Interrelationship between silicon, aluminum, and elements associated with tissue metabolism and degenerative processes in degenerated human intervertebral disc tissue

There is a growing body of evidence concerning the significant role of silicon in development and composition of both connective and bone tissue. Bio-essential silicon shows strong chemical and biological affinity to aluminum, which is toxic and biologically inessential element. The presence of silicon was confirmed in a variety of tissues; however, it has never been examined in intervertebral disc tissue, neither in healthy nor in degenerated one. In this paper, for the first time in the literature, we present the content of silicon in the degenerated intervertebral disc tissue. We also compared the results of silicon analysis with aluminum values in degenerated intervertebral disc tissue in humans. We used chemometric methods to find correlations and similarities between silicon, aluminum, and elements associated with tissue metabolism (Mg) and degenerative processes (Zn and Cu). The presence of silicon was confirmed in all 30 samples harvested from 22 patients operated on due to degenerative changes. Its concentration was within the range of 5.37-12.8 μg g-1 d.w., with the mean concentration of 7.82 μg g-1 d.w. The analysis showed significant correlation between Si and both Al and Mg and weak or negative correlation with Zn and Cu, where the latter was probably the result of degenerative processes. Although silicon is considered essential in glycosaminoglycan and collagen synthesis in connective tissue, it did not show any correlation nor similarities with elements reflecting changes associated with the degenerative process of the intervertebral disc. Silicon showed significant correlation with aluminum, similar to those observed in other human tissues.