Effects of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells on microRNA Expressions in Acute Alkaline Corneal Burn.

Purpose: The aim of this study was to investigate the microRNA (miRNA) expressions of the corneal tissue after an alkaline burn and to compare the efficiency of adipose- and bone marrow-derived mesenchymal stem cells (MSCs) on expressions. Methods: Thirty-two rats were divided into 4 groups. No intervention was made in the control group. A chemical burn was created by applying 4 µL NaOH soaked in 6 mm filter paper to the right eye of each animal in the other groups. Whereas only subconjunctival 0.1 mL phosphate-buffered saline (PBS) was injected to in the group 1, 2 × 106 adipose- or bone marrow-derived MSC in 0.1 mL PBS was injected subconjunctivally to the animals in the remaining groups (groups 2 and 3, respectively). Tissue samples were collected for miRNA analysis on the third day after the burn. Results: When group 1 was compared with the control group, the expression of 3 of 93 miRNAs increased significantly, whereas the expression of 50 miRNAs decreased significantly. Significant changes in miRNA expressions were observed when group 1 was compared with groups 2 and 3. Although a significant change was observed in the expression of 6 miRNAs in the adipose-derived MSC group, it was found that the expression of 65 miRNAs significantly changed in the bone marrow-derived MSC group. Conclusion: This study shows that there are significant changes in some miRNA expressions after corneal alkaline burn and these changes can be reversed with the subconjunctival injection of MSCs.

Retinal endoilluminator toxicity of xenon and light-emitting diode (LED) light source: rabbit model.

OBJECTIVE: This study evaluates retinal toxicity due to endoillumination with the light-emitting diode (LED) light source in comparison to endoillumination with xenon light source. MATERIAL AND METHODS: Twenty-five eyes of 14 New Zealand pigmented rabbits were used in the study. The LED light (Omesis Medical Systems, Turkey) group was composed of 7 right eyes, while the other 7 right eyes constituted the xenon group (420 nm filter, 357mW/cm(2)) (Bright Star; DORC, Zuidland, Netherlands). Eleven untreated left eyes composed the control group. Twenty gauge pars plana incision 1.5 mm behind the limbus was performed in the right eyes. Twenty gauge bullet type fiberoptic endoilluminator was inserted into the eye from the incision without any pars plana vitrectomy. Fiberoptic endoilluminator was placed in such a way that it was directed toward visual streak of the rabbit retina with a 5 mm distance to retinal surface. Endoillumination was then applied for 20 min with a maximum light intensity for LED and xenon light. In left control eyes, no surgical procedure and no endoillumination were performed. One week after the endoillumination procedure, both eyes of the rabbits were enucleated following electroretinography. Sections stained with hematoxylin and eosin to evaluate morphologic changes. Retina tissues were assessed by active caspase-3 staining. RESULTS: There was no difference in the shape of the waveforms recorded in the eyes endoilluminated with LED light and xenon light sources compared to control eyes both before and after endoillumination application (p > 0.05). Microscopic evaluation of the retinas with hematoxylin and eosin staining demonstrated that all study groups have normal histologic properties similar to control group. No apoptosis positive cells were found within all sections in all groups. CONCLUSIONS: When the LED light source is used with maximum power and limited duration for endoillumination in rabbit eyes it does not produce phototoxic effects that may be detectable by electrophysiology and histology similar to xenon light.

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

UNLABELLED: 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 (60)Co 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.

Deterioration of bone quality by long-term magnetic field with extremely low frequency in rats.

The aim of our study was to investigate the effects of long-term (45 days) magnetic field (50 Hz, 1 mT; MF) on femur biomechanical parameters of rats. Bone mineral density (BMD) and histological investigation were also evaluated. For this purpose, twenty-four 8-week-old, Wistar-Albino female and male rats were assigned randomly to female control (FC) and MF-exposed rats (F-MF); male control (MC) and MF-exposed rats (M-MF). BMD was measured by dual-energy X-ray absorptiometry. Cross-sectional area of the femoral shaft was evaluated by computerized tomography. Biomechanical measurements were performed at the mid-diaphysis of the left femur with tensile test. Maximum load, displacement, stiffness, energy absorption capacity (structural properties); ultimate stress, ultimate strain, elastic modulus and toughness (material properties) were calculated. Diaphysial cortical bone thickness was measured by using histological method from the right femur. In respect to the cortical thickness of the rats' femurs, there was statistically significant interaction between the gender and group (P<0.05), while the BMD and cortical area were not (P>0.05). The BMD, cortical thickness and area values of the femurs of MF-exposed rats (F-MF, M-MF) were significantly decreased in comparison to that of the controls (FC, MC) (P<0.05). There were no statistically significant differences between the control and the MF-exposed rats in respect to the femur length (P>0.05). There were no statistically significant interaction between the gender and group with regard to the maximum load, displacement, stiffness, ultimate stress, ultimate strain, elastic modulus and toughness endpoints, while the energy absorption capacity was significant (P<0.05). Maximum load, displacement and stiffness values of MF-exposed rats were significantly decreased compared to that of the controls (P<0.05). Femurs of M-MF rats had less absorbed energy than that in controls (P<0.05). Ultimate stress and elastic modulus parameters were significantly decreased in MF-exposed rats in comparison to that of the controls (P<0.05). Ultimate strain was higher in MF-exposed rats than that in controls (P>0.05). The mean of toughness was decreased in MF-exposed rats compared to that of the controls (P>0.05). In conclusion, the bone quality of rats is decreased by magnetic field exposure.