他莫昔芬对急性脊髓损伤模型大鼠的神经保护

Neuroprotective effect of tamoxifen in a model rat with aucte spinal cord injury

背景:研究表明,他莫昔芬能通过减轻脑出血及脊髓损伤部位周围水肿情况,从而发挥神经保护作用。目的:分析他莫昔芬在大鼠脊髓损伤中的神经保护作用及相关机制。方法:SD大鼠60只分为5组,每组12只。除假手术组外,均采用Allen法(70 g·cm)建立SD大鼠T10脊髓损伤模型。他莫昔芬2.5,5.0,10 mg/kg组,造模后30 min开始分别给予2.5,5.0,10 mg/kg他莫昔芬腹腔注射,注射1次/d,假手术组和脊髓损伤组每日注射等量生理盐水。术后24,48,72 h进行神经功能评分(BBB评分),72 h取出损伤脊髓检测损伤脊髓水肿情况;利用ELISA法检测72 h后炎性因子肿瘤坏死因子α、白细胞介素1β、白细胞介素6活性,以及凋亡蛋白Caspase-3活性;Western-blot法检测核因子κB p65、磷酸化核因子κB抑制因子α以及凋亡蛋白Caspase-3的表达量。结果与结论:1与脊髓损伤组相比,他莫昔芬组大鼠后肢能够明显改善;272 h后他莫昔芬可显著降低脊髓损伤的水含量,抑制脊髓水肿;3ELISA结果显示他莫昔芬能显著降低脊髓损伤中炎性因子肿瘤坏死因子α、白细胞介素1β、白细胞介素6活性(P<0.05);4Western-blot结果显示他莫昔芬能显著抑制核因子κB p65、磷酸化核因子κB抑制因子α蛋白以及凋亡蛋白Caspase-3的表达。5结果表明:他莫昔芬可通过减轻脊髓损伤的炎性反应和抑制细胞凋亡从而发挥神经保护作用。

BACKGROUND：Tamoxifen has been found to exert neuroprotection by reducing cerebral hemorrhage and edema surrounding the injured site of the spinal cord. OBJECTIVE：To investigate the neuroprotective effect of tamoxifen on rat acute spinal cord injury and the underlying mechanism. METHODS：Sixty Sprague-Dawley rats were equivalently randomized into five groups, and modeled into spinal cord injury at T10 level using modified Al en’s weight-drop method （70 g/cm）, except those in sham operation group. At 30 minutes after modeling, al rats were given the intraperitoneal injection of 2.5, 5.0 and 10 mg/kg tamoxifen or same amount of normal saline, once daily. Basso, Beattie, Bresnahan （BBB） scores were recorded at 24, 48 and 72 hours after surgery. The injured spinal cord was removed at 72 hours to observe its edema. Meanwhile, the levels of interleukin-1β, interleukin-10 and tumor necrosis factor-α, as wel as Caspase-3 activity were detected by ELISA;the protein levels of nuclear factor-κB p65, phosphorylated I-κBαand Caspase-3 were detected by western blot assay. RESULTS AND CONCLUSION：Compared with the model group, the hind limb function in the tamoxifen groups was significantly improved. Tamoxifen significantly decreased the water content in the rat spinal cord and inhibited spinal cord edema at 72 hours after surgery. ELISA results showed that tamoxifen significantly reduced the activity of interleukin-1β, interleukin-10, tumor necrosis factor-αand Caspase-3 （P〈0.05）. Western blot assay revealed that tamoxifen significantly downregulated the expression levels of nuclear factor-κB p65, phosphorylated I-κBαand Caspase-3. These results suggest that tamoxifen protects against spinal cord injury via suppressing inflammatory response and apoptosis-associated proteins.