Protective effect of curcumin and Curcuma longa extract on apoptosis of motor neurons in cultured spinal cord slices of adult mouse

Introduction: Since Curcuma longa extract and curcumin have been shown to be potent antioxidant agents, they were used in cultured adult mouse spinal cord slices to investigate whether they can inhibit apoptosis in motor neurons. Methods: Slices from the thoracic region of adult mice spinal cord were divided into four groups: 1. Freshlyprepared slices (time 0); 2. Control; 3. Slices treated by curcumin (20 μM); and 4. Slices treated by Curcuma longa extract (1000 ppm). The control and the treated slices were cultured for 6 hours. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide] assay was used to evaluate slice viability in the four groups. Morphological and biochemical features of apoptosis were studied using fluorescent staining (propidium iodide and Hoechst 33342) and TUNEL method, respectively. Data were analyzed using one-way ANOVA. Results: The viability of slices cultured for 6 hours (control) was considerably decreased compared to freshlyprepared slices. Motor neurons from slices cultured for 6 hours showed morphological and biochemical features of apoptosis. At this time point, the application of either curcumin or Curcuma longa extract not only increased the viability of cultured slices compared to the control, but also they could inhibit morphological and biochemical features of apoptosis in the motor neurons. Conclusion: Oxidative stress might be a possible mechanism for the induction of apoptosis of motor neurons in cultured spinal cord slices.