mobic and Nerve-Degeneration

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Recent observations link cyclooxygenase type-2 (COX-2) to the progression of the disease. Consistent with this notion, studies with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) show that inhibition and ablation of COX-2 markedly reduce the deleterious effects of this toxin on the nigrostriatal pathway. The similarity between this experimental model and PD strongly supports the possibility that COX-2 expression is also pathogenic in PD.

Topics: Animals; Anti-Inflammatory Agents; Cyclooxygenase 2; Humans; Isoenzymes; Meloxicam; Membrane Proteins; Mice; MPTP Poisoning; Nerve Degeneration; Parkinson Disease; Prostaglandin-Endoperoxide Synthases; Substantia Nigra; Thiazines; Thiazoles

A series of oxicam non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be neuroprotective against 1-methyl-4-phenyl pyridinium in human neuroblastoma SH-SY5Y cells via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway independent of cyclooxygenase (COX) inhibition. The present study endeavored to establish this novel effect of meloxicam (MLX), an oxicam NSAID, in a mouse Parkinson's disease (PD) model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Male C57BL/6 mice, which received MPTP (30 mg/kg/day; s.c.) for 5 consecutive days (chronic model) with 10-day follow-up saline administrations, showed significant motor dysfunction in the pole test due to reduced tyrosine hydroxylase (TH) protein levels in the brain on day 16 after MPTP/saline treatment. Daily coadministrations of MLX (10mg/kg/day; i.p.) and MPTP for the first 5 days and follow-up 10 days with MLX administrations alone (MPTP/MLX treatment) significantly ameliorated MPTP-induced behavioral abnormalities in mice. Concomitant decreases of TH protein levels in the striatum and midbrain of MPTP/MLX-treated mice were not only significantly (p<0.01 and p<0.05, respectively) ameliorated but phosphorylated Akt (pAkt473) expression in the midbrain was also significantly (p<0.01) increased in the midbrain when compared with MPTP/saline-treated mice. These results suggest that MLX, an oxicam NSAID, attenuated dopaminergic neuronal death in the experimental MPTP-PD model by maintenance of the Akt-signaling. Oxicam NSAIDs may serve as potential drugs for PD treatment via a novel mechanism of action.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Anti-Inflammatory Agents, Non-Steroidal; Behavior, Animal; Corpus Striatum; Disease Models, Animal; Dopamine; Hypokinesia; Male; Meloxicam; Mesencephalon; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neuroprotective Agents; Parkinson Disease; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Thiazines; Thiazoles; Tyrosine 3-Monooxygenase

Inflammation is believed to play an important role in the etiology and pathogenesis of Parkinson's disease (PD). However, experimental and epidemiological evidences from various non-steroidal anti-inflammatory drugs, including cyclooxygenase-2 (COX-2) inhibitors, seem contradictive. Using the intranigral lipopolysaccharide (LPS) rat model, we show that meloxicam, a preferential COX-2 inhibitor, diminishes the activation of OX-42-immunoreactive (ir) microglia and reduces the loss of tyrosine hydroxylase (TH)-ir dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) that is normally induced by exposure to LPS. Double-labelling immunohistochemistry identified that activated microglia rather than intact resting microglia are the main intracellular venues for COX-2 expression. These findings suggest that inhibition of COX-2 activity in activated microglial cells may be potentially neuroprotective for DA neurons in the SNpc.

Topics: Animals; CD11b Antigen; Cyclooxygenase Inhibitors; Disease Models, Animal; Dopamine; Lipopolysaccharides; Male; Meloxicam; Nerve Degeneration; Neurons; Rats; Rats, Wistar; Substantia Nigra; Thiazines; Thiazoles; Tyrosine 3-Monooxygenase