The influence of Sr doses on the in vitro biocompatibility and in vivo degradability of single‐phase Sr‐incorporated HAP cement

Abstract

In previous studies, we developed a new type of Sr-incorporated hydroxyapatite cement (Sr-HAC), which was shown to have many excellent physiochemical properties, by an ionic cement route (Guo et al., Biomaterials 2005;26:4073-4083). As a further study, the main aims of this article were to examine the Sr-HAC's in vitro biocompatibility, including acute toxicity, hemolytic reaction, pyrogen reaction, and cytoxicity, to evaluate its in vivo degradability during intramuscular and femur implantation, and also to investigate the influence of Sr doses on these properties. The in vitro results show that all of the Sr-HAC samples exhibit satisfactory biocompatibility, and the Sr/(Sr+Ca) molar ratio has an important effect on these properties. For example, the Sr-HAC with a Sr/(Sr+Ca) molar ratio of 5% (5% Sr-HAC) has higher biocompatibility than both the one with a Sr/(Sr+Ca) molar ratio of 10% (10% Sr-HAC) and the Sr-free one. The in vivo results of both the rabbit intramuscular and femur implantation experiments show that the Sr-HAC samples exhibit a much faster degradation rate than the Sr-free one, and that this also depends on the Sr/(Sr+Ca) molar ratio. Specifically, the mean degradation rate of the 10% Sr-HAC increases by an amplitude of 73.9 wt % compared with that of the Sr-free HAC. In addition, the optical transmission photographs show that the Sr doses play an important role on the interface between the implants and the new bone. The energy dispersion X-ray spectrum analysis indicates that there exists a gradient distribution of Sr element in the tight and bioactive interface between the implants and new bone, indicating that the Sr element takes a share in the mineralization of the new bone together with Ca element.

Histomorphometric evaluation of strontium-containing nanostructured hydroxyapatite as bone substitute in sheep

“…These results contradict the findings of Dagang et al, 32 who evaluated a strontium-containing HA cement and showed that it had better osteoconductivity, biocompatibility and biodegradability than HA-only cement. Biocompatibility testing performed by these authors revealed that the 5% strontium-containing …”

In vivo and clinical application of strontium-enriched biomaterials for bone regeneration

“…36,37 However, two of the three authors who specifically compared different Sr percentages found an increased overall response with higher concentrations, 24,34 confirming previous in vitro reports. 52 The other author reported similar results between E and C. 28 All three authors agree that the optimum dose of Sr is yet to be discovered, since it can impact both the bone response and material properties.…”

“…52 The other author reported similar results between E and C. 28 All three authors agree that the optimum dose of Sr is yet to be discovered, since it can impact both the bone response and material properties. 24,28,34 …”

An emerging pollutant contributing to the cytotoxicity of MSWI ash wastes: Strontium

“…Although these results suggest that the Sr leaching behavior was related to the pH, we are unable to provide a plot of the solubility of strontium hydroxide with respect to the pH. Many literature reports have described the cytotoxicity of Sr and its compounds [22][23][24][25]. Keller reported that 89 Sr could suppress the spontaneous cytotoxicity in mouse tissues [22].…”

“…Keller reported that 89 Sr could suppress the spontaneous cytotoxicity in mouse tissues [22]. In recent years, Sr-incorporated hydroxyapatite cement [23] and calcium phosphate cement [24] have been developed as new biomedical materials, which exhibit good compatibility and low cytotoxicity, for use in human bones. An in vitro test revealed that strontium ranelate is non-toxic toward human periodontal ligament fibroblasts [25].…”