The effect of zymosan and the protective effect of various antioxidants on fracture healing in rats.

AIM: To investigate the effects of free oxygen radicals and various antioxidants on bone healing after experimental formation of fracture. MATERIALS AND METHODS: Fifty male rats were used and divided into five groups (ten rats in each). The right forelimbs of the rats were broken by bimanual compression method. One hour before this procedure, 5 ml/kg of intraperitoneal (i.p.) physiologic saline were given to the control Group 1. All 40 rats in the experimental Groups 2, 3, 4 and 5 were treated with i.p. zymosan at a dosage of 100 mg/kg to induce the production of free radicals by stimulating NADPH oxidase in polymorphonuclear leukocytes. Zymosan induction was stopped on the fifth post-fracture day. In addition to the zymosan, i.p. 1 g/kg/day of dimethyl sulfoxide were given to the animals in Group 3, 50 mg/kg/d of Ginko biloba Extract (EGb 761) in Group 4 and 500 mg/kg/day of vitamin C in Group 5. Radiographs of the fractures of all animals were obtained to assess callus formation, remodeling and bridging bone formation under ether anesthetics on postfracture day 7, 14 and 21. All rats were euthanized on day 22, and sections of the radius and ulna were examined both histologically with light and electron microscopy and ultrastructurally. Statistical analysis was made with Kruskal-Wallis variance analyze test and comparison between groups was performed by Dunn's multiple comparison test. RESULTS: An impairment of bone healing was observed in Group 2 inducted with purely zymosan. Variable results were obtained for bone healing in the groups treated with various antioxidants. There was very significant difference of fracture healing between Groups 1 and 2 both histologically and radiologically (P < 0.001). There was significant difference between Groups 2 and 5 radiologically (P < 0.05). CONCLUSION: Free oxygen radicals demonstrate a negative effect on fracture healing and vitamin C (an antioxidant) partially prevents the negative effect of zymosan on fracture healing.

Amelioration of aluminium-induced liver damage by vitamin E.

OBJECTIVE: To investigate the effects of aluminium sulphate on the microscopic morphology of the liver and on vitamin E amelioration of aluminium-induced liver damage. METHODS: Rats were injected intraperitoneally with aluminium sulphate alone or aluminium sulphate together with vitamin E, with saline injected rats used as the control group. The study took place in Pamukkale University Faculty of Medicine in 2005. RESULTS: The rats exposed to aluminium showed morphological changes in addition to previously reported biochemical changes in the liver. The anti-oxidant vitamin E significantly diminished the liver damage seen due to aluminium. CONCLUSION: There is an apparent protective effect of vitamin E on parenteral aluminium exposure.