Association between injury severity and amyloid β protein levels in serum and cerebrospinal fluid in rats with traumatic spinal cord injury.

The aim of the present study was to determine whether amyloid-β (Aβ) protein could be detected in the serum and cerebrospinal fluid (CSF) of rats with traumatic spinal cord injury (SCI) and whether Aβ protein levels in serum and CSF correlated with the injury severity. A total of 140 adult female Sprague‑Dawley rats were randomly divided into four groups: Sham, mild injury, moderate injury and severe injury. Serum and CSF samples were collected at 12 h, 1, 3, 7, 14, 21 and 28 days post‑injury. ELISA analysis for serum and CSF Aβ protein was performed. Locomotor function of all animals was assessed using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Following SCI, the protein levels of Aβ in serum and CSF samples from SCI groups significantly increased from 12 h (P<0.05) and peaked 3 days after injury. A significant increase of Aβ levels in serum and CSF in the severe SCI group was also observed at 28 days after injury (P<0.05). At 28 days after injury the protein levels of Aβ in serum and CSF were significantly correlated with the severity of injury (serum, R2=‑0.806, P<0.01; CSF, R2=‑0.694, P<0.01). A significant correlation between Aβ protein level in serum and CSF and neurological deficits (BBB score) was also observed (P<0.01). The protein level of Aβ in serum and CSF was severity and time‑dependent during the acute phase in rats with traumatic SCI. Monitoring the level of Aβ protein in serum may improve the evaluation of SCI severity and the neuron functional status following SCI.