Background: Apoptosis plays an important role in central neural diseases and trauma. B-cell lymphoma/Leukemia-2 (Bcl-2) can inhibit apoptosis in a wide variety of cells including neurons. In this experiment, by studying Bcl-2 over-expression transgenic (TG) mice subjected to spinal cord injury (SCI), we investigated whether Bcl-2 could reduce posttraumatic neuronal apoptosis, reduce the range of damage, and improve the behavioral functional recovery after contusive SCI.
Methods: Nine Bcl-2 TG mice and nine control mice were subjected to SCI of moderate severity at T10, with the use of weight dropping (WD) method (impact force 2.5×3.0 g/cm). At times up to 1 day, 7 days and 14 days after SCI, functional deficits were evaluated with Basso, Beattie, and Bresnahan (BBB) scales, and apoptosis of neurons was investigated by using the TUNEL method. Another three control mice only underwent lamina opening, but were not subjected to SCI, to provide blank comparison.
Results: The mean functional scores for the control mice (5.05 ±0.35) were lower than those for the Bcl-2 TG mice (5.45 ±0.15), although the unpaired T-test revealed no significant difference (P=0.67). On the other hand, the number of TUNEL positive neurons and integrated option density (IOD) scores for the Bcl-2 TG mice were both significantly lower than those for the control mice (P<0.05).
Conclusions: This experiment suggests that overexpression of Bcl-2 may suppress neuronal apoptosis after SCI. Bcl-2 may be an important factor within the central nervous system that can relieve the damage after trauma.
Keywords: Apoptosis of neurons; Bcl-2; Spinal cord injury; Transgenic mouse; Weight dropping.