Aldehyde dehydrogenase 2 overexpression inhibits neuronal apoptosis after spinal cord ischemia/reperfusion injury

Abstract

Aldehyde dehydrogenase 2 (ALDH₂) is an important factor in inhibiting oxidative stress and has been shown to protect against renal ischemia/reperfusion injury. Therefore, we hypothesized that ALDH₂ could reduce spinal cord ischemia/reperfusion injury. Spinal cord ischemia/reperfusion injury was induced in rats using the modified Zivin's method of clamping the abdominal aorta. After successful model establishment, the agonist group was administered a daily consumption of 2.5% alcohol. At 7 days post-surgery, the Basso, Beattie, and Bresnahan score significantly increased in the agonist group compared with the spinal cord ischemia/reperfusion injury group. ALDH₂ expression also significantly increased and the number of apoptotic cells significantly decreased in the agonist group than in the spinal cord ischemia/reperfusion injury group. Correlation analysis revealed that ALDH₂ expression negatively correlated with the percentage of TUNEL-positive cells (r = -0.485, P < 0.01). In summary, increased ALDH₂ expression protected the rat spinal cord against ischemia/reperfusion injury by inhibiting apoptosis.

Keywords: alcohol; aldehyde dehydrogenase 2; apoptosis; nerve regeneration; neural regeneration; oxidative stress; spinal cord ischemia/reperfusion injury; terminal deoxynucleotidyl transferase dUTP nick-end labeling.

Figure 1

BBB scores in rats at 7 days after surgery. *P < 0.05, vs. sham group, #P < 0.05, vs. I/R group (mean ± SD, n = 10, one-way analysis of variance and Student-Newman-Keuls test). BBB: Basso, Beattie, and Bresnahan; I/R: ischemia/reperfusion.

Figure 2

Aldehyde dehydrogenase 2 overexpression affected histomorphology in rats with spinal cord ischemia/reperfusion injury (hematoxylin-eosin staining, ×200). Sham group: Normal spinal cord tissues; I/R group: serious damage; agonist group: mild damage. Arrows refer to injured cells. I/R: Ischemia/reperfusion.

Figure 3

Protein expression in the spinal cord of ALDH₂ in the sham, I/R, and agonist groups (western blot assay). Protein expression of ALDH₂ in the agonist group significantly increased compared with the I/R group. *P < 0.05, vs. sham group, #P < 0.05, vs. I/R group (mean ± SD, n = 10, one-way analysis of variance and Student-Newman-Keuls test). ALDH₂: Aldehyde dehydrogenase 2; I/R: ischemia/reperfusion; GAPDH: glyceraldehyde 3-phosphate dehydrogenase.

Figure 4

ALDH₂ overexpression affected apoptosis in rats with spinal cord ischemia/reperfusion injury (TUNEL assay, × 400). Sham group: Few TUNEL-positive cells; I/R group: many TUNEL-positive cells (arrows) compared with the agonist group. *P < 0.05, vs. sham group; #P < 0.05, vs. I/R group (mean ± SD, n = 10, one-way analysis of variance and Student-Newman-Keuls test). ALDH₂: Aldehyde dehydrogenase 2; I/R: ischemia/reperfusion; TUNEL: terminal deoxynucleotidyl transferase dUTP nick-end labeling.