Blue dye reduces secondary damage in spinal cord injury

Release date: 05-Nov-2009

Organisation: University of Rochester Medical Center

Researchers based at the University of Rochester Medical Center in New York State have shown a blue dye called brilliant blue G (BBG) reduces secondary damage in a rat model of spinal cord injury (SCI).

The team led by Professor Maiken Nedergaard, administered BBG intravenously 10-15 minutes after injury then once daily for the next two days. They monitored recovery of the animals over the next six weeks.

The group found BBG significantly improved motor recovery, the BBG-treated rats regaining locomotor function better and faster than control animals.

The researchers also found BBG treatment reduced the amount of spinal cord tissue loss and lowered the local inflammatory response. BBG also protected spinal cord neurons from overstimulation and hence neuronal death.

BBG is a derivative of a commonly used blue food colour (FD&C blue No.1) and has low toxicity, although the rats’ skin and eyes temporarily turned blue, for up to one week.

The research follows on from previously published work by the group in 2004. They found traumatised spinal cord tissue released excessive amounts of a molecule called ATP. ATP causes overstimulation and cell death by activation of receptors on spinal cord neurons known as P2X7 receptors.

Thus the scientists set out to find a clinically relevant strategy to help prevent secondary injury and neural death by blocking the P2X7 receptors. BBG does just this: it blocks the action of ATP on the P2X7 receptors, thus preventing the excessive activity and subsequent neuronal death.

The low toxicity of BBG and its ease of entry into the brain and spinal cord suggest that it might be useful clinically. The researchers hope early BBG treatment in combination with other anti-inflammatory compounds could help improve recovery from SCI in the future.

Source: Peng, et al. (2009) Systemic administration of an antagonist of the ATP-sensitive receptor P2X7 improves recovery after spinal cord injury. Proceedings of the National Academy of Sciences, 106(30); 12489-12493.

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