The influence of ageing of extracellular matrix gives differentiation of osteoblasti.

众所周知，骨形成随着年龄的增长而稳步下降，导致骨量的显著损失。一般认为，衰老过程中骨的丢失是由于骨形成的重要性和骨吸收的增加。目前流行的一种假说认为，在正常细胞代谢过程中产生的氧自由基或活性氧物质（有几种类型）是衰老过程的主要因素。活性氧通常对活细胞有毒，因为它们修饰和破坏各种生物学上重要的分子。众所周知，自由基如超氧阴离子和一氧化氮已被证明在骨细胞骨吸收中起作用。我们以前报道过，大鼠颅骨成骨细胞在羟基自由基处理的纤维连接蛋白基质上培养时，骨结节形成减少。此外，碱性磷酸酶活性和分泌的1型胶原蛋白，以及这些mRNA水平的羟基自由基处理的FN基质降低。本研究旨在建立H_2O_2对成骨细胞功能影响的细胞培养体系，探讨H_2O_2对成骨细胞功能的影响。结合以往的研究和本研究，可以认为氧化应激在骨吸收和骨形成中起重要作用。因此，实验模型，如这里提出的也可能是有用的调查成骨细胞功能的老化。结论：衰老过程中产生的氧化应激影响骨相关基因的表达和细胞分化，导致成骨细胞矿化能力降低。

It is well known that bone formation steadily declines with age resulting in significant loss of bone mass. It is generally believed that the loss of bone in senescence is due to an important of bone formation and an increase of bone resorption. A currently popular hypothesis postulates that the oxygen free radical or reactive oxygen species, of which there are several types, produced during normal cellular metabolism, is a major contributor to the ageing process. Active oxygen species are generally toxic to living cells because they modify and damage various biologically important molecules. It is also well known that free radical such as superoxide anion and nitric oxide have been shown to play a role of osteoclastic bone resorption. We previously reported that bone nodule formation by rat calvarial osteoblasts was reduced when the cells were cultured on hydroxy radical treated fibronectin substratum in vitro. Further, alkaline phosphatase activity and secretion of type 1 collagen as well as those mRNA levels were decreased by hydroxy radical treated FN substratum. These findings suggested that the hydroxy radical damaged FN molecules and reduced the bone formation of osteoblast cells via inhibition of proliferation and/or differentiation of osteoblast progenitors and the calcification process.The purpose of this study is to establish the cell culture system to investigate the effect of H_2O_2 on osteoblast function involved in bone mineralization rate using MC3T3-E1 cells. Taken together with previous study and our present study, it is conceivable that oxidative stress is important role of bone resorption and bone formation. Therefore, experimental models such as presented here may also be useful investigating osteoblast function an ageing. In conclusion, the oxidative stress produced during ageing affect bone-related gene expression and cell differentiation, and it cause the reduction of mineralization of osteoblasts.