Attenuation of Pain After Spinal Injury May be Possible

Microglia spinal support nerves become activated after nerve and spinal injury an greatly potential the pain. Animal experiments show minocycline, a tetracycline antibiotic known to inhibit microglia, can reduce post spinal pain in animal subjects.

Previously I have discussed how microglia are important in causing chronic pain:
Microglia Key to Neuropathic Pain link here

I also discussed how minocycline prevents neuropathic pain after nerve injury in animals by inhibiting microglia:
Ounce of Prevention is a Pound of Cure For Neuropathic Pain link here

Now further benefit shown here:

J Rehabil Res Dev. 2009;46(1):123-33.
Early microglial inhibition preemptively mitigates chronic pain development after experimental spinal cord injury.
Tan AM, Zhao P, Waxman SG, Hains BC abstract here

• Rats – thoracic level spinal injury
• minocycline for 5 days post injury
• This reduced microglia activation
• There was both behavioural and electrophysiological evidence of reduced pain

Comment – For oral use, doxycycline 100 mg twice daily could be used instead and is safer than minocycline, which can cause lupus and liver damage. However, a five day course would be less of a concern. One of the new concepts in chronic pain is that of “pain memory” – a seed is set in memory that the chronic pain can grow on. It seens to me the spinal cord micorglia activation is part of that. I can see in the future use of microglia inhibitors such as these tetracycline given prior to surgery and after spinal cord injuries. I wonder if whiplash would fall in there somewhere as well…

Addendum:

Use of TNF inhibitor, Entanercept, resulted in markd deminution of mechanical allodynia in animal models post spinal cord injury:

Eur J Pain. 2009 Aug;13(7):673-81. Epub 2008 Oct 11.

Effects of Etanercept and Minocycline in a rat model of spinal cord injury.

Marchand F, Tsantoulas C, Singh D, Grist J, Clark AK, Bradbury EJ, McMahon SB.

abstract here

I wonder how long it will take for these treatments to become used in humans?

Any comments?