Effects of PEG minocycline-liposomes on the expression of matrix metalloproteinase (MMP)-9 in splenocytes and CNS-infiltrating leukocytes.

<p>The expression levels of MMP-9 were significantly down-regulated on day 20 after active induction of experimental autoimmune encephalomyelitis (EAE) in splenocytes of mice following treatment with daily intraperitoneal (i.p.) injections of minocycline, and after intravenous (i.v.) injections of PEG minocycline-liposomes every 5 days compared to experimental animals that received no treatment, that were treated with i.v. injections of empty PEG-liposome every five days, or with minocycline i.p. injections every five days, as shown by ELISA (A). The proteolytic activity of MMP-9 measured by zymography was also significantly diminished in mice treated daily with i.p. injections of minocycline and i.v. injections of PEG minocycline-liposomes every five days (B). MMP-9 protein expression in CNS mononuclear cells was not found to be significantly different between experimental groups (C).