephropathy (DN). As an antioxidant, superoxide dismutase (SOD)-1 deficiency exacerbates but SOD1 supplementation prevents diabetes-induced renal damage. Previously, we have demonstrated that repetitive exposure to low-dose radiation (LDR) at 25 mGy significantly prevents DN. Whether this prevention is related to SOD1 expression and activity remains unknown. The aim of the present study was to explore the effects of different methods of LDR treatment on SOD1 expression and activity in the kidneys of diabetic mice.

MATERIALS AND METHODS

C57BL/6J mice were induced with type 1 diabetes using streptozotocin (STZ). Diabetic mice were irradiated with whole-body X-rays at either a single dose of 25 mGy or 75 mGy, or three doses of 25 mGy and then sacrificed at different times. Body weight, blood glucose level, and renal SOD1 expression and activity were measured.

RESULTS

LDR had no impact on the body weights or blood glucose levels of the mice in either the normal or diabetic groups. A single exposure of LDR at 25 mGy did not preserve renal SOD1 expression and activity in diabetic mice, but a single exposure of LDR at 75 mGy or three exposures of LDR at 25 mGy could preserve them.

CONCLUSION

The stimulation of renal SOD1 expression and activity by a single or cumulative LDR of 75 mGy may be one of the preventive mechanisms of DN observed in the previous study.

Exhaled pentane as a possible marker for survival and lipid peroxidation during radiotherapy for lung cancer--a pilot study

To examine lipid peroxidation during radiotherapy (RT), exhaled pentane samples were collected from 11 lung cancer patients before RT and 30 and 120 min after the start of RT on days 1, 4 and 5 and at 30 and 40 Grays, if possible. Exhaled pentane samples were collected once from 30 healthy controls. Serum thiobarbituric-acid-reactive substances (TBARS) and conjugated dienes (CD) were obtained from patients on each exhaled air collection day. Lung cancer patients had higher exhaled pentane levels than controls (1.73 ng/L vs 0.83 ng/L, p=0.017). Exhaled pentane levels tended to decrease during the first RT day (p=0.075) and levels of CD decreased during the first week of RT (p=0.014). Higher pre-treatment pentane levels predicted better survival (p=0.003). Elevated exhaled pentane levels before RT may be due to the lipid peroxidation burden associated with cancer. The decrease of lipid peroxidation markers during RT may be attributable to enhanced antioxidant defense mechanisms.