Toxic effect of COXª²2 on dopaminergic neurons of substantia nigra in mice with Parkinson¬ðs disease

    SHI Liang, ZHANG Yuª²Xin, ZHANG Zuoª²Feng, CHEN Hao

    Department of Anatomy, North China Coal Medical College, Tangshan 063000, China

    ¡¾Abstract¡¿ AIM: To study the toxic effect of cyclooxygenaseª²2 (COXª²2) on dopaminergic (DA) neurons of the substantia nigra in mice of Parkinson¬ðs disease (PD). METHODS: The PD model was produced according to the Lau¬ðs method. The effects of COXª²2 on the number of COXª²2 immunoreactive cells and DA neurons in the substantia nigra pars compact (SNc), and the expression levels of COXª²2 and tyrosine hydroxylase (TH) in ventral midbrain, including ventral tegmental area (VTA) and substantia nigra (SN), were studied with immunohistochemical analysis and Western blot. The changes of above mentioned indexes, after giving COXª²2 inhibitor to those PD mice, were also studied. RESULTS: Compared with those control mice, the PD mice had the typical behaviors of PD, and the number of DA neurons in SNc and the level of TH in ventral midbrain decreased by about 63% and 77%. Meanwhile, the number of the COXª²2ª²positive cells in SNc and the expression level of COXª²2 in ventral midbrain increased markedly. The PD mice, administered additionally by COXª²2 inhibitor, celecoxib, had slight behavioral symptoms, and the number of DA neurons in SNc and the expression level of TH in ventral midbrain declined by only about 37% and 41%; the number of the COXª²2ª²positive cells in SNc and the expression level of COXª²2 in ventral midbrain were obviously downª²regulated, compared with those simple PD mice. CONCLUSION: COXª²2 is toxic to DA neurons of the PD mice. ......