Monitoring the protective effects of minocycline treatment with radiolabeled annexin V in an experimental model of focal cerebral ischemia.
Minocycline is an antibiotic now recognized to have antiapoptotic and antiinflammatory properties. Because of these properties, minocycline may be of benefit in reducing neuronal apoptosis from ischemia and subsequent postischemic inflammation if administered soon after a stroke. We now explore the feasibility of using (99m)Tc-annexin V, an in vivo marker of apoptosis, with SPECT to monitor the antiapoptotic effects of minocycline therapy.


METHODS
CB6/F1 adult male mice underwent unilateral distal middle cerebral artery occlusion (dMCA) occlusion and were imaged and sacrificed at 1, 3, 7, or 30 d after injury. Animals were given minocycline (or vehicle) 30 min and 12 h after dMCA occlusion and then given 22.5 mg/kg twice daily for up to 7 d. Before imaging, behavioral tests were performed to evaluate the neurologic function. After imaging, brains were collected for histology and assessed for the degree of apoptosis and microglial activation.


RESULTS
(99m)Tc-Annexin V uptake in injured hemispheres was significantly decreased 2- to 3-fold by minocycline at all time points. Minocyline reduced infarct size as seen histologically and improved behavioral indices as late as 30 d. Infarct volume as seen histologically correlated with radiolabeled annexin V uptake seen by SPECT. In situ fluorescent microscopy demonstrated that annexin V bound primarily to neurons at 1 and 3 d, with a shift toward microglia by 7 and 30 d.


CONCLUSIONS
We found that minocycline significantly reduces neuronal apoptosis and infarct size and improves neurologic outcome in mice after acute focal cortical ischemia.
Tang
Xian Nan
XN
Department of Neurology, University of California San Francisco, San Francisco, CA 94121, USA.
Wang
Qing
Q
Koike
Maya A
MA
Cheng
Danye
D
Goris
Michael L
ML
Blankenberg
Francis G
FG
Yenari
Midori A
MA
D000818:Animals; D017304:Annexin A5 / Q000737:chemistry; D017209:Apoptosis; D006834:Hydrazines / Q000737:chemistry; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000517:prevention & control*; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000517:prevention & control*; D008297:Male; D051379:Mice; D017628:Microglia / Q000000981:diagnostic imaging; D008911:Minocycline / Q000627:therapeutic use*; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D009539:Nicotinic Acids / Q000737:chemistry; D015609:Organotechnetium Compounds / Q000737:chemistry; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon
C120392:6-hydrazinopyridine-3-carboxylic acid; D017304:Annexin A5; D006834:Hydrazines; D018696:Neuroprotective Agents; D009539:Nicotinic Acids; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D008911:Minocycline