In addition to the MMP action Arron pointed out, that is similar to lipoic acid as NHE noted, here are some other broad "indicators" that minocycline may be quite neuroprotective.
From the Department of Neurobiology, University of Kuopio in Finland:
To date, minocycline has been demonstrated to have a benefical effect in a wide variety of models of neuropathological conditions, including brain and spinal cord trauma, hemorrhagic stroke, Parkinson’s disease (PD), multiple sclerosis (MS), ALS, Huntington’s disease (HD), Alzheimer’s disease (AD), neonatal hypoxia-ischemia, ototoxicity, glaucoma, HIV, encephalopathy, prion disease and pain. Phase III clinical trials of minocycline are in process for MS, ALS and PD.
Here's another abstract Minocycline for Short Term Neuroprotection
As a neuroprotective agent, the drug appears more effective than other treatment options. In addition to its high penetration of the blood-brain barrier, minocycline is a safe compound commonly used to treat chronic infections. Its several mechanisms of action in neuroprotection-antiinflammatory and antiapoptotic effects, and protease inhibition-make it a desirable candidate as therapy for acute neurologic injury, such as ischemic stroke. Minocycline is ready for clinical trials of acute neurologic injury.
Neuroprotection in Brain and Spinal Cord Trauma
Various experimental animal investigations suggest that potential therapeutic agents include estrogen, progesterone, minocycline, erythropoietin, and magnesium.
Notice I didn't emphasize estrogen and progesterone. In the absence of a definite "cause" of MS, I lean toward neuroprotection, but it would be really nice to know what's what. Let's hope someone has that on their research agenda.