Precise Delivery Into Chronic Spinal Cord Injury Syringomyelic Cysts with Magnetic Nanoparticles MRI Visualization.
BACKGROUND
Traumatic spinal cord injury (SCI) often results in the deficiency of glia and neurons in cystic cavities. These syringomyelic cysts can prevent axonal regeneration and sprouting. Details of the mechanism of syringomyelic cyst formation are unknown and an effective treatment for overcoming syringomyelic cysts is not available.


METHODS
Ten adult female Wistar rats underwent contusion SCI modeling resulting in syringomyelic cyst formation. A novel method for locating the cysts was developed and employed. MRI safe silver needles were inserted through the erector spinae of anesthetized rats to create a stable reference point. MRI images of the rodent spine were taken with the needles in situ. This information was used to accurately locate the cyst and determine the 3-dimensional entry point coordinates for nanoparticle delivery. Nanoparticles were injected into the cyst during a primary injection of 8 ul and a secondary injection of 8 ul, to prove the procedure can be accurately repeated.


RESULTS
None of the rats died intra- or post-operatively. The syringomyelic cysts were accurately located with the 3-dimensional entry point coordinates. After nanoparticle delivery twice into each rat, the visualized syringomyelic cyst volume significantly decreased from 5.71±0.21 mm3 to 3.23±0.364 mm3 and to 1.48±0.722 mm3.


CONCLUSIONS
The present study describes a novel strategy for precise nanoparticle delivery into a syringomyelic cyst, using measurements obtained from MRI images. This strategy may aid in developing a new method for studying chronic spinal cord injury and a novel treatment for syringomyelic cysts.
Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China (mainland).
Chao
C
Zhang
Department of Basic and Applied Neurobiology, Federal Medical Research Center for Psychiatry and Narcology, Moscow, Russian Federation.
Anna Y
AY
Morozova
Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation.
Maxim A
MA
Abakumov
Department of Orthopedics, Pirogov Russian National Research Medical University, Moscow, Russian Federation.
Ilya L
IL
Gubsky
0.
Patricia
P
Douglas
Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China (mainland).
Shiqing
S
Feng
Center for Biomedical Technologies, Federal Research and Clinical Center for Specialized Types of Medical Assistance and Medical Technologies of The Federal Medical Biological Agency, Moscow, Russian Federation.
Andrey S
AS
Bryukhovetskiy
Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation.
Vladimir P
VP
Chekhonin
D000818:Animals; D003560:Cysts / Q000473:pathology*; D016503:Drug Delivery Systems; D005260:Female; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D009339:Needles; D051381:Rats; D017208:Rats, Wistar; D012834:Silver / Q000737:chemistry; D013119:Spinal Cord Injuries / Q000473:pathology*; D013595:Syringomyelia / Q000473:pathology*
D058185:Magnetite Nanoparticles; D012834:Silver