The Effect Of Radioactive ¹²⁵I Seeds On Facial Nerve Of Rabbits

Objectives:The impact of radioactive 125I seed implant into rabbit facial nerve was investigated, which provide a certain basis for the treatment of parotid gland 125I particles.Methods:Shell particles was implanted in big ears of New Zealand white rabbit around the right side of the facial nerve, there is also one and two radioactive 125I seed at the same time,. (1) observing the experimental side of the beard rabbits, mouth changes at 7d,14d,30d,60d; (2) Animals were anesthetized with pentobarbital sodium (lml/kg) by ear vein injection, the author will test the experimental side of the row neural electrophysiological and observe the emergence of self-generation and conduction velocity changes; (3) the author will take the appropriate facial for pathological testing and observe changes of the nerve ultra structure by the TEM.Results:(1) We observed that the experimental animals which were not there mustache drooping, crooked mouth symptoms such as facial paralysis. (2) Nerve electrophysiology:shell particle groups were detected in 7,14,30,60 days no spontaneous potential, and can be induced by stimulating action potentials, and there was no significant difference with conduction velocity of normal group; one and two granular sub-group were not detected at day 7,14,30,60 spontaneous potential, both of which a group of slower conduction velocity of 60 days, there had been corresponding conduction velocity phenomenon in 2 groups after 14 days, particularly obvious in the 60 days. (3) Histopathology:shell particle group structure and facial nerve pathology were similar to the normal structure of the facial nerve; one and two particles group after 125I seed implanted, the myelin sheath and axonal pathology appeared appropriately, with the increasing in the number of days, facial nerve injury also had become increasing trend. (4) Electron microscope:shell particle group, we saw individual nerve myelin in vacuolar changes, there is no abnormal changes in the axon. A particle group of nerve fiber has degenerated, and parts of lamellar structure of myelin were separated. Two particle group of myelin were damaged heavier, parts of the axon disappeared and a new nerve fibers was fund at the same time.Conclusions; Rabbit facial nerve was observed by nerve electrophysiological testing, tissue pathology, ultra structure, which indicatives that particles of radioactive 125I has a certain injury to facial nerve,the greater dose and the growth of time, the degree of facial nerve injury is heavier, But the damage did not result in facial paralysis, at the same time, over time, particle did gradually decreases and the corresponding region ultra structural damage of nerve fibers occurred in newborn, which suggested that instructions can still be recycled, its long-term effects of further investigation was needed.