Samira Jebahi

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.

Haematological and biochemical toxicity induced by methanol in rats: ameliorative effects of Opuntia vulgaris fruit extract.

The ameliorative effects of Opuntia vulgaris fruit extract (OE) were evaluated against methanol-induced haematological and biochemical toxicity in rats. The methanol-induced haematological and biochemical perturbation significantly decreased the levels of red blood cell (RBC), haemoglobin (Hb), haematocrit (Ht), serum total protein and increased glucose, cholesterol, and triglyceride levels in serum. Treatment of rats with methanol significantly increased lipid peroxidation (LPO) level and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in erythrocytes. OE treatment could increase significantly the levels of RBC, Hb, Ht and total protein, and decrease glucose, cholesterol and triglyceride levels in serum, and increase the activities of SOD, CAT and GPx in erythrocytes, when compared with methanol-treated group. Spleen histopathology showed that OE could significantly reduce the incidence of spleen lesion induced by methanol. These results suggested that OE could exhibit a potential source of natural antioxidants against methanol-induced haematological and biochemical disruption in rats. The protective effects of OE may be due to the modulation of antioxidant enzymes activities and inhibition of LPO.

Chitosan-based bioglass composite for bone tissue healing : Oxidative stress status and antiosteoporotic performance in a ovariectomized rat model

Tissue engineering has opened up a new therapeutic avenue promising a revolution in regenerative medicine. Considerable attention has been given to chitosan composite materials and their applications in the field of the bone graft substitutes. We evaluated the antioxidative properties of chitosan-doped bioactive glass (BG-CH) with 17 wt% chitosan, and their applications in the guided bone regeneration. BG-CH was produced by a freeze-drying process and implanted in the femoral condyles of ovariectomized rats. Grafted bone tissues were carefully removed to evaluate the oxidative stress analysis, histomorphometric profile and mineral bone distribution by using inductively coupled plasma optical emission spectrometry (ICP-OES). A significant decrease of thiobarbituric acid-reactive substances (TBARs) was observed after BG-CH implantation. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities significantly increased in ovariectomized group implanted with chitosan-doped bioactive glass (OVXBG-CH) as compared to ovariectomized group implanted with bioactive glass (OVX-BG). The histomorphometric analysis showed that bone/tissue volume (BV/TV), osteoblast number (N.Ob) and osteoblast surface/bone surface (Ob.S/BS) were significantly higher in OVX-BG-CH group than in OVX-BG group. On the other hand, a rise in Ca and P ion concentrations in the implanted microenvironment was shown to lead to the formation/deposition of Ca-P phases. Trace elements such as Sr and Fe were detected in the newly formed bone and involved in bone healing. These results suggested that BG-CH composites could become clinically useful as a therapeutic and implantable material.

Effect of novel curcumin‐encapsulated chitosan–bioglass drug on bone and skin repair after gamma radiation: experimental study on a Wistar rat model

Radiation therapy contributes to a significant increase in bone osteoporosis and skin loss. Various natural health products might be beneficial to reduce bone and skin alterations. Curcumin (CUR) medicines derived from natural plants have played an important role in health care. This study aims at synthesizing and evaluating the performance therapy of CUR‐encapsulated bioglass–chitosan (CUR–BG–CH). In vitro, the antioxidant assay was evaluated by using 1,1‐diphenyl‐2‐picrylhydrazyl free‐radical (DPPH) scavenging and the nitroblue tetrazolium reduction. The CUR–BG–CH antimicrobial effects were tested in liquid media. In vivo, after rat 60Co γ‐radiation, the tissue wound‐healing process was studied by grafting CUR and CUR–BG–CH in femoral condyle and dorsal skin rat tissue. The antioxidant studies indicated that CUR–BG–CH quenches free radicals more efficiently than unmodified CUR and had effective DPPH (91%) and superoxide anion (51%) radical scavenging activities. The CUR–BG–CH biomaterial exhibited an important antimicrobial activity against Staphylococcus aureus. The histomorphometric parameters showed amelioration in CUR–BG–CH‐treated rats. An improved mechanical property was noticed (33.16 ± 5.0 HV) when compared with that of unmodified CUR group (23.15 ± 4.9 HV). A significant decrease in tumour necrosis factor‐α cytokine production was noted in the CUR–BG–CH rats (90 pg/ml) as compared with that of unmodified CUR group (240 pg/ml). The total amount of hydroxyproline was significantly enhanced (33.5%) in CUR–BG–CH group as compared with that of control. Our findings suggested that CUR–BG–CH might have promising potential applications for wound healing. Copyright

Biologic response to carbonated hydroxyapatite associated with orthopedic device: experimental study in a rabbit model.

Background Carbonated hydroxyapatite (CHA) and related calcium phosphates have been studied for many years as implant materials due to their similarity with the mineral phase of bone. The main limitation of CHA ceramics as well as other bioactive materials is that they have poor mechanical proprieties. It is thought that the mechanical device can cause an increase in metabolic activity and bone healing. In this study we investigated the reactivity and tissue behaviour of implanted CHA biomaterial reinforced by mini external fixator. Methods The evaluation of biomaterial biocompatibility and osteogenesis was performed on a rabbit model over a period of 6 weeks by radiological, histological and scanning electron microscopy (SEM) coupled with energy dispersive X-ray SEM-energy-dispersive X-ray (EDX) analysis. Results While rabbits treated with CHA exhibited more bone formation, and fibrous tissue was observed when empty bone defects were observed. EDX analysis detected little calcium and phosphorus on the surface of the bone that was not implanted, while high content of calcium (62.7%) and phosphorus (38%) was found on the interface bone cement. Conclusions Bone repairing showed that the mini external fixator stimulated the ossification which was pushed when grafted by CHA. This effect may play an important role in the prevention of implant loosening.

The potential restorative effects of strontium-doped bioactive glass on bone microarchitecture after estrogen-deficieny induced osteoporosis: Physicochemical and histomorphometric analyses

Strontium (Sr) compounds have become increasingly popular in the field of osteoporosis treatment. However, the quality of new bone after implantation of strontium-containing bioceramics has yet to be investigated. In the present study, the newly formed bone tissue around strontium-doped bioactive glass (BG-Sr) implants was characterized. BG-Sr was implanted in the femoral condyl of ovariectomised rats (OVX). The resected bone was prepared for analysis using several physico-chemical and biological assays such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, and histomorphometry. BG-Sr biomaterial favored calcium phosphate layer integration on the surface of the glass and offered better bioactivity. Moreover, the histomorphometric analysis demonstrated that BV/TV, N. Ob were significantly higher in BG-Sr treated rats groups than those of BG groups. However, Ob. S/BS, and OV/BV were significantly lower in BG-Sr treated rats groups than those of BG groups. The (Oc.S/BS) was significantly decreased in BG-Sr groups, when compared with that of BG rat groups. On the other hand, the MS/BS had not significantly decreased in the BG-Sr treated rats groups when compared with that of BG groups, however; it was significantly higher when compared with control and OVX groups. These findings suggest that BG-Sr can be used as an inhibitory therapeutic potential of osteoporosis by delivering strontium to stimulate new bone remodeling.