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.

Inhibitory effects of Zinc on hyperglycaemia and metabolic disorders in the liver of alloxan-induced diabetic rats

Background: Zinc may participate as a component of the antioxidant defense system. Its deficiency induces oxidative damage to cell components and alterations in antioxidants enzymes in both animal and cells models. There are few studies to provide evidence of the action of zinc in diabetic animal models. Objective: To evaluate the action of oral administration of zinc (Zn) in hyperglycemia and metabolic disorders induced in the liver of alloxan-induced diabetic rats. Materials and method: Wistar rats (age: two months) were used for this study. Inducing diabetes in rats using alloxan, we obtained the diabetic rats after four weeks. The rats were divided into five groups (each n=8): normal (control) rat, diabetic rats before the beginning of treatment (Diab-ref), diabetic rats at the end of the treatment (Diab-Con), diabetic rats treated with zinc gluconate (Diab+Zn), and diabetic rats treated with insulin (Diab+Ins). Zinc was orally administrated in drinking water at dose 150mg/L, and insulin was administrated at 0.5IU/rat/day. Thiobarbituric acid-reactive substances (TBARS) superoxide dismutase (SOD), glutathione peroxidise (GPX), catalase (CAT), transaminase glutanic pyruvic (TGP), transaminase glutanic oxaloacetic (TGO), total bilirubin, total cholesterol (TCh), triglyeerides (TG), high density lipid-cholesterol (HDL-Ch), plasmatic, and liver glucose were determined in blood and liver samples. Results: Zn administration significantly decreased glucose level and glycogen content. Activities of SOD, CAT and GPO were significantly increased by Zn-treatment. In addition, the liver toxicity was prevented by significantly lowering in total bilirubin, TARSs, TGP, and TPO. Conclusion: Zinc supplements may be beneficial for correcting hyperglycemia leading to diabetic complications in the liver.

Protective effects of estrogens and caloric restriction during aging on various rat testis parameters / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To investigate the effects of 17beta-estradiol (E2), Peganum harmala extract (PHE) and caloric restriction (CR) on various testis parameters during aging.</p><p><b>METHODS</b>Twelve month-old male rats were treated for 6 months with either E2 or PHE, or submitted to CR (40%).</p><p><b>RESULTS</b>Our results show that estrogens and CR are able to protect the male gonad by preventing the decrease of testosterone and E2 levels as well as the decrease of aromatase and estrogen receptor gene expressions. Indeed, E2, PHE and CR treatments induced an increase in the superoxide dismutase activities and decreased the activity of testicular enzymes: gamma-glutamyl transferase, alkaline phosphatase, lactate deshydrogenase as well as the aspartate and lactate transaminases in aged animals. In addition, the testicular catalase and gluthatione peroxidase activities were enhanced in E2, PHE and CR-treated rats compared to untreated animals at 18 months of age. Moreover, the positive effects of estradiol, PHE and CR were further supported by a lower level of lipid peroxidation. Recovery of spermatogenesis was recorded in treated rats.</p><p><b>CONCLUSION</b>Besides a low caloric diet which is beneficial for spermatogenesis, a protective antioxydant role of estrogens is suggested. Estrogens delay testicular cell damage, which leads to functional senescence and, therefore, estrogens are helpful in protecting the reproductive functions from the adverse effects exerted by reactive oxygen species (ROS) produced in large quantities in the aged testis.</p>