Evaluation of Regenerative Effects of Neurotrophin-3 and Neurotrophin-4/5 on Peripheral Sensory Neurons Injured with Laser Microdissection Technique

Objective: To investigate whether of NT3 and NT4/5, important members of the neurotrophin family, affect the survival ability of dorsal root ganglion (DRG) neurons that were created axon injury (axotomy) with a microscope-controlled laser microdissection technique. Materials and Methods:6-12 week BALB/c mice were used in the study. DRGs were harvested from mice under aseptic conditions and deep anesthesia. Primer DRG neuron culture was prepared. Forty-eight hours after cell culture, the cultures were treated with NT3 (50 ng / ml), NT4 / 5 (50 ng / ml) and NT3-NT4/5 combination. Neurites were axotomized at 200 μm distance from the perikaryon with the microscope-controlled laser beam. A propidium iodide (PI) uptake test was performed to determine the dead-alive distinction of neurons. Neurons were visualized with a time-lapse fluorescent microscopic imaging system. Results: PI show the dead cells' nucleus as bright red under the fluorescence microscope. All experimental groups showed a significant increase in axotomized-neurons’ survival rates at 24th and 48th hours according to the control group. It was determined that the highest survival rate was in NT3 + NT4 group, then NT3, NT4 and control groups respectively. Although the survival rates decreased compared to the 24th hour at the 48th hour, this decrease was statistically insignificant. Conclusion: Combination of NT3-NT4/5, NT3 (50 ng/ml) and NT4/5 (50 ng/ml) increase the survival rate of DRG neurons in vitro axotomy injury model. These neurotrophic factors have therapeutic potential in the mechanical injury of peripheral nerves