نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری رشته فیزیولوژی ورزشی، گروه تربیت بدنی و علوم ورزشی، واحد بجنورد، دانشگاه آزاد اسلامی، بجنورد، ایران.
2 استادیار گروه تربیت بدنی و علوم ورزشی، واحد بجنورد، دانشگاه آزاد اسلامی، بجنورد، ایران.
3 استادیار گروه فیزیک پزشکی و رادیولوژی، دانشگاه علوم پزشکی خراسان شمالی، بجنورد، ایران.
4 استادیار گروه بیوتکنولوژی پزشکی، دانشگاه علوم پزشکی خراسان شمالی، بجنورد، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Extended Abstract
Background and Aim: Spinal cord injuries result in the loss of sensation and voluntary movement in the lower limbs (1). Tropomyosin receptor kinase B (TrkB), a neurotrophin receptor, was named after the oncogene that led to its discovery (2). Phosphatidylinositol-3-kinases (PI3Ks) are a group of multifunctional enzymes involved in various metabolic processes that regulate cellular physiology (3).
Aerobic exercise has been proposed as a promising noninvasive strategy for maintaining motor and respiratory muscle flexibility following spinal cord injury (4). This study aimed to examine the effects of four weeks of aerobic training, with one or two sessions per day, on motor performance and hippocampal TrkB and PI3K gene expression in rats with spinal cord injury.
Materials and Methods: Forty-two male rats (age: 10–12 weeks, weight: 225–275 g) were randomly divided into six equal groups as: healthy control group, healthy control group + first training protocol, healthy control group + second training protocol, spinal cord injury group, spinal cord injury group + first training protocol, and spinal cord injury group + second training protocol. Seven rats were included in each group (5). All groups, except the healthy control group, underwent general anesthesia and spinal cord injury (SCI). Anesthesia was induced via intraperitoneal injection of ketamine (75 mg/kg body weight) and xylazine (10 mg/kg body weight).
After marking the incision site, a 2.5 cm longitudinal incision was made along the spine. The superficial and deep fascia were dissected, and the muscles adjacent to the T9–T11 vertebrae were retracted. Laminectomy was performed at the T11 vertebra using a dental burr attached to a small drill. The spinal cord was then injured by delivering a 25 mm drop of a 10-gram weight via a hollow cylinder while the vertebrae were stabilized using a stereotaxic device. The muscles and fascia were immediately sutured using absorbable suture (No. 4-0). The healthy groups underwent laminectomy only without spinal cord injury (6).
After two weeks of recovery, all rats performed two types of aerobic exercise with one and two training sessions per day for four weeks. After the training period, motor and molecular tests were performed to measure changes in hippocampal TrkB and PI3K receptor gene expression. One-way analysis of variance was used to compare changes between groups at a significance level of p<0.05.
Results: The results of TrkB receptor gene expression among the groups show that a significant increase in gene expression was observed in the healthy control + one training session per day group compared to the healthy control group and in the healthy control + two training sessions per day group compared to the control group. However, the increase in gene expression in one training session per day compared to the two training sessions per day group was not significantly different. TrkB gene expression in the spinal cord injury model was significantly reduced compared to the control group. This decrease in expression was observed in both spinal cord injury + one and two training sessions per day groups compared to the control group. In addition, TrkB gene expression showed a significant increase in the spinal cord injury + one and two training sessions per day groups compared to the spinal cord injury group. On the other hand, significant changes in gene expression were observed between the spinal cord injury + one training session per day group and the spinal cord injury + two training sessions per day group. PI3K receptor gene expression in the healthy control group was significantly increased compared to the spinal cord injury groups. This was while the changes in the healthy control group showed a significant decrease compared to the healthy control + one and two training sessions per day groups. A significant decrease was observed between the spinal cord injury group and the spinal cord injury + one training session per day group and spinal cord injury + two training sessions per day group. There was no significant difference in gene expression between the spinal cord injury + one training session per day group and spinal cord injury + two training sessions per day group. Similarly, no difference was observed between the healthy control group + one training session per day group and the healthy control + two training sessions per day group.
Conclusion: Exercise protocols, particularly those performed twice daily, not only enhance motor function in animals with spinal cord injury but also positively influence TrkB and PI3K receptor gene expression. These effects may contribute to axonal growth and neuronal survival, playing a crucial role in spinal cord injury recovery.
Keywords: Aerobic exercise, Tropomyosin receptor kinase B, Phosphoinositide 3-kinase, Spinal cord injury.
Ethical Considerations
This study was conducted with the approval of the Ethics Committee of the Vice Chancellor for Research and Technology of North Khorasan University of Medical Sciences with the ethics code IR.NKUMS.REC.1402.058.
Compliance with ethical guideline
Ethical guidelines for working with laboratory animals were strictly followed, including provisions for adequate food, water, and appropriate housing conditions. Ethical considerations were also observed in the humane euthanasia of the mice.
Funding
This research is based on a doctoral thesis from Islamic Azad University, Bojnourd Branch, and was conducted without any financial support.
Conflicts of interest
There are no conflicts of interest regarding this article.
کلیدواژه‌ها [English]
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