Monitoring the osseointegration process in porous Ti6Al4V implants produced by additive manufacturing: an experimental study in sheep.

BACKGROUND: This study investigated the design and osseointegration process of transitive porous implants that can be used in humans and all trabecular and compact bone structure animals. The aim was to find a way of forming a strong and durable tissue bond on the bone-implant interface. METHODS: Massive and transitive porous implants were produced on a direct metal laser sintering machine, surgically implanted into the skulls of sheep and kept in place for 12 weeks. At the end of the 12-week period, the Massive and porous implants removed from the sheep were investigated by scanning electron microscopy (SEM) to monitor the osseointegration process. RESULTS: In the literature, each study has selected standard sizes for pore diameter in the structures they use. However, none of these involved transitional porous structures. In this study, as opposed to standard pores, there were spherical or elliptical pores at the micro level, development channels and an inner region. Bone cells developed in the inner region. Transitive pores grown gradually in accordance with the natural structure of the bone were modeled in the inner region for cells to develop. Due to this structure, a strong and durable tissue bond could be formed at the bone-implant interface. CONCLUSIONS: Osseointegration processes of Massive vs. porous implants were compared. It was observed that cells were concentrated on the surface of Massive implants. Therefore, osseointegration between implant and bone was less than that of porous implants. In transitive porous implants, as opposed to Massive implants, an outer region was formed in the bone-implant interface that allowed tissue development.

Resveratrol Treatment Prevents Hippocampal Neurodegeneration in a Rodent Model of Traumatic Brain Injury.

AIM: Traumatic brain injury (TBI) is a complex process. Increasing evidence has demonstrated that reactive oxygen species contribute to brain injury. Resveratrol (RVT) which exhibits significant antioxidant properties, is neuroprotective against excitotoxicity, ischemia, and hypoxia. The aim of this study was to evaluate the neuroprotective effects of RVT on the hippocampus of a rat model of TBI. MATERIAL AND METHODS: Twenty eight rats were divided into four groups. A moderate degree of head trauma was induced using Feeney"s falling weight technique. Group 1 (control) underwent no intervention or treatment. Head trauma was induced in Group 2 (trauma) and no drug was administered. Head trauma was induced in Group 3 and low-dose RVT (50 mg/kg per day) was injected. In Group 4, high-dose RVT (100 mg/kg per day) was used after head trauma. Brain tissues were extracted immediately after perfusion without damaging the tissues. Histopathological and biochemistry parameters were studied. RESULTS: Brain tissue malondialdehyde (MDA) levels in the trauma group were significantly higher than those in the control, lowdose RVT-treated, and high-dose-RVT-treated groups. The superoxide dismutase (SOD) levels in the control group were significantly higher than those in the trauma, low-dose RVT-treated, and high-dose RVT-treated groups. Glutathione peroxidase (GSH-Px) levels in the control group were significantly higher than those in the trauma and low-dose RVT-treated groups. The level of oxidative deoxyribonucleic acid (DNA) damage (8-OHdG/106 dG) in the trauma group was higher than that in the control group, low-dose RVT-treated, and high-dose RVT-treated groups. CONCLUSION: Resveratrol has a healing effect on neurons after TBI.

Effects of Low-Intensity Treadmill Exercise on Sciatic Nerve in Experimental Diabetic Neuropathy.

OBJECTIVE: To investigate the potential beneficial effects of low-intensity exercise on histopathological changes of sciatic nerves in streptozotocin (STZ)-induced diabetic rats. STUDY DESIGN: The rats were allotted randomly into 3 experimental groups: A (control), B (diabetic untreated), and C (diabetic treated with low-intensity exercise); each group contained 8 animals. Groups B and C received STZ. Diabetes was induced in 2 groups by a single intraperitoneal injection of STZ (40 mg/kg, freshly dissolved in 0.1 M citrate buffer, pH 4.2). Two days after STZ treatment, diabetes in 2 experimental groups was confirmed by measuring blood glucose levels. Rats with blood glucose levels ≥ 250 mg/dL were considered to be diabetic. Animals in the exercise group were made to run the treadmill once a day for 4 consecutive weeks. Exercise started 3 days prior to STZ administration. RESULTS: The treatment of low-intensity exercise caused a sharp decrease in the elevated serum glucose and an increase in the lowered serum insulin concentrations in STZ-induced diabetic rats. STZ induced a significant decrease in the area of insulin-immunoreactive ß cells. Low-intensity exercise treatment resulted in increased area of insulin-immunoreactive ß cells signficantly. Myelin breakdown decreased significantly after treatment with low intensity exercise. The ultrastructural features of degenerated axons also showed remarkable improvement. CONCLUSION: We believe that further preclinical research into low-intensity exercise may indicate its usefulness as a potential treatment for peripheral neuropathy in STZ-induced diabetic rats.

The effects of caffeic acid phenethyl ester on inflammatory cytokines after acute spinal cord injury.

BACKGROUND: The purpose of this study was to investigate the effects of Caffeic Acid Phenethyl Ester (CAPE) on proinflammatory cytokines, IL-1ß and TNF-α, and explore its healing effect after acute spinal cord injury. METHODS: Forty-eight male Wistar-Albino rats were used in this study which was planned as three groups. All groups were divided into two sub-groups. Group 1a was the control group, in which only lower segment thoracic laminectomy was performed. In group 1b, spinal cord trauma was performed with aneurysm clip. In the second group, serum physiologic was given systemically thirty minutes after trauma, and rats were sacrificed after the first and sixth hour. In the third group, CAPE was given systemically thirty minutes after trauma, and rats were sacrificed after the first and sixth hour. Serum IL-1ß and TNF-α levels were analyzed by ELISA in the serum. Histopathological analysis was performed in damaged cord tissues. RESULTS: CAPE suppressed TNF-α and IL-1ß levels in the serum. In histopathological evaluation, it was detected that CAPE decreased hemorrhage and necrosis. CONCLUSION: CAPE suppresses the levels of proinflammatory cytokines, TNF-α and IL-1ß, after acute spinal cord injury in the early phase and contributes to the healing process.