Curcumin promotes functional recovery and inhibits neuronal apoptosis after spinal cord injury through the modulation of autophagy

Abstract

Objective: The study was aimed to investigate whether the neuroprotective role of curcumin is associated with regulation of autophagy.

Methods: Rat spinal cord injury (SCI) models were established according to Allen’s weight-drop trauma method. Curcumin was administered 30 min after the contusion and continued weekly. At 3, 7, 14, 21, and 28 days after SCI, functional recovery was evaluated using the Basso, Beattie and Bresnahan (BBB) scoring and the oblique plate test, following which, spinal cord tissues were obtained. Histological changes and apoptosis were then measured with H&E staining and TUNEL assay. Glia activation, inflammatory infiltration, inflammatory factor release, and myelination were observed through immunohistochemical (IHC) staining and ELISA. Autophagy and Akt activation were detected by western blotting. After autophagy was inhibited by injection of chloroquine, TUNEL, inflammatory factor release, myelin basic protein (MBP) IHC staining and functional recovery evaluation were performed again.

Results: Curcumin treatment promoted functional recovery after SCI and reduced neuron apoptosis, improved spinal cord integrity, recovery, and re-myelination, and suppressed the inflammatory response. Autophagy was enhanced and Akt/mTOR pathway was inhibited by curcumin. Autophagy inhibition partially eliminated the protective effect of curcumin on SCI.

Conclusion: Curcumin may exert its therapeutic effect on SCI through the enhancement of autophagy, in which, inhibition of the Akt/mTOR signaling pathway may be also involved.

Keywords:

• Curcumin
• Spinal cord injury
• Autophagy
• Akt
• mTOR

Additional information

Funding

This study was supported by the National Natural Science Foundation of China (NSFC, Grant No.: 81860240), the Development Program of Kunming University of Science and Technology (sponsored by Yunnan Provincial Department of Science and Technology; Grant No.: KKSY201560051), and Yunnan Provincial Science and Technology Department-Kunming Medical University Joint Special Project (sponsored by Yunnan Provincial Department of Science and Technology; Grant No.: 2015FB095).