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