P123. Ginkgo biloba extract EGb 761 improves vestibular compensation after unilateral labyrinthectomy in the rat and modulates hippocampal and cerebellar networks

Publication date: August 2018

Source: Clinical Neurophysiology, Volume 129, Issue 8

Author(s): A. Zwergal, M. Lindner, C. Branner, A. Krämer, L. Vomacka, A. Gosewisch, S. Ziegler, P. Bartenstein, M. Dieterich

Aim

Investigation of the efficacy and mode of action of the Ginkgo biloba extract EGb 761 in a rat model of unilateral labyrinthectomy (UL).

Methods

24 SD rats were included in the study and underwent a left-sided UL by transtympanic injection of bupivacaine/p-arsanilic acid. 8 rats each were randomized into groups receiving either control food only (Ctrl./Ctrl.); or control food prior to UL and EGb 761 supplemented food 15 after UL (Ctrl./EGb 761); or EGb 761 supplemented food 6 weeks prior and 15 days after UL (EGb 761/EGb 761). Vestibular behavioural testing including clinical scoring for nystagmus and postural imbalance as well as semi-automated analysis of locomotion in the open field was done on days 1, 2, 3, 5, 7, and 15 after UL. In addition, sequential whole-brain [18F]-FDG-μPET was performed before and on days 1, 3, 7, 15 after UL to measure cerebral glucose metabolism over time.

Results

After UL all animals exhibited severe signs of vestibular imbalance. A significantly stronger amelioration of nystagmus and postural imbalance scores was identified on days 1, 3, 5, 7 after UL in the EGb 761/EGb 761 group compared to the Ctrl./Ctrl. group (p < 0.05). Accordingly, locomotion speed in the open field was higher on day 7 in the EGb 761/EGb 761 group (p < 0.05). Improvement of symptoms was, to a lesser extent, also found when comparing the Ctrl./EGb 761 and Ctrl./Ctrl. group (reduced nystagmus score on days 1, 2, 5 and postural score at days 1, 5, 7 after UL). Measurements of the regional cerebral glucose metabolism (rCGM) by serial μPET revealed a gradual increase of rCGM in the hippocampal formation and decrease in the cerebellum in the EGb 761/EGb 761 > Ctrl./EGb 761 > Ctrl./Ctrl. group on days 1, 3, 15 after UL (p < 0.005).

Conclusion

EGb 761 improves central vestibular compensation in rats after unilateral inner ear damage compared to control treatment and modulates cerebral plasticity in hippocampal and cerebellar networks.

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