Influence of nanostructured calcium aluminate and calcium silicate on the liver: histological and unbiased stereological analysis

Abstract

Aim To examine the potential systemic toxicity of nanostructured materials based on calcium silicate and calcium aluminate, for potential application in Dentistry. Methodology Twenty‐four Albino Wistar rats aged 2 months were used as an in vivo animal model for subcutaneous implantation of the investigated materials, placed in polyethylene tubes. Thirty days after implantation, the livers of the rats were analysed and following histological and stereological parameters were evaluated for volume density of hepatocytes and blood sinusoids, number and numerical density of hepatocytes, surface of hepatocytes and their nucleuses, nucleocytoplasmic ratio and mitotic index of hepatocytes. Stereological measurements were achieved using Cavalieri's principle, with grid P2 and unbiased analysis. Additionally, immunohistochemistry studies were performed to further analyse changes in liver tissue. Several haematological and biochemical parameters of blood of experimental animals were also analysed, as well as local tissue reactions around the implants. Statistical analysis was performed using parametric (anova and t‐test) and nonparametric tests (Kruskal–Wallis and Mann–Whitney U‐test) depending on data distribution. Results Implanted dental cements led to an increase in stereological and histological parameters in liver tissue compared to control rats. Although the investigated parameters mostly showed significant differences between control and experimental animals, the liver tissue of the experimental animals did not have visible signs of pathological changes. This was supported by the analysis of blood parameters which were not significantly different between control and experimental animals. Also, the subcutaneous tissues had minimal inflammatory reactions. Immunohistochemistry studies revealed that nanostructured materials induced proliferation of hepatocytes, but that the immunological response to the materials was not strong enough to induce proliferation of immunoreactive cells in liver in the observed time period. Conclusions This study was performed as a contribution to the attestation of the biocompatibility of dental cements based on calcium silicate and calcium aluminate. Although these materials induced several changes in the liver structure, they were not clinically relevant and represent a normal and reversible response of the liver to the presence of biocompatible materials in the body. Blood and immunohistochemistry analyses and local tissue reactions further confirmed that these materials possess good biocompatible potential.

Toxicological Profile of Nanostructured Bone Substitute Based on Hydroxyapatite and Poly(lactide-co-glycolide) after Subchronic Oral Exposure of Rats

“…It was concluded that materials induced normal and reversible response in the liver. Namely, the proliferation of parenchymal cells in this case was also reported, with no visible signs of pathological changes or immunological reaction to the materials [32].…”

“…In our previous study, the effect of calcium silicate and calcium aluminate implantation on systematic subchronic toxicity was evaluated [32]. It was concluded that materials induced normal and reversible response in the liver.…”

Physico-chemical and biological properties of dental calcium silicate cements - literature review

“…Also, an experimental CS-HAP cement implanted subcutaneously in rats has induced a low inflammatory reaction of the tissue over the same period of time, which was lower than that of ProRoot MTA [81]. In addition, a nanostructured CS mixture did not show any negative effect on liver in rats after thirty days of oral administration [82]. Pulp capping in this animal model revealed statistically significantly lower inflammatory reaction of CS samples, in comparison to the Super-EBA (Keystone Ind., Muerstown, Pensilvania, USA) and ProRoot MTA.…”

Biocompatibility Study of a New Dental Cement Based on Hydroxyapatite and Calcium Silicates: Focus on Liver, Kidney, and Spleen Tissue Effects

“…The results showed that using materials induced normal and reversible response in the liver. Namely, investigated proliferation rate with the average number of immunoreactive Ki67 positive parenchymal cells was also reported, with no visible signs of pathological changes or immunological reaction to the materials [ 42 ].…”