Oxidative stress and antioxidant responses of liver and kidney tissue after implantation of titanium or titanium oxide coated plate in rat tibiae

Mitochondrial Redox Balance of Fibroblasts Exposed to Ti-6Al-4V Microplates Subjected to Different Types of Anodizing

Despite the high biocompatibility of titanium and its alloys, the need to remove titanium implants is increasingly being debated due to the potential for adverse effects associated with long-term retention. Therefore, new solutions are being sought to enhance the biocompatibility of titanium implants. One of them is to increase the thickness of the passive layer of the implant made of titanium dioxide. We were the first to evaluate the effect of hard-anodized (type II) Ti-6Al-4V alloy discs on the cytotoxicity, mitochondrial function, and redox balance of fibroblasts mitochondria compared to standard-anodized (type III) and non-anodized discs. The study used fibroblasts obtained from human gingival tissue. The test discs were applied to the bottom of 12-well plates. Cells were cultured for 24 h and 7, 14, and 21 days and mitochondria were isolated. We demonstrated the occurrence of oxidative stress in the mitochondria of fibroblasts of all tested groups, regardless of the presence and type of anodization. Type II anodization prevented changes in complex II activity (vs. control). The lowest degree of citrate synthase inhibition occurred in mitochondria exposed to titanium discs with type II anodization. In the last phase of culture, the presence of type II anodization reduced the degree of cytochrome c oxidase inhibition compared to the other tests groups and the control group, and prevented apoptosis. Throughout the experiment, the release of titanium, aluminium, and vanadium ions from titanium discs with a hard-anodized passive layer was higher than from the other titanium discs, but decreased with time. The obtained results proved the existence of dysfunction and redox imbalance in the mitochondria of fibroblasts exposed to hard-anodized titanium discs, suggesting the need to search for new materials perhaps biodegradable in tissues of the human body.

The Redox Balance in Erythrocytes, Plasma, and Periosteum of Patients with Titanium Fixation of the Jaw

Titanium miniplates and screws are commonly used for fixation of jaw fractured or osteotomies. Despite the opinion of their biocompatibility, in clinical practice symptoms of chronic inflammation around the fixation develop in some patients, even many years after the application of miniplates and screws. The cause of these complications is still an unanswered question. Taking into account that oxidative stress is one of the toxic action of titanium, we have evaluated the antioxidant barrier as well as oxidative stress in the erythrocytes, plasma and periosteum covering the titanium fixation of the jaw. The study group was composed of 32 patients aged 20–30 with inserted miniplates and screws. The antioxidant defense: catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase-1 (SOD1), uric acid (UA), total antioxidant capacity (TAC), as well as oxidative damage products: advanced oxidation protein products (AOPP), advanced glycation end products (AGE), dityrosine, kynurenine, N-formylkynurenine, tryptophan, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), total oxidant status (TOS), and oxidative status index (OSI) were evaluated. SOD1 activity (↓37%), and tryptophan levels (↓34%) showed a significant decrease while AOPP (↑25%), TOS (↑80%) and OSI (↑101%) were significantly elevated in maxillary periosteum of patients who underwent bimaxillary osteotomies as compared to the control group. SOD-1 (↓55%), TAC (↓58.6%), AGE (↓60%) and N-formylkynurenine (↓34%) was statistically reduced while AOPP (↑38%), MDA (↑29%), 4-HNE (↑114%), TOS (↑99%), and OSI (↑381%) were significantly higher in the mandibular periosteum covering miniplates/screw compared with the control tissues. There were no correlations between antioxidants and oxidative stress markers in the periosteum of all patients and the blood. As exposure to the Ti6Al4V titanium alloy leads to disturbances of redox balance in the periosteum surrounding titanium implants of the maxilla and the mandible so antioxidant supplementation should be recommended to the patients undergoing treatment of dentofacial deformities with the use of titanium implants. The results we obtained may also indicate a need to improve the quality of titanium jaw fixations through increase of TiO₂ passivation layer thickness or to develop new, the most highly biodegradable materials for their production.

Hormonal and organ-specific dysfunction induced by the interaction between titanium dioxide nanoparticles and salicylic acid in male mice

BACKGROUND

Nanomaterials coating gained much concern in orthopedic implants and cosmetics. Drug combination may be a promising strategy for treating multi-factorial diseases. Titanium dioxide (TDN) nanoparticles are being widely used in many industries as well as in medicine and pharmacology. Therefore, increased human and environmental exposure can be expected, which has put TDN under toxicological scrutiny, and it is necessary to address the potential health and safety implications of nanomaterials used in nanomedicine. The toxicity of titanium oxide nanoparticles (TDN) and salicylic acid (SA) separately or in combination was studied for 21 days.

METHODS

The liver and kidney biomarker were determined, and hormones and oxidative stress levels were detected in mice.

RESULTS

The intraperitoneal (i.p.) injection of TDN and SA in combination had a potential toxicological effect on major organs and hormonal homeostasis of mice. TDN and SA could antagonistically interact to affect the liver and kidney functions. No synergistic damage was observed in the liver function of mice that were treated with both TDN and SA as compared to the SA group. TDN acted as a synergistic agent to SA in the case of total cholesterol and total proteins levels. SA acted as antagonistic to the effect of TDN when injected together in mice because the effect on kidney functions is less than that predicted on the basis of the additive. The effect of co-administration of SA and TDN on the following hormones; triiodothyronine, thyroxine, estradiol II and insulin various among additive, potentiation, antagonistic and no effect, respectively as compared to TDN group. The interaction of TDN and SA was also found to induce oxidative stress as indicated by the increase in lipid peroxidation (LPO) levels. The decrease in the level of the reduced glutathione in the co-treated group indicated that there were no synergistic damages. SA and TDN co-administration could induce a potential increase in LPO levels in liver, kidney, and spleen but not in heart tissue. These results have not suggested that TDN and SA have a synergistic sub-chronic toxicity in mice after i.p. administration. SA may decrease the toxicity of TDN to some degree that could be related to the potentiation chemical reaction between SA and TDN.

CONCLUSIONS

Our results suggested that the damage observed in mice treated with TDN and SA is organ-specific and associated with hormonal homeostasis and oxidative damage.