Savas Aktas

Effectiveness of the biophysical barriers on the peridural fibrosis of a postlaminectomy rat model: An experimental research

PURPOSE Long term results after surgical treatment of disc herniation have shown that epidural and/or peridural fibrosis formed during the healing process after surgical intervention. We conducted this experimental study to evaluation of the effectiveness of the bioresorbable barriers (ADCON-L and Seprafilm(®) Adhesion Barrier) on formation of the peridural fibrosis in rat model performed laminectomy. METHODS Thirty-two male Wistar albino rats 250-350g body weight were distributed into three groups (CONTROL, AL group received ADCON-L; SAB group received Seprafilm(®) Adhesion Barrier). A dorsal laminectomy at L3, L4, L5 was performed, and then except those of the CONTROL group, the experimental material was left on the dura mater. Six weeks later spinal column of all rats was totally removed between the T10 and L5 levels, and peridural fibrosis, and dural adhesions were evaluated histologically and graded. The results were compared statistically by using the chi-square (χ(2)) test. Also three random regions were examined, and the fibroblast cells were counted. The fibroblast count results were statistically analysed by using the One-Way ANOVA test. RESULTS The variation of histopathological grades was statistically significant regarding the comparison of the all groups obtained from the χ(2) test (χ(2)=16.40; p=0.003). However, the variation in the mean values of the fibroblast count result was not statistically significant obtained from the One-Way ANOVA test (F=2.114; p>0.05). CONCLUSION Our study results suggest that Seprafilm(®) Adhesion Barrier and ADCON-L can be effective in reducing the prevalence of the postoperative peridural adhesions in rat laminectomy model. On the other hand, the fibroblast densities of the experimental groups were not different between groups. So, we could say that these materials can act as a foreign body in long term period in rat.

Alcohol-induced lung damage and increased oxidative stress.

Background: Alcohol-induced lung damage may be associated with increased oxidative stress. Objective: Our aim was to investigate alcohol-induced changes in the biochemistry and histopathology of the lung. Methods: Rats were divided into two groups, a control group and an ethanol group. The ethanol group received 2 g/kg ethanol (total: 3 ml) intraperitoneally. The controls were given the same amount of saline via the same route. Three hours later, the rats were sacrificed, and blood and lung tissue samples were obtained. Oxidative stress was assessed by measuring the levels of erythrocyte reduced glutathione (GSH), tissue malondialdehyde (MDA), myeloperoxidase (MPO) and Na+-K+ ATPase. Histopathologic evaluation of the lung tissues was also performed. Results: In the ethanol group, serum and tissue MDA levels and MPO activities were increased (p = 0.007, p = 0.001 and p = 0.000), and lung tissue Na+-K+ ATPase activities and erythrocyte GSH were decreased (p = 0.001 and p = 0.000) compared to the controls. Histopathologic examination demonstrated alveolocapillary thickening, alveolar degeneration, leukocyte infiltration and erythrocyte extravasation in the lungs of the ethanol group (p < 0.05). Conclusion: These results suggest that high-doseacute alcohol administration aggravates systemic and local oxidative stress leading to acute lung injury, ranging from mild pulmonary dysfunction to severe lung injury. It should be borne in mind that rapid onset of the acute respiratory distress syndrome (ARDS) may also be due to increased oxidative stress following alcohol abuse, especially when ischemic disturbances, e.g. coronary heart disease, acute ischemia of the extremities and traumatic accidents, are concomitantly present. Therefore, precautions against ARDS may prevent morbidity and mortality in alcohol-induced lung damage in at-risk patients.

Effects of ozone therapy on facial nerve regeneration

INTRODUCTION Ozone may promote moderate oxidative stress, which increases antioxidant endogenous systems. There are a number of antioxidants that have been investigated therapeutically for improving peripheral nerve regeneration. However, no previous studies have reported the effect of ozone therapy on facial nerve regeneration. OBJECTIVE We aimed to evaluate the effect of ozone therapy on facial nerve regeneration. METHODS Fourteen Wistar albino rats were randomly divided into two groups with experimental nerve crush injuries: a control group, which received saline treatment post-crush, and an experimental group, which received ozone treatment. All animals underwent surgery in which the left facial nerve was exposed and crushed. Treatment with saline or ozone began on the day of the nerve crush. Left facial nerve stimulation thresholds were measured before crush, immediately after crush, and after 30 days. After measuring nerve stimulation thresholds at 30 days post-injury, the crushed facial nerve was excised. All specimens were studied using light and electron microscopy. RESULTS Post-crushing, the ozone-treated group had lower stimulation thresholds than the saline group. Although this did not achieve statistical significance, it is indicative of greater functional improvement in the ozone group. Significant differences were found in vascular congestion, macrovacuolization, and myelin thickness between the ozone and control groups. Significant differences were also found in axonal degeneration and myelin ultrastructure between the two groups. CONCLUSION We found that ozone therapy exerted beneficial effect on the regeneration of crushed facial nerves in rats.

Electrophysiological, biochemical and ultrastructural effects of radiotherapy on normal rat sciatic nerve.

Abstract Purpose: The aim of the present study was to evaluate the electrophysiological, biochemical and ultrastructural changes on the rat sciatic nerve after radiotherapy. Material and Methods: Thirty male Wistar albino rats were divided into three groups as: Control group (n = 10), Group I: 3 months after radiotherapy (n = 10), and Group II: 6 months after radiotherapy (n = 10). Groups I and II were irradiated with a 60Co gamma source. A dose of 20 Gy in 10 fractions was applied to Groups I and II. Compound motor action potentials (CMAP) were recorded in all groups. Superoxide dismutase (SOD) and catalase (CAT) activities and malondialdehyde (MDA) levels were measured in the sciatic nerve of rats using the biochemical methods. Ultrastructural changes were determined by electron microscopy. Results: In Groups I and II, the amplitude of CMAP was significantly lower and the latency was significantly higher than that of the control group. There were no significant differences between Groups I and II regarding the CMAP amplitude and latency. The MDA levels were significantly increased, whereas the SOD and CAT activities were significantly decreased in experimental groups when compared with the control group. However, there were no significant changes in these parameters between Groups I and II. Degeneration in myelinated nerve fibers was observed ultrastructurally only in the experimental groups. Significant changes were observed between the control group and experimental groups in terms of ultrastructural myelin grading score and axonal damage score. No significant differences were found between Groups I and II. Conclusions: These findings indicated that the dose of 20 Gy in 10 fractions radiotherapy caused neuropathic damages in normal rat sciatic nerve 3 and 6 months after irradiation.

Is mycophenolate mofetil an alternative agent to corticosteroids in traumatic nerve paralysis

Objective The effects of an immunosuppressive agent, mycophenolate mofetil (MM), were investigated and compared with those of methylprednisolone (MP) and dexamethasone (DXM) on the traumatic nerve function. Study Design This is a randomized controlled animal study. Materials and Methods This experimental study was performed on 84 male Wistar albino rats. The rats were assigned to 12 groups each consisting of 7 animals. The groups were formed according to application of normal-dose DXM (group 1A-B), high-dose MP (group 2A-B), normal-dose MP (group 3A-B), MM (group 4A-B), and MM with high-dose MP combination therapies (group VA-B). Right sciatic nerve dissection was performed, and compound muscle action potential thresholds were recorded. The nerve was traumatized with the compression of a Jeweller forceps for 20 seconds. Posttraumatic thresholds were also recorded. The compound muscle action potential thresholds were recorded in the first and fourth weeks for the assigned groups. Then, the nerve was transected and prepared for electron microscopic and histopathologic examinations. Nitric oxide and malondialdehyde assessments were performed on both tissue and blood samples. Results Only the MM and MP+MM groups had satisfactory electron microscopic findings and were about to reach the tissue characteristics of the control animals. Despite the electrophysiologic recovery, the DXM group was found to have poor electron microscopic scoring. Conclusions Mycophenolate mofetil has been found to be beneficial in the treatment of traumatic nerve paralysis. Although a complementary investigation is needed, this immunosuppressive agent may be an alternative to corticosteroids for the selected cases where steroid therapy is contraindicated.

Comparison of bony healing and cartilage degeneration following strut grafting and trapdoor procedures in an ovine model.

This experimental study compared bony healing and cartilage degeneration following strut grafting and trapdoor procedures for osteonecrosis of the femoral head in an ovine model. Osteonecrosis and a bony defect were created surgically in 16 hips of 8 Merino sheep, and the index grafting procedures were performed in a second session. Three months after surgery, the hips treated by strut grafting yielded better articular cartilage protection and bony healing compared to the osteonecrosis groups. The trapdoor group yielded better bony healing compared to the rest of the groups, but the grafts and the osteochondral flaps failed to unite with the host bone. These findings indicate elevating the osteochondral flap during the trapdoor procedure injures the cartilage and may cause degeneration.

GDF9 and BMP15 Expressions and Fine Structure Changes during Folliculogenesis in Polycystic Ovary Syndrome.

Background: Polycystic ovary syndrome is the most frequently seen endocrine disorder in women of reproductive age with a prevalence of about 10%. Aims: To investigate the efficiency of growth differentiation factor 9 and bone morphogenetic protein 15 during folliculogenesis in a dehydroepiandrosterone-induced mouse Polycystic ovary syndrome model. Study Design: Animal experimentation. Methods: Mice were divided into 3 groups: control, vehicle and Polycystic ovary syndrome. Polycystic ovary syndrome model mice were developed by the injection of dehydroepiandrosterone dissolved in 0.1 mL of sesame oil. Ovarian tissues were examined for growth differentiation factor 9 and bone morphogenetic protein 15 using immunofluorescent labelling and electron microscopic examinations. Results: The immunoreactivity of growth differentiation factor 9 and bone morphogenetic protein 15 proteins decreased (p<0.05) in the Polycystic ovary syndrome group (27.73±8.43 and 24.85±7.03, respectively) compared with the control group (33.72±11.22 and 31.12±11.05, respectively) and vehicle group (33.95±10.75 and 29.99±10.72, respectively). Apoptotic changes were observed in granulosa cells, lipid vacuoles increased in Theca cells and thickening and irregularities were noted in the basal lamina of granulosa cells. An increased electron density in the zona pellucida in some of the multilaminar primary and secondary follicles in the Polycystic ovary syndrome model was also observed at the ultrastructural level. Conclusion: These results suggest that the decrease in the growth differentiation factor 9 and bone morphogenetic protein 15 expression initiated at the primary follicle stage effect the follicle development and zona pellucida structure and may cause subfertility or infertility in Polycystic ovary syndrome.