Anti-inflammatory effects of PJ34, a poly(ADP-ribose) polymerase inhibitor, in transient focal cerebral ischemia in mice.

BACKGROUND AND PURPOSE: Activation of poly(ADP-ribose) polymerase (PARP) is deleterious during cerebral ischemia. We assessed the influence of PARP activation induced by cerebral ischemia on the synthesis of proinflammatory mediators including the cytokines, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) and the adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1). EXPERIMENTAL APPROACH: Ischemia was induced by intravascular occlusion of the left middle cerebral artery for 1 h in male Swiss mice anaesthetized with ketamine and xylazine. The PARP inhibitor PJ34 (1.25-25 mg kg(-1)) was administered intraperitoneally 15 min before and 4 hours after, the onset of ischemia. Animals were killed 6 h or 24 h after ischemia and cerebral tissue removed for analysis. KEY RESULTS: Ischemia increased TNF-alpha protein in cerebral tissue at 6 and 24 h after ischemia. All doses of PJ34 blocked the increase in TNF-alpha at 6 h and 25 mg kg(-1) PJ34 had a sustained effect for up to 24 h. Quantitative real time polymerase chain reaction showed that PJ34 (25 mg kg(-1)) reduced the increase in TNF-alpha mRNA by 70% at 6 h. PJ34 also prevented the increase in mRNAs encoding IL-6 (-41%), E-selectin (-81%) and ICAM-1 (-54%). PJ34 (25 mg kg(-1)) reduced the infarct volume (-26%) and improved neurological deficit, 24 h after ischemia. CONCLUSIONS AND IMPLICATIONS: PJ34 inhibited the increase in the mRNAs of four inflammatory mediators, caused by cerebral ischemia. The contribution of this effect of PJ34 to neuroprotection remains to be clarified.

A comparative study on intra-articular versus systemic gene electrotransfer in experimental arthritis.

BACKGROUND: Electric pulse mediated gene transfer has been applied successfully in vivo for increasing naked DNA administration in various tissues. To achieve non-viral gene transfer into arthritic joint tissue, we investigated the use of electrotransfer (ET). Because anti-inflammatory cytokine strategies have proven efficient in experimental models of arthritis, we compared the therapeutic efficiency of local versus systemic delivery of the interleukin-10 (IL-10) using in vivo ET. METHODS: A plasmid vector expressing IL-10 was transferred into DBA/1 mouse knee joints by ET with 12 pulses of variable duration and voltage. The kinetics of transgene expression were analyzed by specific enzyme-linked immunosorbent assay (ELISA) in sera and knees. Optimal conditions were then used to deliver increasing amounts of IL-10 plasmid intra-articularly (i.a.) in the collagen-induced arthritis (CIA) mouse model. The therapeutic efficiency was compared with the potency of intra-muscular (i.m.) ET. RESULTS: Following i.a. ET, local IL-10 secretion peaked on day 7 and dropped 2 weeks after. A second ET produced the same kinetics without enhancing gene transfer efficiency, while transgene was still detected in injected muscles 4 weeks after ET. Only the i.m. ET of 25 microg of IL-10 significantly inhibited all the clinical and biological features of arthritis. The i.a. ET only showed mild improvement of arthritis when 100 microg of IL-10 plasmid were electrotransfered weekly from day 18 following arthritis induction. CONCLUSIONS: The present results suggest that gene transfer into arthritic joints by ET is an effective means to deliver anti-inflammatory cytokines. However, short duration of transgene expression impedes a significant effect for the treatment of arthritis, making i.m. ET more potent than i.a. ET for clinical benefit in CIA.