Acute and delayed implantation of positively charged 2-hydroxyethyl methacrylate scaffolds in spinal cord injury in the rat.
OBJECTIVE
Hydrogels are nontoxic, chemically inert synthetic polymers with a high water content and large surface area that provide mechanical support for cells and axons when implanted into spinal cord tissue.


METHODS
Macroporous hydrogels based on 2-hydroxyethyl methacrylate (HEMA) were prepared by radical copolymerization of monomers in the presence of fractionated NaCl particles. Male Wistar rats underwent complete spinal cord transection at the T-9 level. To bridge the lesion, positively charged HEMA hydrogels were implanted either immediately or 1 week after spinal cord transection; control animals were left untreated. Histological evaluation was performed 3 months after spinal cord transection to measure the volume of the pseudocyst cavities and the ingrowth of tissue elements into the hydrogels.


RESULTS
The hydrogel implants adhered well to the spinal cord tissue. Histological evaluation showed ingrowth of connective tissue elements, blood vessels, neurofilaments, and Schwann cells into the hydrogels. Morphometric analysis of lesions showed a statistically significant reduction in pseudocyst volume in the treated animals compared with controls and in the delayed treatment group compared with the immediate treatment group (p < 0.001 and p < 0.05, respectively).


CONCLUSIONS
Positively charged HEMA hydrogels can bridge a posttraumatic spinal cord cavity and provide a scaffold for the ingrowth of regenerating axons. The results indicate that delayed implantation can be more effective than immediate reconstructive surgery.
Hejcl
Ales
A
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Czech Republic. ales.hejcl@mnul.cz
Urdzikova
Lucie
L
Sedy
Jiri
J
Lesny
Petr
P
Pradny
Martin
M
Michalek
Jiri
J
Burian
Martin
M
Hajek
Milan
M
Zamecnik
Josef
J
Jendelova
Pavla
P
Sykova
Eva
E
D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use*; D003238:Connective Tissue / Q000473:pathology; D003560:Cysts / Q000473:pathology; D004195:Disease Models, Animal; D048091:Guided Tissue Regeneration; D020100:Hydrogels / Q000737:chemistry / Q000627:therapeutic use*; D008297:Male; D008689:Methacrylates / Q000737:chemistry / Q000627:therapeutic use*; D009416:Nerve Regeneration / Q000502:physiology; D009454:Neurofibrils / Q000648:ultrastructure; D010264:Paraplegia / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000473:pathology; D013116:Spinal Cord / Q000098:blood supply / Q000473:pathology; D013119:Spinal Cord Injuries / Q000601:surgery*; D013997:Time Factors; D054457:Tissue Scaffolds; D014945:Wound Healing / Q000502:physiology
C120889:2-(trimethylammonio)ethyl methacrylate; D001672:Biocompatible Materials; D020100:Hydrogels; D008689:Methacrylates; C005044:hydroxyethyl methacrylate