Oxidative stress and Neurodegenerative diseases: The effect of quercetin on morphological features of apoptosis

Background and Aim : During spinal cord injuries and neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS), apoptosis of motor neurons is reported. In order to extensive researches still there is no universally accepted treatment for these diseases. Therefore, studying on mechanisms involved in apoptosis of motor neurons can be helpful for survival of these neurons. Since, oxidative stress is one of the reasons for apoptosis of motor neurons the application of antioxidants might be effective on viability of these neurons. There for, the aim of this study was to investigate if, quercetin as a powerful antioxidant with reducing oxidative stress, delay the apoptosis of the motor neurons in cultured spinal cord slices.Methods : Thoracic region of spinal cord of NMRI adult mouse was cut in to 500 μm slices using a tissue chopper. The slices were then divided to three groups: 1. Freshly prepared slices (0 hour); 2. Control slices; 3. Slices treated by quercetin with effective concentration (100 μM). The control and the treated slices were cultured in a medium for 6 hours in a CO2 incubator. After fixation, the slices were cut using a cryostat. Morphological features of apoptosis in the motor neurons was studied using fluorescent staining including Hoechst and propidium iodide. MTT [3-(4,5-dimethylthiazol-2-y1)2,5-diphenyltetrazolium bromide] assay was used to evaluate slice viability in three groups. Data were analyzed using one-way ANOVA and Tukey’s test.Results : After 6 hours -compared to the control group- the motor neurons displayed morphological features of apoptosis including cell shrinkage as well as nuclear and chromatin condensation. In addition, the viability of cultured slices, significantly decreased as compared to freshly prepared slices. At this time point, quercetin not only delayed morphological features of apoptosis in the motor neurons compared to the control group but also significantly compensate the cell viability in the cultured slices.Conclusion : Since, quercetin, as a potent antioxidant, was able to delay the morphological features of apoptosis and increase the viability of motor neurons of cultured spinal cord slices, it is possible that oxidative stress is responsible for apoptosis of the motor neurons.

Keywords:

Apoptosis , Oxidative stress , Quercetin , Motor neuron , Spinal cord slices