Matrix metalloproteinase-12 leads to elastin degradation in BALB/c mice with eosinophilic meningitis caused by Angiostrongylus cantonensis

The rat lugworm Angiostrongylus cantonensis can cause eosinophilic meningitis. The purpose of this study was to determine whether matrix metalloproteinase (MMP)-12 and its substrate elastin participate in this inflammatory response. We showed that the MMP-12/tissue inhibitor of metalloproteinase-1 ratio was significantly increased in the CSF of A. cantonensis-infected mice from day 10 p.i., and reached high levels on days 20 and 25 p.i. MMP-12 production was correlated with elastin degradation, eosinophil count, blood-CSF barrier permeability and pathological changes in the subarachnoid space. Also, MMP-12 might contribute to elastin degradation in the meningeal vessel of the subarachnoid space. Simultaneous administration of albendazole and doxycycline significantly reduced the levels of MMP-12, elastin and Evans blue in mice with meningitis. These results imply that MMP-12 contributes to the elastin degradation that occurs in angiostrongyliasis meningitis, and doxycycline can reverse related inflammatory events by inhibition of MMP-12.