Effects of strontium ions with potential antibacterial activity on in vivo bone regeneration

Abstract

Background Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration. Methods In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Alizarin Red, Hematoxylin & Eosin (H&E) and Masson’s Trichrome staining were performed to assess bone regeneration and the obtained results were compared with those without Sr. Also, histomorphometric data were obtained to evaluate the new bone, residual graft, and connective tissue. Results Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation showed that although both Gel-BG/Sr and Gel-BG effectively inhibited the growth of Escherichia coli (E. coli) but, only Gel-BG/Sr structure could lead to a 3 log reduction in Staphylococcus aureus (S. aureus). Conclusions: Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.

An osteogenic magnesium alloy with improved corrosion resistance, antibacterial, and mechanical properties for orthopedic applications

“…In our study, the Mg discs displayed higher antibacterial activity than Mg‐Sc discs in S. aureus growth medium owing to their higher corrosion rate and pH values 6,13,38,61‐63 . To combat this reduction in antibacterial properties in Mg‐Sc, we added Sr to improve antibacterial properties of the alloy 64‐67 . Gao et al reported that the in vitro antibacterial tests on Mg‐Sr‐Ga alloy placed it on the top of the ranking list of germ‐killing ability.…”

“…Their results showed the antibacterial properties of pure Mg is improved through the addition of micro‐content of Ga and Sr (0.1 wt%) 68 . Additionally, Baheiraei et al showed Sr incorporation on Gelatin‐bioglass scaffolds effectively enhanced antibacterial activities against both S. aureus and Escherichia coli 64 . Moghanian and Araujo also confirmed the Sr substituted bioglass exhibited antibacterial effect against methicillin‐resistant Staphylococcus aureus bacteria 65,66 …”

“…In our study, the Mg‐Sc‐Sr discs displayed higher antibacterial activity and a lower corrosion rate when compared to Mg and Mg‐Sc discs. The mechanism by which Sr improves antibacterial properties is unknown 64‐67 . A potential reason for enhanced antibacterial properties of the Mg‐Sc‐Sr discs is alteration of the zeta potential on the alloy surface after addition of Sr to Mg alloy.…”

“…6,13,38,[61][62][63] To combat this reduction in antibacterial properties in Mg-Sc, we added Sr to improve antibacterial properties of the alloy. [64][65][66][67] Gao et al reported that the in vitro antibacterial tests on Mg-Sr-Ga alloy placed it on the top of the ranking list of germ-killing ability. Also, in vivo rat model of implantassociated femur osteomyelitis demonstrated inhibiting S. aureus on the surface of implanted rods.…”

Assessment of Environmental Factors Associated with Antibiotic Resistance Genes (ARGs) in the Yangtze Delta, China

“…Although negative correlation of strontium may be explained by its cytotoxicity on bacteria [42,43], molecular biology studies have reported selective inhibition effects of magnesium and calcium on antibiotic-resistant bacteria. Magnesium and calcium may involve directly in the destabilization of the Staphylococcus aureus cell membrane [44].…”