Quantification of neurotrophins in skeletal muscle following nerve injury: Comparison between spinal cord injury and peripheral nerve injury

Purpose: We investigated the kinematics of nerve growth factor (NGF)mRNA and brain-derived neurotrophic factor (BDNF)mRNA in a skeletal muscle following spinal cord and peripheral nerve injuries by utilizing the reverse-transcription polymerase chain reaction/high-performance liquid chromatography (RT-PCR/HPLC) method. Methods: We made mice models of spinal cord transection and sciatic nerve transection, plus sham and control groups. After RNA extraction from gastrocnemius muscle of mice, RT-PCR was done. We measured the levels of NGFmRNA and BDNFmRNA in a skeletal muscle following spinal cord and peripheral nerve injuries by utilizing the RT-PCR/HPLC method. All values are analyzed and graphed as means ±SED. Bonferroni test (Post-hoc test) was used when two values were compared. Differences were considered statistically significant when p < 0.05. Results: According to the wet muscle weight, at day 7, a significant difference was found between the peripheral lesion and control group, and at days 14 and 28, significant differences were found between the spinal and peripheral lesion and control group. According to the NGFmRNA, in the peripheral nerve injury group, the levels increased up to day 28 and when compared with the control group, the levels were significantly higher at days 14 and 28. According to the BDNFmRNA, levels at days 2, 7, 14, and 28 were significantly lower in the spinal cord injury group than in the control group. However, in peripheral nerve injury group, when compared with the control group, the levels significantly increased at days 7, 14, and 28. Conclusion: We clarified marked differences in chronological changes in neurotrophin kinetics in a skeletal muscle between spinal cord injury and peripheral nerve injury.