Photomechanical wave-driven delivery of siRNAs targeting intermediate filament proteins promotes functional recovery after spinal cord injury in rats

• Published in: PloS one Vol. 7; no. 12; p. e51744
• Main Authors: Ando, Takahiro, Sato, Shunichi, Toyooka, Terushige, Kobayashi, Hiroaki, Nawashiro, Hiroshi, Ashida, Hiroshi, Obara, Minoru
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.12.2012; Public Library of Science (PLoS)
• Subjects: Animals; Astrocytes; Biology; Brain research; Disease Models, Animal; Electrical engineering; Engineering; Female; Fluorescence; Fluorescent Dyes - chemistry; Gene expression; Gene Transfer Techniques; Glial cells; Glial fibrillary acidic protein; Glial Fibrillary Acidic Protein - genetics; Glial Fibrillary Acidic Protein - metabolism; Information science; Injuries; Intermediate filament proteins; Intermediate Filament Proteins - genetics; Intermediate Filament Proteins - metabolism; Lasers; Locomotives; Medicine; Membrane permeability; Neurosurgery; Permeability; Proteins; Rats; Recovery (Medical); Recovery of function; Regeneration; Restoration; RNA Interference; RNA, Small Interfering - chemistry; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Rodents; Scars; Semiconductor lasers; siRNA; Spinal cord; Spinal cord injuries; Spinal Cord Injuries - genetics; Spinal Cord Injuries - pathology; Spinal Cord Injuries - rehabilitation; Spinal cord injury; Staining and Labeling; Studies; Ultrasonic imaging; Vimentin; Vimentin - genetics; Vimentin - metabolism; YAG lasers
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0051744

The formation of glial scars after spinal cord injury (SCI) is one of the factors inhibiting axonal regeneration. Glial scars are mainly composed of reactive astrocytes overexpressing intermediate filament (IF) proteins such as glial fibrillary acidic protein (GFAP) and vimentin. In the current study, we delivered small interfering RNAs (siRNAs) targeting these IF proteins to SCI model rats using photomechanical waves (PMWs), and examined the restoration of motor function in the rats. PMWs are generated by irradiating a light-absorbing material with 532-nm nanosecond laser pulses from a Q-switched Nd:YAG laser. PMWs can site-selectively increase the permeability of the cell membrane for molecular delivery. Rat spinal cord was injured using a weight-drop device and the siRNA(s) solutions were intrathecally injected into the vicinity of the exposed SCI, to which PMWs were applied. We first confirmed the substantial uptake of fluorescence-labeled siRNA by deep glial cells; then we delivered siRNAs targeting GFAP and vimentin into the lesion. The treatment led to a significant improvement in locomotive function from five days post-injury in rats that underwent PMW-mediated siRNA delivery. This was attributable to the moderate silencing of the IF proteins and the subsequent decrease in the cavity area in the injured spinal tissue.