Detoxification of rats subjected to nickel chloride by a biomaterial-based carbonated orthophosphate.

Recently, the therapeutic approaches of the detoxification against the metals (nickel) in the body are the use of biomaterials such as carbonated hydroxyapatite. The aim of this study is therefore to analyze the physiological and physicochemical parameters of strain white rats "Wistar" receiving nickel chloride and to study the protective associative of apatite against adverse effects of this metal, and this in comparison with control rats. Our results showed that the nickel induced in rats an oxidative stress objectified by elevated levels of thiobarbituric acid-reactive substances and conjugated dienes associated with inhibition of the activity of the antioxidant defense system such as glutathione peroxidase, superoxide dismutase and catalase in the liver, kidney, spleen and erythrocyte. Disorders balances of ferric, phosphocalcic, a renal failure and a liver toxicity were observed in rats exposed to nickel. As well as a significant increase in the rate of nickel in the bones and microcytic anemia was revealed. However, the implantation of carbonated hydroxyapatite in capsule form protects rats intoxicated by the nickel against the toxic effects of this metal by lowering the levels of markers of lipid peroxidation and improving the activities of defense enzymes. Our implantation technique is effective to correct ferric balance and phosphocalcic equilibrium, to protect liver and kidney function, to reduce the rate of bone nickel and to correct anemia. They clearly explain the beneficial and protective of our biomaterial which aims the detoxification of rats receiving nickel by substituting cationic (Ca(2+) by Ni(2+)) and anionic (OH(-) by Cl(-)) confirmed by physicochemical characterization like the IR spectroscopy and X-ray diffraction. These techniques have shown on the one hand a duplication of OH(-) bands (IR) and on the other hand the increase of the volume of the apatite cell after these substitutions (X-ray diffraction).

Biological therapy of strontium-substituted bioglass for soft tissue wound-healing: responses to oxidative stress in ovariectomised rats.

New synthetic biomaterials are constantly being developed for wound repair and regeneration. Bioactive glasses (BG) containing strontium have shown successful applications in tissue engineering account of their biocompatibility and the positive biological effects after implantation. This study aimed to assess whether BG-Sr was accepted by the host tissue and to characterize oxidative stress biomarker and antioxidant enzyme profiles during muscle and skin healing. Wistar rats were divided into five groups (six animals per group): the group (I) was used as negative control (T), after ovariectomy, groups II, III, IV and V were used respectively as positive control (OVX), implanted tissue with BG (OVX-BG), BG-Sr (OVX-BG-Sr) and presented empty defects (OVX-NI). Soft tissues surrounding biomaterials were used to estimate superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) concentration. Our results show that 60 days after operation, treatment of rats with BG-Sr significantly increased MDA concentration and caused an increase of SOD, CAT and GPx activities in both skin and muscular tissues. BG-Sr revealed maturation of myotubes followed a normal appearance of muscle regenerated with high density and mature capillary vessels. High wound recovery with complete re-epithelialization and regeneration of skin was observed. The results demonstrate that the protective action against reactive oxygen species (ROS) was clearly observed in soft tissue surrounding BG-Sr. Moreover, the potential use of BG-Sr rapidly restores the wound skin and muscle structural and functional properties. The BG advantages such as ion release might make BG-Sr an effective biomaterial choice for antioxidative activity.

Carbonate ions in apatites: infrared investigations in the upsilon 4 CO3 domain.

Fourier transform infrared (IR) spectroscopic investigations of precipitated carbonate apatites in the upsilon 4 CO3 domain reveal the existence of five bands at 757, 740, 718, 692, 670 cm-1 which can be assigned to several distinct environments of the carbonate ion in the apatite structure. In order to identify these environments precisely, fluoridated and pure type A carbonate apatites (i.e., with carbonate ions in monovalent anionic sites) were examined. The bands at 670 and 757 cm-1 were attributed to type A carbonate and their relative intensity was found to increase when the carbonate content of the apatite diminished or when samples were heated at 400 degrees C. Fluoridated apatites show only two bands, close to 718 and 692 cm-1, corresponding to type B carbonate ions (carbonate in trivalent anionic sites). The band at 740 cm-1 was revealed by heating the samples to 400 degrees C. This is due to OH ions' hydrogen bonded to fluoride and to carbonate ions in an undetermined apatite site. Despite the low intensity of IR bands, investigations in the upsilon 4 CO3 domain appear complementary to those in other carbonate vibrational domains and could be useful for a more precise identification of bone mineral.