The neuroprotective effects of z-DEVD.fmk, a caspase-3 inhibitor, on traumatic spinal cord injury in rats.
BACKGROUND
Apoptosis is one of the most important forms of cell death seen in a variety of physiological and pathological conditions, including traumatic injuries. This type of cell death occurs via mediators known as caspases. Previous studies have investigated the roles that apoptosis and different caspases play in the pathogenesis of secondary damage after spinal cord injury (SCI). The aim of this research was to assess the neuroprotective effect of z-DEVD.fmk, a caspase-3 inhibitor, in a rat model of SCI.


METHODS
Forty-five Wistar albino rats were studied in 3 groups of 15 animals: sham-operated control animals (group 1); trauma-only control animals (group 2); and rats subjected to trauma + z-DEVD.fmk treatment (group 3). Spinal cord injury was produced at the thoracic level using the weight-drop technique. Responses to injury and the efficacy of z-DEVD.fmk were assessed by light microscopy and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining in cord tissues collected at 4 and 24 hours posttrauma. Five rats from each group were used to assess functional recovery at 7 days after SCI. The functional evaluations were done using the inclined-plane technique and a modified Tarlov motor grading scale.


RESULTS
At 4 hours postinjury, the mean apoptotic index in groups 1, 2, and 3 was 0, 33.01+/-6.62, and 16.40+/-4.91, respectively. The group 3 count was significantly lower than the group 2 count (P<.01). At 24 hours postinjury, light microscopic examination of group 2 tissues showed widespread hemorrhage, necrosis, polymorphonuclear leukocyte infiltration, and vascular thrombi. The group 3 tissues showed similar features. The prominent findings in group 2 were hemorrhage and necrosis, whereas the prominent findings in group 3 were focal hemorrhage and leukocyte infiltration. The mean inclined-plane angles in groups 1, 2, and 3 were 64.5 degrees+/-1.0 degrees, 41.5 degrees+/-1.3 degrees, and 47 degrees+/-2.0 degrees, respectively. Motor scale results in all groups showed a similar trend.


CONCLUSIONS
Local application of z-DEVD.fmk after SCI in rats reduces secondary tissue injury and helps preserve motor function. These effects can be explained by inhibition of apoptotic death in all cell types in the spinal cord.
Barut
Seref
S
Neurosurgery Clinic, Taksim Education and Research Hospital, Istanbul, Turkey, 34144.
Unlü
Yusuf Atilla
YA
Karaoğlan
Alper
A
Tunçdemir
Matem
M
Dağistanli
Fatma Kaya
FK
Oztürk
Melek
M
Colak
Ahmet
A
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors / Q000627:therapeutic use*; D004195:Disease Models, Animal; D020287:In Situ Nick-End Labeling; D008297:Male; D009043:Motor Activity; D009842:Oligopeptides / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology
D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D009842:Oligopeptides; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C505410:Casp3 protein, rat; D053148:Caspase 3