ABSTRACT
OBJECTIVE: To observe the effect of sustained-release vehicle-Poloxamer 407 on the function and morphology of the cochlear after perfusion in round window. METHODS: The right ears of 16 guinea pigs as experimental group were perfusion with 20% Poloxamer 407 solusion 100 microl in round window, the left ears as control group with normal saline. Another 4 animals without treatment were in negative control group. Auditory function was investigated before and immediate, 7, 14, 28, 49 days after perfusion, and the cochlear basilar membranes were stained by silver nitrate after ABR examinations. The stained basilar membranes were examined under light microscopy. RESULTS: The ABR threshold to filtered clicks were elevated after perfusion, and were recovered to normal at 49 days after perfusion. The morphology of cochlear hair cells were not significantly damaged after perfusion. CONCLUSION: Poloxamer 407 after topical perfusion in round window can cause temporary changes on auditory function of inner ear, but no inreversible damage on function and morphology of cochlear. Therefore, Polomamer 407 can be used as sustained-release vehicle in middle and inner ear diseases.
Subject(s)
Cochlea/drug effects , Poloxamer/pharmacology , Round Window, Ear/drug effects , Animals , Auditory Threshold/drug effects , Cochlea/cytology , Cochlea/physiology , Guinea Pigs , Round Window, Ear/cytology , Round Window, Ear/physiologyABSTRACT
OBJECTIVE: To observe the biodegradation and absorption of poloxamer 407 in vivo, and the effect of poloxamer 407 on the middle ear and inner ear after regional perfusion in guinea pigs. METHODS: The right ears of 10 guinea pigs as experimental group were perfused with 20% poloxamer 407 in situ gel 100 microl in round window niche, with the left ears as control group with normal saline. Another two animals without treatment were in negative control group. Auditory function was investigated before and 3, 7, 14, 28, 49 days after perfusion, and the histology of bulles after auditory brainstem response (ABR) each examination were examined by means of serial section after paraffin imbedding. RESULTS: The poloxamer gel was almost biodegraded and discharged 49 days after perfusion, only few gel remained in the middle ear cavity under light microscope. The ABR threshold to filtered clicks was elevated after perfusion with poloxamer 407, and was recovered to normal at 49 days after perfusion. The morphology of the mucosa of middle ear cavity, round window membrane, Corti's and vestibular organs were not significantly damaged after poloxamer 407 perfusion. CONCLUSIONS: Poloxamer 407 can be biodagraded in vivo or discharged via eustachian tube, and causes no inflammation on the middle ear cavity. There are temporary changes on auditory function of inner ear after topical perfusion with poloxamer 407 in round window can cause, but no irreversible damage on function and morphology of cochlear and vestibular organs.
Subject(s)
Ear, Inner/drug effects , Ear, Middle/drug effects , Poloxamer/pharmacology , Animals , Guinea Pigs , Poloxamer/administration & dosageABSTRACT
OBJECTIVE: To establish an animal model of Bell palsy induced by type I herpes simplex virus (HSV-1) infection and to assess the role and site of HSV-1 in the pathogenesis of facial paralysis. METHODS: Fifty-three female Balb/c mice four-week-old weighted 16-18 g were studied. After scratching the surface of bilateral auricles with a 26-gauge needle, 25 microL HSV-1 with a titer of 6. 7 x 10(7) PFU/ml was inoculated into the right auricle, and the same volume of PBS was placed in the left. As a control, PBS was placed on the bilateral auricles of 4 mice. The HSV-1 DNA in bilateral facial nerve, bilateral brainstem, bilateral trigeminal carrier ganglion, bilateral brain, and blood at different stage was examined with polymerase chain reaction analysis. RESULTS: Thirty-seven animals (75.51%) appeared different degree facial paralysis among the 49 inoculated animals. Fourteen facial paralysis (37.84%) were on the right, 3 (8.11%) on the left, and 20 (54.05%) on the bilateral side. Six animals with facial palsy were recovered during 3-13 days, the average recovery time was 7.83 days. CONCLUSIONS: The existence of HSV-1 in the brainstem and the cerebral cortex is significant for facial paralysis.
