| Summary: | 碩士 === 中原大學 === 醫學工程研究所 === 91 === <a href="http://www.ntsearch.com/search.php?q=Smoking&v=56">Smoking</a> has been implicated as a risk factor in post- menopausal osteoporosis. The major component of the particulate phase of all cigarette smoke is nicotine. It could affect the regulation of bone mass. The balance between bone formation and resorption is determined by numbers and activity of osteoblast and osteoclast. Most prevalent metabolic bone diseases, such as osteoporosis, are due to an imbalance in bone remodeling. <a href="http://www.ntsearch.com/search.php?q=Single&v=56">Single</a> pulsed electromagnetic field (sPEMF) stimulations were confirmed to modulate the bone formation and resorption, which are carried out by osteoblasts and osteoclasts respectively.
This study demonstrated the effect of specific <a href="http://www.ntsearch.com/search.php?q=single&v=56">single</a> pulsed electromagnetic field inhibiting osteoblast apoptosis induced by nicotine. Osteoblastic MC3T3-E1 cells were treated with nicotine (1μM to 16mM). At the same <a href="http://www.ntsearch.com/search.php?q=time&v=56">time</a>, MC3T3-E1 cells were exposed by sPEMF (7.5Hz) at 1.3 Gauss for 8hr. There are two approachs used in this study to examine the apoptosis. The first approach is colorimetric tetrazolium (MTT) assay which is a method for determining the number of cell viability. MTT was converted into a purple formazan reaction product by redox of living cells. The formazan was then dissolved by DMSO and read on a microplate reader at a wavelength of 570nm. The second one is Western blot analysis method, which is an approach of analyzing proteins by probing immunoblots with antibodies against poly ADP-ribose polymerase (PARP) and Bcl-2.
Increasing of nicotine dose decreases the survival rate of MC3T3-E1 cells. In addition, the dose increase enhances the expression of PARP cleavage. It is known that the expression of PARP cleavage indicates the presence of damaged DNA. As a result cell apoptosis takes place. By knowing so, it is reasonable to assume PARP cleavage plays an important role in early apoptosis. These results suggest that nicotine be associated with the expression of cell death genes. In other words, nicotine can cause bone cells apoptosis.
We compared the survival rate of MC3T3-E1 cells between with and without sPEMF stimulations. The results of this study show the number of cells survived stimulated by sPEMF is significantly higher than those with sPEMF stimulation. This result is also verified by the Western blot assay method. In the Western blot analysis, we found the expression of Bcl-2 is enhanced. This finding indicates MC3T3-E1 cells are well protected and cell apoptosis is reduced.
Based upon the above study result, we conclude that nicotine can cause MC3T3-E1 cell apoptosis. Yet, higher dose nicotine aggravates cell apoptosis. Furthermore, sPEMF can reduce apoptosis of osteoblasts and increase the survival rate of osteoblasts by enchanced the expression of Bcl-2. This suggestes that sPEMF of 1.3 Gauss could reduce apoptosis of MC3T3-E1 cells and increase MC3T3-E1 cells viability.
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