Acute and chronic stress-induced gastrointestinal injury in rats, and protection by a novel 1H636 grape seed proanthocyanidin extract (GSPE): [formula omitted], C.B. Williams, M. Milnes, J. Balmoori, X. Ye, D. Bagchi, S.J. Stohs, Creighton Univ. Health Sciences Center, Omaha, NE 68178

Abstract

Oxidative damage and apoptosis play dominant roles in the pathogenesis of steroid-induced osteonecrosis (ON). Grape seed proanthocyanidin extract (GSPE) demonstrates antioxidant and antiapoptotic properties. Our aim was to demonstrate the effects of GSPE in preventing steroid-induced ON in rabbits.Osteonecrosis was induced by high-dose methylprednisolone (40 mg/kg). Rabbits in the preventive medicine group were treated with 100 mg/kg/day GSPE for 14 consecutive days, and the presence or absence of ON was examined histopathologically. Oxidative damage in bone tissue was assessed by immunohistochemical staining of 8-oxo-2’-deoxyguanosine (8-OHdG), malondialdehyde (MDA) levels, and activities of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and phospholipid hydroperoxide glutathione peroxidase (GSH-Px). Apoptosis was detected via quantitative terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate nick end labelling (TUNEL) staining and activated caspase 3 immunoblotting and activity.GSPE significantly attenuated the changes of immunohistochemical staining of 8-OHdG, MDA levels, and antioxidant enzymes activities, which were caused by methylprednisolone administration. Quantitative TUNEL and caspase 3 assay showed lower apoptosis with GSPE application. Simultaneously, GSPE reduced the incidence of steroid-induced ON in an established rabbit model to 17.6 %, compared with 87.5 % in the steroid-only group.These results reveal that GSPE treatment could inhibit oxidative damage and apoptosis to exert beneficial effects on reducing the incidence of steroid-induced ON in rabbit models.