Effects of Nitric Oxide Production Inhibitor Named, NG-Nitro-L-Arginine Methyl Ester (L-NAME), on Rat Mesenchymal Stem Cells Differentiation

Introduction & Recently, the findings of some studies have shown that, nitric oxide (NO) probably has an important role in differentiation of mesenchymal stem cells to osteoblasts. The aim of the present investigation was to study the effects of nitric oxide production inhibitor named, NG-nitro-L-arginine methyl ester (L-NAME), on rat mesenchymal stem cells differentiation to osteoblasts in vitro. This was an experimental study conducted at Hamedan University of Medical Sciences in 2009, in which rat bone marrow stem cells were isolated in an aseptic condition and cultured in vitro. After third passage, the cells were cultured in osteogenic differentiation medium. To study the effects of L-NAME on osteogenic differentiation, the L-NAME was added to the culture medium at a concentration of 125, 250, and 500 μM in some culture plates. During the culture procedure, the media were replaced with fresh ones, with a three days interval. After 28 days of culturing; the mineralized matrix was stained using Alizarian red staining method. The gathered data were analyzed by SPSS software version 12 using one way ANOVA. The findings of this study showed that in the presence of L-NAME, differentiation of bone marrow mesenchymal stem cells to osteoblasts was disordered and matrix mineralization significantly decreased in a dose dependent manner. This study revealed that, inhibition of nitric oxide production using L-NAME can prevent the differentiation of rat bone marrow mesenchymal stem cells to osteoblast. The results imply that NO is an important constituent in differentiation of mesenchymal stem cell to osteoblasts.