光生物调节对中度创伤性脑损伤小鼠损伤修复的影响

Effects of photobiomodulation on damage repair after moderate traumatic brain injure

  • 摘要: 背景 创伤性脑损伤(traumatic brain injury,TBI)作为高致残致死率的神经系统疾病,其治疗手段亟待创新。光 生物调节(photobiomodulation,PBM)作为一种新的非侵入性物理疗法,但目前针对中度TBI的作用机制及疗效参数仍缺乏 系统性研究。目的 探究PBM对中度TBI小鼠损伤修复的影响及其可能机制。方法 36只8周龄的雄性C57BL/6小鼠随机 采用随机数表法分为假手术组(Sham组)、TBI组和PBM组。TBI组和PBM组采用控制皮质冲击损伤法构建中度TBI模型; Sham组仅行相同伤口处理而不进行脑皮层冲击损伤;PBM组接受1064nm光治疗,功率密度为25 mW/cm²,每天12 min, 为期14 d。行为学上通过疲劳转棒、Y迷宫等行为学试验评估小鼠运动和认知功能。组织学上通过免疫荧光染色观察脑组 织冰冻切片胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、微管相关蛋白2(microtubule-associated protein 2, MAP2)表达变化,分子生物学上采用实时荧光定量聚合酶链式反应(quantitative real-time polymerase chain reaction,qRT PCR)检测损伤区周围脑组织中脑源性神经营养因子(brain-derived neurotrophic factor,BDNF),星形胶质细胞肿瘤坏死因子 α(tumor necrosis factor α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)、白细胞介素6(interleukin 6,IL-6)的表达变化。 结果 在行为学方面,疲劳转棒实验显示PBM组小鼠相对于TBI组小鼠平均跌落时间延长,运动的距离明显增加,掉落时 速度更快(P<0.05)。Y迷宫实验显示PBM组小鼠相对于TBI组小鼠进入新异臂探索的时间和次数均增加(P<0.05)。在组 织层面,TBI组损伤区脑组织MAP2的平均荧光强度显著低于Sham组和PBM组,GFAP的平均荧光强度显著高于Sham组 和PBM组,差异均具有统计学意义(P<0.05),qRT-PCR结果显示与TBI组相比,PBM组小鼠损伤区的BDNF相对mRNA 水平表达显著升高(P<0.05)。在细胞层面,PBM治疗后炎性活化的星形胶质细胞中TNF-α、IL-1β、IL-6的表达显著下降 (P<0.05)。结论 1 064 nmPBM可能通过促进神经元损伤修复,抑制星形胶质细胞活化,以及降低其促炎因子水平来改善 TBI后的运动及认知功能。

     

    Abstract: Background Traumatic brain injury (TBI), as a neurological disorder characterized by high disability and mortality rates, demands urgent innovation in therapeutic approaches. Although photobiomodulation (PBM) demonstrates potential as a novel non-invasive physical therapy, current research lacks systematic investigation into its mechanisms of action and efficacy parameters specifically for moderate traumatic brain injury. Objective To investigate the neuroprotective effects and potential mechanisms of 1064 nm PBM in moderate TBI models.Methods Thirty six 8-week-old male C57BL/6 mice were randomized into Sham group, TBI group, and PBM group. The TBI group and the PBM group were established using controlled cortical impact injury to model moderate brain injury, while the sham surgery group underwent identical craniotomy procedures without cortical impact induction. The PBM group received daily 1064 nm irradiation (25 mW/cm², 12 min/day) for 14 consecutive days. Behavioral assessments employing rotarod fatigue testing and Y-maze paradigms were implemented to quantify locomotor coordination and spatial working memory, while histopathological evaluation utilizing immunofluorescence staining on cryopreserved cerebral sections enabled quantitative analysis of glial fibrillary acidic protein (GFAP) astrogliosis and microtubule-associated protein 2 (MAP2) neuronal integrity, complemented by molecular profiling through quantitative real-time PCR (qRT-PCR) that systematically measured transcriptional alterations in brain-derived neurotrophic factor (BDNF) and astrocyte-mediated pro-inflammatory cytokines including tumor necrosis factor- α (TNF- α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) within peri-contusional parenchyma.Results Rotarod test showed that the mean fall time was shortened following TBI and prolonged after PBM treatment. The mice in PBM group have a significantly longer distance of movement and a faster speed when falling relative to TBI mice (P < 0.05). The Y maze experiment showed that mice in the PBM group have an increase in the time and number of times to explore the new isometric arm relative to the TBI mice (P < 0.05). The expression of relative mRNA levels of BDNF in the brain tissues of the injury area in TBI mice was significantly lower than that in the Sham and PBM groups (P < 0.05). The mean fluorescence intensity of MAP2 in the brain tissue of the injury area in the TBI group was also significantly lower than that in the Sham and PBM groups, and the mean fluorescence intensity of GFAP was significantly higher than that in the Sham and PBM groups, with the differences being statistically significant (P < 0.05). In the vitro experiment, the expression of TNF- α, IL-1β and IL-6 in astrocytes was significantly decreased after PBM treatment, and the difference was statistically significant (P < 0.05).Conclusion 1064 nm PBM may improve motor and cognitive functions after moderate TBI by promoting the repair of neuronal damage, inhibiting the activation of astrocytes, as well as decreasing their levels of pro-inflammatory factors.

     

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