[Protective roles of vitamin E and coenzyme Q10 in the inner ear mitochondrial DNA 4834 bp deletion mutation of rats].

Objective: To explore the protective roles of vitamin E and coenzyme Q10 in the inner ear mitochondrial DNA 4834 bp deletion mutation of rats.

Methods: Forty-six Wistar rats were randomly divided into three groups. The rats of group A (18 rats) had admitted adriamycin 1 mg/kg by intraperitoneal injection twice a week and had taken vitamin E 50 mg/kg, coenzyme Q10 10 mg/kg orally everyday for three months. Group B (18 rats) was given the same dose of adriamycin as group A and saline instead of vitamin E and coenzyme Q10. Group C (10 rats) was given Saline only. The inner ear tissue was harvested and mitochondrial DNA was amplified to identify t he 4834 bp deletion mutation by nested-primer polymerase chain reaction (nested-PCR) technique. And the serum glutathione peroxidase (GSH-PX) activity was measured.

Results: The incidence of mitochondrial DNA 4834 bp deletion mutation of group A was 23.08% (3/13), group B was 68.75% (11/16), and group C was 0 (0/8). The mutation incidence of group A was significantly lower than group B (Fisher's exact test, 1-sided, P = 0.018) and there was no significant difference between group A and group C (Fisher's exact test, 1-sided, P = 0.215). The activity of serum glutathione peroxidase of group A was marked higher than that of group B (adjusted t' test, 1-sided, t' = 6.474, P < 0.01). And the difference of activity of serum glutathione peroxidase between group A and group C was not significantly (adjusted t' test, 2-sided, t' = 1.920, P > 0.05).

Conclusion: The results suggested that vitamin E and coenzyme Q10 could improve the ability of free radicals cleaning and protect the mitochondrial DNA from 4834 bp deletion mutation.