Study On The Changes Of Vestibular System Following Unilateral Labyrinthectomy And The Mechanisms Of Ginaton Enhancing Vestibular Compensation

1.Standard extract of Ginkgo Biloba enhancing static and dynamic syndromes compensation following UL in guinea pigsAfter UL, guinea pigs manifest SN, head lift and other static syndrome.Recovery of the static syndrome" s with and without standard extract of Ginkgo biloba following UL were observed. UL+EGb recovered faster than UL.Standard extract of Ginkgo biloba could enhance the compensation of static syndrome and SN recuperated faster and more completely than head tilt. The UL group's post-lesional nystagmus frequency didn't recover until the 90th d, while UL+EGb group return to normal 21 d post-lesion. In addition, the UL group's directional preponderance (DP) was abnormal 50d post- lesion, but lesion plus EGb's return to normal from the 7th d post-lesion. The recovery of DP was faster than nystagmus frequency Therefore Ginaton could enhance dynamic compensation. And bilateral equilibrium's recovery was faster than that of nystagmusfrequency2. The expression of GFAP in the MVN following different modes of peripheral vestibular lesions in guinea pigsU)GFAP staining enhancement can be induced in bilateral MVN following UL. However, that of the lesioned side is stronger than that of the unlesioned side The reaction became evident 10 h post-UL and was intense 20-40 h after lesion. Then it declined until 20 d, but still intenser than that of the control group If Ginaton is administered, the staining positive cells are less than that of the UL. But the significance of the reactive satrocytes in the vestibular compensation is still unknown. And Ginaton may play a role in sparing the EAA toxicity to some extent.It can be drawn that proliferation of astrocytes may to some extent serve as somewhat of protection for MVN(2)Gentamycin can induce the proliferation of astrocytes in the MVN. 20d after gentamycin administration, the proliferation reached its peak.The reaction is maily through the peripheral vestibular system because gentamycin cannot transpass the blood-brain barrier The proliferation of astrocytes after gentamycin administration may contribute to the neuronal protection for glial cells play an important role in the regulation of glutamic acid and aspartate.3.The influence of Ginaton on the Scarpa's ganglion after ULUL and vestibualr neuroectomy was applied to remove the primary vestibular afferent After UL, Scarpa's ganglion were spared Therfore, it may still exert some effects on the vestibular system. The findings showed that lOhr after UL, the ganglion had no evident change under microscope But the change became severe at 20hr and aggravated gradually thereafter: The change in UL+EGb group was lessen than UL. It manifested that Ginaton had the effect of ganglion protection and the better way to remove the primary afferent was through neurotomy.In addition,Ginaton also had the function of suppression of ganglion apotosis4. The influence of Ginaton on expression of synaptophysin in the MVN after ULSynaptophysin is a major membrane integrated protein at the synaptic follicles. It acts as a sensitive marker for synaptic intensity at molecular level hi this expenment,synaptophysin was used to evaluate the change of synaptic density post-UL lOhr post UL, the immunoreactive intensity of synaptophysin declined in the lesioned side.lt increased slightly at 20d;and the intensity recovered significantly at 90d post UL, but still lower than that in control. In the UL+EGb group, the intensity of synaptophysin was stronger than that in the UL at 1 Oh and 20d But at 90 d, the UL+EGb was intense than UL and had no significant difference compared with the control. It suggested that in UL+EGb group the synaptic density recovered quickly. It underlied that vestibular compensation and the enhancing effect of Ginaton is involved in the structural resconstruction in the MVN.5.The influence of standard extract of Ginkgo biloba on the MVN infrastructure following UL in guinea pigsFollowing UL, EGb can promote the recovery of the post-rotational nystagmus. On the aspect of ultrastruc...