苯肾上腺素对大鼠成骨细胞放射损伤的保护作用

Protective effect of phenylephrine on irradiated injury of osteoblasts in rats

目的:探讨苯肾上腺素对放射损伤大鼠成骨细胞的细胞形态以及烟酰胺磷酸核糖转移酶(Nampt)mRNA表达水平的影响,阐明苯肾上腺素对其可能的保护作用机制。方法:组织块法培养大鼠颅骨成骨细胞,随机分为空白对照组、苯肾上腺素组、单纯照射组和苯肾上腺素+照射组。苯肾上腺素组在照射前0.5h以100mmol·L-1苯肾上腺素孵育成骨细胞,照射组给予成骨细胞8Gy X射线照射。照射后8、16、32和64h在倒置显微镜下观察并分别收集细胞,提取细胞总RNA,应用RT-PCR法检测成骨细胞Nampt mRNA表达水平。结果:倒置显微镜下,与空白对照组比较,苯肾上腺素组成骨细胞形态、数量未见明显改变;单纯照射组细胞形态发生明显皱缩,尤以8h明显,细胞数量在8、16、32和64h时分别是对照组的0.82、0.37、0.24和0.21倍;苯肾上腺素+照射组在照射8和16h后细胞皱缩,32h后其形态恢复,在8、16、32和64h后其数量分别为空白对照组的0.91、0.83、0.72和0.75倍,是单纯照射组的1.09、2.24、3.00和3.60倍。RT-PCR法检测,在照射8、16、32和64h后,单纯照射组、苯肾上腺素+照射组Nampt mRNA表达水平较空白组明显减少(P<0.01),苯肾上腺素+照射组较单纯照射组明显增加(P<0.01)。结论:苯肾上腺素可减轻电离辐射导致的大鼠成骨细胞萎缩,并上调Nampt mRNA表达水平,其对成骨细胞放射损伤的保护作用可能与上调Nampt mRNA表达水平有关。

Objective To investigate the effect of phenylephrine on the morphology and the expression level of Nampt mRNA in the irradiated osteoblasts of the rats,and to clarify the possible protective effects of phenylephrine on this injury.Methods The osteoblasts cultured by conventional tissue were randomly divided into control group, phenylephrine group,simple irradiation group,and phenylephrine＋irradiation group.The cells in phenylephrine group were treated with 100 mmol· L-1 phenylephrine 30 min before irradiation.The cells in simple irradiation group were irradiated with 8 Gy X-ray.The osteoblasts were observed by microscope and were collected at the time points of 8,16,32 and 64 h after irradiation.The Nampt mRNA expression level in osteoblasts was examined by RT-PCR.Results There was no obviously morphological and number changes of osteoblasts in phenylephrine group compared with control group.The osteoblasts in simple irradiation group were atrophied,especially at 8 h;the number of osteoblasts in simple irradiation group was 0.82,0.37,0.24 and 0.21 times as control group respectively at 8,16,32 and 64 h. Atrophy of osteoblasts was alleviated in phenylephrine＋irradiation group;at 8, 16,32 and 64 h,the number of osteoblasts was 0.91,0.83,0.72 and 0.75 times as control group,and was 1.09,2.24,3.00 and 3.60 times as simple irradiation group. The expression level of Nampt mRNA in the osteoblasts in simple irradiation group was reduced compared with control group （P 〈 0.01） at 8, 16, 32 and 64 h.There were significant differernces of the expression levels of Nampt mRNA in the osteoblasts between phenylephrine＋irradiation group and control group （P 〈 0.01）,and there were significant differernces between phenylephrine ＋ irradiation group and simple irradiation group （P 〈 0.01 ） at the different time points. Conclusion Phenylephrine could reduce the atrophy of osteoblasts in the rats induced by irradiation and up-regulate the expression level of Nampt mRNA.Its protective effect on irradiated injury may be related to the up-regulation of the expression level of Nampt mRNA.