Didem Bacanli

Comparison of the protective effects of melatonin and amifostine on radiation-induced epiphyseal injury.

Purpose: We compared the effects of amifostine and melatonin in preventing radiation-induced epiphyseal growth plate injury in rats. Materials and methods: Four-week-old (65–85 g), growing male Sprague-Dawley rats were randomly assigned to receive radiation alone, at 25 Gy in three fractions (group R), or this dose of fractionated radiation proceeded by prophylactic amifostine 200 mg/kg i.p. (group A), melatonin 15 mg/kg i.p. (group M), or amifostine + melatonin (group AM). The right rear extremity of each animal was irradiated while the contralateral leg was shielded from radiation, as a control. Bone growth based on the length of the tibia, femur, and overall limb was calculated 6 weeks after the treatment. Results: In groups R, A, M, and AM, the mean growth loss (GL) for the overall limb was 56.9 ± 8.1%, 46.8 ± 7.7%, 36.6 ± 4.3%, and 38.5 ± 5.1%, respectively. The limb length discrepancies (LLD) in groups R, A, M, and AM were 13.8 ± 1.4%, 10.5 ± 0.3%, 7.4 ± 0.7%, and 8.8 ± 1.1%, respectively. Differences in LLD were significant between each treatment group and group R (range: p = 0.0001–0.001). Differences in either of mean GL and LLD were not significant between groups M and AM; however both of these groups had significantly less GL and LLD than group A. Conclusions: We observed a superior radioprotective function of melatonin over amifostine in preventing radiation-induced epiphyseal growth plate injury, without any increase in radioprotective effect by adding amifostine to melatonin.

The effect of oophorectomy on epidural fibrosis after laminectomy: an experimental study in rats.

OBJECTIVE The aim of this study was to examine the effect of oophorectomy in the formation of epidural fibrosis in a rat laminectomy model. METHODS Thirty-six 12-month-old adult female Sprague-Dawley rats were used in this study. Rats were evenly divided into two groups; oophorectomized and sham-operated. Bilateral oophorectomy was performed on the 18 rats in the oophorectomized group. Three weeks after oophorectomy, rats in both groups underwent complete bilateral laminectomy at the L2 and L3 vertebral levels. Rats were divided into 3 equal groups and sacrificed in groups of 4 at the 4th, 8t, and 12th weeks postoperatively and the lumbar spine excised en bloc, fixed and decalcified. Sections were stained with hematoxylin and eosin and Massons trichrome were used to evaluate epidural fibrosis, acute inflammation, chronic inflammation, and vascular proliferation. RESULTS The mean histological sum grade of the epidural fibrosis was greater in the oophorectomized group (p>0.05). CONCLUSION Endogenous estrogen could have an effect on epidural fibrosis formation after lumbar laminectomy in rats.

Radiological and Histological Evaluation of the Effects of Cortical Perforations on Bone Healing in Mandibular Onlay Graft Procedures

BACKGROUND Perforations of the cortical bone may be an advantage for the success of the autogenous bone graft procedure, but whether this perforation has a positive effect on the bone remains controversial. PURPOSE This study evaluates the effects of cortical perforation of the autogenous bone block graft radiologically and histologically. MATERIALS AND METHODS Seven adult pigs were used for this study. On the experimental side, cortical perforation at the host site was prepared, while no perforation was done on the control side. The specimens were evaluated, and the Wilcoxon signed-rank test was used for statistical analysis. RESULTS In the radiological evaluation, the Wilcoxon signed-rank test indicated no significant differences in densities among the grafts (p = .23) with a mean of 4.29 ± 0.951 for the unperforated graft side and 3.57 ± 0.976 for the decorticated graft side. In histological evaluation, there was a significant difference in the thickness of the grafts between the groups (experimental group 3.71 ± 1.286, control group: 4.71 ± 0.488; p = .033). However, when the remodeling and osteoblastic activity in the grafts were measured, no significant differences were observed between the groups (p = 1 and p = .133, respectively). CONCLUSION In augmentation with mandibular onlay bone grafts, cortical perforations in the recipient site make no distinct contribution to bone healing within 12 weeks.

Antiproliferative and anti-apoptotic effect of astaxanthin in an oxygen-induced retinopathy mouse model

OBJECTIVE To evaluate the impact of intravitreal (IV) and intraperitoneal (IP) astaxanthin (AST) injections on neovascular development (ND), retinal morphology, and apoptotic activity in a C57BL/6J mouse model with hyperoxia-induced retinopathy (HIR). DESIGN C57BL/6J mouse model. METHODS Two negative control groups (n = 6 each; one of which received IV sterile dimethyl sulfoxide [DMSO]) of C57BL/6J-type mice were exposed to room air. The HIR groups included 36 C57BL/6J-type mice exposed to 75% ± 2% oxygen from postnatal day (PD) 7 to PD 12. On PD 12, these mice were randomized into 6 groups (n = 6 each): 2 HIR control groups (one of which received IV-DMSO), 2 IV-AST groups (10 and 100 µg/mL), and 2 IP-AST groups (0.5 and 5 mg/kg). We measured ND by counting neovascular tufts in cross sections and examined histological, ultrastructural changes via light and electron microscopy. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated nick end-labeling. RESULTS No ND was detected in the negative control groups. ND levels were not significantly different between high- and low-dose AST for either means of administration. However, ND levels were significantly lower in the AST groups, regardless of delivery, compared to the control groups. The means of delivery (IP versus IV) also yielded significant differences in ND. The incidence of mitochondrial dysmorphology and apoptosis were lower in groups receiving AST. CONCLUSIONS AST seems to suppress ND and has anti-apoptotic activity in the HIR mouse model.