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目的探讨颅脑创伤(TBI)大鼠外周血液白细胞端粒长度的变化趋势及与神经功能损伤症状严重程度的相关性。方法将40只SD大鼠随机等分为轻度TBI组、中度TBI组、重度TBI组和空白组,每组10只。除空白组外,其余组利用皮质撞击致伤法构建不同损伤程度TBI大鼠模型。于术后72 h进行神经功能损伤评分(m NSS),并分别于术前和行为学评分完成后行眶下静脉丛取血,提取基因组DNA,real-time PCR法测量端粒长度。结果TBI各组的m NSS评分均明显高于空白组(P均<0.05),且轻度、中度、重度TBI组mNSS评分依次增高,差异均有统计学意义(P均<0.05)。术前各组大鼠端粒长度比较差异均无统计学意义(P均>0.05);术后72 h,中度和重度TBI组端粒长度均明显短于自身术前及空白组(P均<0.05),且重度TBI组端粒长度明显短于轻度和中度TBI组(P均<0.05);中度和重度TBI组端粒长度与mNSS评分呈负相关(r=-0.505,P<0.05)。结论大鼠中重度TBI后72 h端粒显著缩短,且TBI损伤越严重,端粒缩短越显著;端粒长度与神经功能损伤严重程度呈负相关,端粒越短,神经功能损伤症状越严重。
Objective To investigate the change trend of telomere length of peripheral blood leukocytes in the brain of traumatic brain injury (TBI) rats and its correlation with the severity of neurological injury. Methods 40 SD rats were randomly divided into mild TBI group, moderate TBI group, severe TBI group and blank group, with 10 rats in each group. Except the blank group, the other groups used cortical impact injury method to construct TBI rat models with different degree of injury. Neurological impairment score (m NSS) was measured at 72 h after operation. Blood samples were obtained from the infraorbital foramen before and after the behavioral score was completed. The genomic DNA was extracted and the telomere length was measured by real-time PCR. Results The m NSS score of each TBI group was significantly higher than that of the blank group (all P <0.05), and the mNSS scores of mild, moderate and severe TBI groups were significantly higher than those of the blank group (all P <0.05). There was no significant difference in the telomere length between the pre-operation groups (P> 0.05). The telomere length of the moderate and severe TBI groups at 72 h after operation were significantly shorter than those in the preoperative and postoperative groups <0.05). The telomere length in severe TBI group was significantly shorter than that in mild and moderate TBI group (all P <0.05). The telomere length in moderate and severe TBI group was negatively correlated with mNSS score (r = -0.505, P <0.05). Conclusion The telomere shortened significantly at 72 h after TBI, the damage of TBI was more serious and telomere shortening was more significant. The length of telomere was negatively correlated with the severity of neurological injury. The shorter the telomere, the more severe the neurological injury .