This study aimed to investigate the effect of local and intraperitoneal administration of l-carnitine on the prevention of experimentally induced myringosclerosis, and to compare treatment efficiency.

Twenty-four Albino-Wistar rats (48 ears) were bilaterally myringotomised and divided randomly into four groups: group one received no treatment, group two received intraperitoneal l-carnitine, group three received local l-carnitine, and group four received both intraperitoneal and local l-carnitine. On the 15th day after treatment, tympanic membranes were harvested and evaluated histopathologically for myringosclerotic plaque formation, fibroblastic proliferation, tympanic membrane thickness and new vessel formation.

The group one tympanic membranes showed extensive thickness, and the incidence of myringosclerosis and fibroblast proliferation were greater than in groups two and four. There were statistically significant differences in tympanic membrane thickness between groups three and four, and in myringosclerosis incidence and fibroblast proliferation, comparing groups two, three and four.

Myringosclerosis development was significantly reduced in rats receiving myringotomy plus intraperitoneal l-carnitine. Intraperitoneal l-carnitine administration prevented fibroblastic proliferation and tympanic membrane thickening (both of which cause further tympanic membrane destruction), thus reducing myringotomy-associated morbidity. Local l-carnitine administration had limited effectiveness in this experimental setting.

This experimental study aimed to investigate the effects of vitamins E, B and C and l-carnitine in preventing cisplatin-induced ototoxicity.

Twenty-five adult, male, Wistar albino rats were randomly allocated to receive intraperitoneal cisplatin either alone or preceded by vitamins B, E or C or l-carnitine. Auditory brainstem response (i.e. hearing thresholds and wave I–IV intervals) and distortion product otoacoustic emissions (i.e. signal-to-noise ratios) were recorded before and 72 hours after cisplatin administration.

The following statistically significant differences were seen: control group pre- vs post-treatment wave I–IV interval values (p < 0.05); control vs vitamin E and B groups' I–IV interval values (p < 0.05); control vs other groups' hearing thresholds; vitamin E vs vitamin B and C and l-carnitine groups' hearing thresholds (p < 0.05); and vitamin B vs vitamin C and l-carnitine groups' hearing thresholds (p < 0.05). Statistically significant decreases were seen when comparing the initial and final signal-to-noise ratios in the control, vitamin B and l-carnitine groups (2000 and 3000 Hz; p < 0.01), and the initial and final signal-to-noise ratios in the control group (at 4000 Hz; p < 0.01).

Vitamins B, E and C and l-carnitine appear to reduce cisplatin-induced ototoxicity in rats. The use of such additional treatments to decrease cisplatin-induced ototoxicity in humans is still under discussion.