Effects of diabetes on apoptosis and mitosis in rat hippocampus.

Diabetes contributes to neurological dysfunction including peripheral nerve diseases, stroke and dementia. We investigated the effects of diabetes on apoptosis and mitosis in the hippocampal CA1 region. Rats were given diabetes by injection of streptozotocin (STZ). The mass and blood glucose levels of the rats were measured until day 7 of the experiment. The loss of mass index was approximately 10%, and the diabetogenic index was approximately 330% between nondiabetic and diabetic groups. We investigated caspase-3, caspase-7 and Ki 67 levels immunohistochemically for mitotic activity, the TUNEL method for apoptosis and GFAP for astrocyte cell density in the hippocampal CA1 region. We found that apoptotic cells and the number of astrocytes and mitotic activity in the diabetic group were increased significantly compared to controls. Diabetes stimulates apoptosis and promotes cell proliferation in the hippocampal CA1 region, which may impair its homeostasis and function.

A digital image analysis study on the disintegration kinetics of reticular fibers in the ethylene glycol-induced rat liver tissue.

Ethylene glycol (EG), the raw material of polyethylenterephthalate, which is the most consumed plastic in the world, has low toxicity, but its metabolites are toxic. EG metabolites can cause acidosis, fibrosis, and eventually cirrhosis in the liver. This study aimed to investigate the effect of EG on rat liver and to determine the quantitative values of the disintegration of reticular fibers (RF) in the liver with the dose duration and to investigate the changes by digital image analysis (DIA). For this purpose, Wistar albino rats were divided into control, and five different daily experimental groups. The control group received saline, and the experimental groups received EG. At the end of experiments, liver tissues of all euthanized rats were removed, and sections were taken, and RF was shown by silver staining. It was observed that the RF fragments in the experimental groups were less than the control group. DIA of RF fragments was then performed with Olympus cellSensDimension 1.15 software and number, area, and ROI% values of the fragments were determined. Statistical analysis revealed that there was a significant difference between control and all experimental groups. RF fragments showed first-order disintegration kinetics, mean disintegration rate constant, and half-time values were 0.1 day-1 and 7 days, respectively. Consequently, the digital image analysis approach can be a useful tool for the biologist, pathologist, fibrosis-cirrhosis specialist, and computer scientist to understand the effects of toxic chemicals in the liver and analyze reticular fiber disintegration.

A study of digital image analysis on the acrylamide derivative monomers induced apoptosis in rat cerebrum.

Nowadays, apoptosis is mostly evaluated visually in histological studies. By using the quantitative digital image analysis, this study aimed to investigate the effect of acrylamide-based monomers (acrylamide [AAm], methacrylamide [MAAm], N-isopropylacrylamide [NIPAm]) on the cerebrum tissues in rats, which are the most common water-soluble monomers in the production of polymeric hydrogels used as biomaterials. The Wistar albino rats weighing ~220-240 g were divided into control and three test groups. The control group received 1 mL of saline, and the test groups received 1 mL of aqueous 50 mg/kg/day intramuscular injection of AAm, MAAm, and NIPAm, respectively. At the end of the experiments, brain tissues of all rats euthanized by intramuscular injection of sodium pentobarbital were removed. Terminal deoxynucleotide transferase dUTP nick and labeling (TUNEL) method was applied to brain tissue sections. The monomers have been shown to cause apoptosis due to oxidative stress in cerebrum tissue. Based on apoptosis by tunneling method, quantitative digital image analysis of cell fragments was performed with Olympus cellSens Dimension 1.15 software, and the number, total count area, selected area, average area, and ROI% values of the fragments were found. In addition, the total area and ROI% values of the fragments increased linearly with increasing the molar mass of monomers from the digital image analysis data. Quantitative digital image analysis can facilitate the monitoring of apoptosis caused by the oxidative stress of monomers used in the production of the biomaterials.

Effect of Strontium Ranelate on Condylar Growth during Mandibular Advancement in Rats.

OBJECTIVE: Strontium ranelate (SR), unlike other anti-osteoporotic agents, might not only prevent bone resorption but also might induce bone formation. The aim of this experimental study was to evaluate the effects of systemic SR on condylar growth during mandibular advancement (MA) in growing rats. METHODS: Fifty-six, 8-week-old Wistar male rats weighting 160-190 g were randomly divided into four groups; one control (n=14) and three experimental (n=14). Group 1: Control group, Group 2: SR (900mg/kg daily dose), Group 3: MA, Group 4: SR +MA. The amount and direction of mandibular growth were assessed by linear measurements on the computed tomography (CT) images taken on days 1, 15, and 30. For immunohistochemical evaluation, half of the subjects in the groups were sacrificed on the 15th day (early phase) and the rest of them on the 30th day (late phase). New cartilage and bone formation areas on the condyle were analyzed by using Sox9 and Osteopontin antibodies. RESULTS: Early and late CT images measurements showed no significant difference between the groups (p<0.05). However, there were significant differences between the control and experimental groups in the immunohistochemical assessment. Severe immunolocalization of SOX9 and Osteopontin was observed in Group 4, while the immunolocalization scores were moderate in Group 2 and Group 3. In addition, early histological findings were similar to late results in all groups. CONCLUSION: In mandibular advancement therapy, Strontium ranelate could be therapeutically effective in avoiding relapse and reducing the duration of retention.

The bone-healing effect of a xenograft in a rat calvarial defect model.

Bone grafts have been widely used to fill osseous defects in medicine, dentistry, and periodontology. The purpose of this study was to investigate the effects of a xenograft (Unilab Surgibone) on experimentally created parietal bone defects in rats. To this end, 14 rats were employed in the present study and in each of them, 5-mm-diameter defects were created on the parietal bone. The right defect sites were filled with the xenograft material, while the left sites were used as control. After 30 days, the rats were sacrificed and tissue samples were retrieved from the defect sites of the cranium. Dense collagenous tissue was observed in the control area, whereas the xenograft particles were surrounded by a fibrous tissue layer at the implantation site. Based on the findings obtained, it could be concluded that the investigated xenograft seemed biocompatible and could be proposed as a potential material for filling osseous defects.