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目的:观察体外培养的新生SD大鼠颅顶骨骨缝在牵张力作用下,一氧化氮合酶(Nitric Oxide Synthase,NOS)三种同形异构体(eNOS,nNOS,iNOS)的表达及分布;探讨一氧化氮(nitric oxide,NO)在机械应力调节骨缝组织改建过程中所起的作用。方法:取一周龄SD大鼠颅顶骨正中矢状缝组织块进行体外器官加力培养。实验组施加0.2g张力,对照组将弹簧固定不施力,两组分别于0、1、6、24、48h收获标本。标本用常规免疫组化的方法,分别检测NOS三种同形异构体在颅骨缝组织中的分布和表达变化情况。结果:正常新生SD大鼠颅骨缝组织中内皮型一氧化氮合酶(eNOS)及神经元型一氧化氮合酶(nNOS)有轻微表达,而诱导型一氧化氮合酶(iNOS)基本不表达;施加机械张力后,三种NOS在颅骨缝组织中的表达强度及位置随受力时间长短均有改变。eNOS在最初就有少量表达,6h表达开始增加,24h呈强阳性高表达,48h各种细胞表达强度均有所减弱。nNOS在不同时间点均有较弱表达,其结果无统计学意义(P>0.05)。iNOS在对照组和加力0h基本未见表达;加力1h后偶有成骨细胞、成纤维细胞弱表达;加力6h组可见散在轻微表达;加力24h组各种骨缝细胞均显著表达;加力48h,骨缝组织各种细胞表达呈强阳性。结论:机械牵张力刺激可以导致内源性eNOS及iNOS生成的增加,NO可能在机械张力调节骨缝组织改建过程中发挥重要作用。
OBJECTIVE: To observe the expression and distribution of three isoforms of nitric oxide synthase (NOS) under the tension-inducing effect in cultured neonatal SD rats. To investigate the role of nitric oxide (NO) in the process of mechanical stress-induced osteosynthesis. Methods: One-week-old SD rat calvaria medial sagittal suture tissue was used for organ culture in vitro. In the experimental group, 0.2g tension was applied, while in the control group, the spring was fixed and no force was applied. The two groups were harvested at 0, 1, 6, 24 and 48 hours respectively. Specimens with conventional immunohistochemical methods were detected three kinds of NOS isoforms in the cranial suture distribution and expression changes. Results: The expressions of eNOS and nNOS in the skull seams of normal newborn rats were slightly expressed, whereas the inducible nitric oxide synthase (iNOS) After the application of mechanical tension, the expression intensity and location of three kinds of NOS in the calvarial tissue changed with the duration of stress. eNOS initially showed a small amount of expression, increased at 6 hours, strongly positive at 24 hours, and weakened at 48 hours. nNOS had weaker expression at different time points, the result was not statistically significant (P> 0.05). iNOS in the control group and after 0h basic no expression; after 1h force occasionally osteoblasts, fibroblasts weakly expressed; force 6h group visible scattered slightly expressed; force 24h groups were significantly different suture cells At 48h, the expression of various cells in the suture was strongly positive. CONCLUSIONS: Mechanical stretch-induced stimulation can lead to the increase of endogenous eNOS and iNOS production. NO may play an important role in the process of mechanical tension-induced osteosynthesis.