The osteoinductive potential of different root-end filling materials in a rat femur model

In pediatric dentistry, the enduring success of root-end filling materials employed for the establishment of apical plugs in immature teeth undergoing endodontic intervention is contingent upon their possessing a robust osteoinductive capacity. Hence, the primary objective of this study was to histologically assess the osteoinductive potential of four distinct dental materials, specifically recommended for retrograde filling applications, utilizing an animal hard tissue model. Within the designed experimental model, two bone defects measuring 2 mm in diameter and 2 mm in depth were created in both femurs of a cohort comprising 21 male Wistar albino rats. The first defect in the right femur was left blank as the control group, and Neo MTA Plus was placed in the second defect. The EndoSequence BCRRM Fast Set Putty was placed in the first of the defects on the left femur, and Endo Repair was placed in the second defect. Subjects were sacrificed after 7, 14, and 28 days of follow-up, and sections were examined to assess the degree of inflammation, connective tissue formation, and new bone formation. The data were statistically evaluated with Kruskal‒Wallis and post hoc Dunn's tests using SPSS 12 software. The bone healing levels of the Neo MTA Plus group were significantly higher than those of the other groups in all periods (p < 0.05). Bone organization in all groups decreased over time, and fibrous tissue was enriched. The results of this study demonstrate that NeoMta Plus has superior osteoinductive properties compared to other materials but that EndoSequence and Endo Repair have the potential to be developed.

Cytotoxic effect of silica nanoparticles on human retinal pigment epithelial cells.

In recent years, the use of nanotechnology-based methods has become widespread in the treatment of ocular diseases. Silica nanoparticles (SiO2 NPs) are most common used NPs in medical field due to their physicochemical properties. SiO2 NPs can easily cross biological membranes and interact with basic biological structures, causing structural and functional changes in cells. In this study, it was aimed to investigate the dose dependent effect of SiO2 NPs on retinal pigment epithelium (RPE) in vitro using electrobiophysical, biochemical and histological methods. A commercially purchased human RPE (hARPE-19) cell line was used in this study. Cells were divided into four groups as control, 50 µg/mL SiO2, 100 µg/mL SiO2 and 150 µg/mL SiO2 groups. Cell index, apoptotic activity, cell cycle and oxidative stress markers were measured in all groups. Findings in the present study showed that SiO2 nanoparticles reduced cell proliferation, increased oxidative stress, apoptosis and arrest in the G0/G1 phase of the cell cycle as dose dependent manner in ARPE-19 cells. In conclusion, SiO2 exposure can induce cytotoxic effects in RPE cell line. The results of this study provide clues that exposure to SiO2 nanoparticles may impair visual function and reduce quality of life. However, further studies are needed in this regard.

Non-Destructive Removal of Dental Implant by Using the Cryogenic Method.

Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in cases where the implant needs to be removed. Removing the implant with minimal damage to the surrounding tissues is important. Osteocytes cannot survive below −2 °C, but epithelial cells, fibroblasts, and other surrounding tissue cells can. Remodeling can be triggered by cryotherapy at temperatures that specifically affect osteocyte necrosis. In this study, we aimed to develop a method for reversing the osseointegration mechanism and for protecting the surrounding tissues by bone remodeling induced by CO2 cryotherapy. Materials and Methods: In this study, eight 2.8 mm diameter, one-piece mini implants were used in New Zealand rabbit tibias. Two control and six implants were tested in this study. After 2 months of osseointegration, a reverse torque force method was used to remove all osseointegrated implants at 5, 10, 20, and 30 Ncm. The osseointegration of the implants was proven by periotest measurements. Changes in bone tissue were examined in histological sections stained with toluidine blue after rabbit sacrifice. The number of lacunae with osteocyte, empty lacunae, and lacunae greater than 5 µm and the osteon number in a 10,000 µm2 area were calculated. Cryotherapy was applied to the test implants for 1 min, 2 min, and 5 min. Three implants were subjected to cryotherapy at −40 °C, and the other implants were subjected to cryotherapy at −80 °C. Results: Empty lacunae, filled osteocytes, lacunae >5 µm, and the osteon count around the implant applied at −40 °C were not significantly different from the control implants. The application of −40 °C for 1 min was found to cause minimal damage to the bone cells. The implants, which were applied for 1 min and 2 min, were successfully explanted on the 2nd day with the 5 Ncm reverse torque method. Test implants, which were applied cold for 5 min, were explanted on day 1. Tissue damage was detected in all test groups at −80 °C. Conclusions: The method of removing implants with cryotherapy was found to be successful in −40 °C freeze−thaw cycles applied three times for 1 min. To prove implant removal with cryotherapy, more implant trials should be conducted.

Impact of injectable chitosan cryogel microspherescaffolds on differentiation and proliferation of adiposederived mesenchymal stem cells into fat cells.

Difficulty in the clinical practice of stem cell therapy is often experienced in achieving desired target tissue cell differentiation and migration of stem cells to other tissue compartments where they are destroyed or die. This study was performed to evaluate if mesenchymal stem cells (MSCs) may differentiate into desired cell types when injected after combined with an injectable cryogel scaffold and to investigate if this scaffold may help in preventing cells from passing into different tissue compartments. MSCs were obtained from fat tissue of the rabbits as autografts and nuclei and cytoplasms of these cells were labeled with BrdU and PKH26. In Group 1, only-scaffold; in Group 2, only-MSCs; and in Group 3, combined stem cell/scaffold were injected to the right malar area of the rabbits. At postoperative 3 weeks, volumes of the injected areas were calculated by computer-tomography scans and histopathological evaluation was performed. The increase in the volume of the right malar areas was more in Group 3. In histopathological evaluation, chitosan cryogel microspheres were observed microscopically within the tissue and the scaffold was only partially degraded. Normal tissue form was seen in Group 2. Cells differentiated morphologically into fat cells were detected in Groups 2 and 3. Injectable chitosan cryogel microspheres were used in vivo for the first time in this study. As it was demonstrated to be useful in carrying MSCs to the reconstructed area, help cell differentiation to desired cells and prevent migration to other tissue compartments, it may be used for reconstructive purposes in the future.

Involvement of Rho-kinase/IκB-α/NF-κB activation in IL-1ß-induced inflammatory response and oxidative stress in human chondrocytes.

It has been clearly indicated that osteoarthritis (OA) is an inflammatory and degenerative disease that could be promoted by Rho-kinase (ROCK); however, little is known about the role of ROCK/inhibitor κB alpha (IκB-α)/nuclear factor-κB (NF-κB) p65 pathway activation in interleukin-1ß (IL-1ß) induced inflammatory response and oxidative stress in primary human chondrocytes. To test this hypothesis, we focused on determining ROCK-II, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), p22phox, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subtype 4 (NOX4) protein expression, ROCK-II activity, NADPH oxidase levels, and total antioxidant capacity (TAC) in the presence and absence of ROCK-inhibitor fasudil. IL-1ß (2 ng·mL-1, 24 h) increased the expression of ROCK-II, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, TNF-α, COX-2, and p22phox proteins, and decreased the expression of IκB-α, and the NOX4 protein level did not alter. ROCK activity and NADPH oxidase levels were increased, whereas the TAC was decreased by IL-1ß. Fasudil (10-5-10-7 M) reversed all these changes induced by IL-1ß. These results demonstrate that ROCK/IκB-α/NF-κB p65 pathway activation contributes to the IL-1ß-induced inflammatory response and oxidative stress, and thus, ROCK inhibition might be a beneficial treatment option for OA patients mainly based on its anti-inflammatory and antioxidant effects.

mTOR inhibition as a possible pharmacological target in the management of systemic inflammatory response and associated neuroinflammation by lipopolysaccharide challenge in rats.

Neuroinflammation plays a critical role during sepsis triggered by microglial activation. Mammalian target of rapamycin (mTOR) has gained attraction in neuroinflammation, however, the mechanism remains unclear. Our goal was to assess the effects of mTOR inhibition by rapamycin on inflammation, microglial activation, oxidative stress, and apoptosis associated with the changes in the inhibitor-κB (IκB)-α/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α) pathway activity following a systemic challenge with lipopolysaccharide (LPS). Rats received saline (10 mL/kg), LPS (10 mg/kg), and (or) rapamycin (1 mg/kg) intraperitoneally. Inhibition of mTOR by rapamycin blocked phosphorylated form of ribosomal protein S6, NF-κB p65 activity by increasing degradation of IκB-α in parallel with HIF-1α expression increased by LPS in the kidney, heart, lung, and brain tissues. Rapamycin attenuated the increment in the expression of tumor necrosis factor-α and interleukin-1ß, the inducible nitric oxide synthase, gp91phox, and p47phox in addition to nitrite levels elicited by LPS in tissues or sera. Concomitantly, rapamycin treatment reduced microglial activation, brain expression of caspase-3, and Bcl-2-associated X protein while it increased expression of B cell lymphoma 2 induced by LPS. Overall, this study supports the hypothesis that mTOR contributes to the detrimental effect of LPS-induced systemic inflammatory response associated with neuroinflammation via IκB-α/NF-κB/HIF-1α signaling pathway.

Comparison of the Effects of Pulsed Electromagnetic Field and Extracorporeal Shockwave Therapy in a Rabbit Model of Experimentally Induced Achilles Tendon Injury.

Achilles tendon injuries are a common cause of complications including adhesions and tendon degeneration. As a result of these complications, the biomechanical properties are lost. Extracorporeal shockwave therapy (ESWT) and pulsed electromagnetic field (PEMF) recover the injured tendon structure; however, detailed studies of changes in tendon biomechanical properties are limited. We hypothesized that PEMF application would improve Achilles tendon biomechanical properties similar to ESWT. The curative effects of a PEMF 4-week application (15 Hz, 1 mT, 260 µs, 1 h/day) and ESWT (3 doses/28 days, 1st dose: 0.12 mJ/mm2 , 15 Hz, 300 impulses; 2nd dose: 0.14 mJ/mm2 , 15 Hz, 500 impulses; 3rd dose: 0.14 mJ/mm2 , 15 Hz, 500 impulses) on rabbits with Achilles tendon injury were investigated in terms of histopathological and biomechanical properties. The clinical feasibility of PEMF application was evaluated by comparing the results of both methods. Fifty New Zealand female rabbits were divided into two groups to be used in either biomechanical or immunohistochemical studies. Each of the two groups was further divided into five groups: C (Control), SH (Sham), TI (tendon injury), TI + ESWT, and TI + PEMF. Biomechanical evaluations revealed that maximum load, toughness, and maximum stress averages of the TI + PEMF group significantly increased (P < 0.05). When immunohistochemical images of the TI + PEMF group were compared with those of the TI group, the amount of fibrous tissue was less, the homogeneity of collagen fibers recovered, and collagen organization was more uniform. We conclude that both ESWT and PEMF are equally efficient for Achilles tendon recovery. PEMF application is effective and can be used in the clinic as a painless alternative treatment method. © 2020 Bioelectromagnetics Society.

Evaluation of Anti-Inflammatory and Antiapoptotic Effects of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells in Acute Alkaline Corneal Burn.

Purpose: The aim of the present study is to comparatively evaluate the anti-inflammatory and antiapoptotic effects of bone marrow and adipose-derived mesenchymal stem cells (MSCs) applied subconjunctivally after alkaline corneal burn. Methods: Thirty-two rats were divided into 4 groups and included in the study (n = 8). While no intervention was made in the control group, a chemical burn was created by applying 4 µL of NaOH soaked in 6 mm filter paper to the right eye of each subject in the other groups under general anesthesia. While 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 applied subconjunctivally to the subjects in the remaining groups (Group 2 and 3, respectively). Tissue samples were collected for histological analysis on the third day after the burn. Tissue samples were evaluated light microscopically and immunohistochemically stained for interleukin-1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), caspase-3 (Cas-3), and CD68. Results: The IL-1ß and TNF-α staining scores and the number of CD68- and Cas-3-positive stained cells were significantly lower in the groups given bone marrow and adipose-derived MSC compared to the alkaline burn group (P < 0.0001, for all parameters). Epithelial IL-1ß and TNF-α staining scores were significantly lower in the bone marrow-derived MSC group compared to the adipose-derived MSC group (P < 0.0001, for all parameters). Conclusions: The presented study shows that both bone-marrow and adipose-derived MSCs support wound healing in the corneal tissue and strongly suppress the inflammation occured in the tissue.

Perifosine and vitamin D combination induces apoptotic and non-apoptotic cell death in endometrial cancer cells.

Endometrial cancer is the most common cancer of the female reproductive system. Combination treatment with specific agents has been widely used as a targeted therapy for cancer. In this study, we aimed to investigate the anti-proliferative and apoptotic effects of varying concentrations of perifosine and vitamin D on the human endometrial cancer cell line (HEC-1A). HEC-1A cells were exposed to perifosine (10 µM, 30 µM), vitamin D (50 nM, 200 nM) and combinations of both for 48 h and 72 h. Monitoring of cell proliferation in a time-dependent manner was performed with the xCELLigence RTCA DP system. The levels of BCL2, BAX and P53 mRNA expression were examined using RT-qPCR. Apoptosis was determined using Annexin V, which were followed by flow cytometry analysis. Ultra-structural morphology of cells was analyzed by transmission electron microscopy (TEM) for 72 h. The anti-proliferative and apoptotic effects of the perifosine+vitamin D combination (30 µM + 200 nM at 48 h and 10 µM + 200 nM at 72 h) on HEC-1A cells were higher than in perifosine and vitamin D alone. It was observed that perifosine has increased the expression of BAX mRNA in HEC-1A cells in a dose-dependent manner. While perifosine+vitamin D combinations increased P53 mRNA expression in HEC-1A cells we did not find any significant change in BCL2, BAX mRNA expression levels. In TEM examinations of HEC-1A cells, perifosine appeared to lead autophagic cell death, whereas vitamin D caused paraptosis-like cell death and combination of perifosine+vitamin D caused apoptotic and non-apoptotic (paraptotic, autophagic and necrotic) cell death. Therefore, it is considered that the combination of both drugs in the treatment of endometrial cancer might be an alternative and effective treatment option through activating the apoptotic and non-apoptotic cell death mechanisms in cancer cells.

Effects of different cadaver preservation methods on muscles and tendons: a morphometric, biomechanical and histological study.

No prior publication studying the biomechanical and histological properties of cadavers fixed with Logan or modified Logan solution (MLS) was found in the literature. It was aimed in this study to compare MLS fixation and other cadaver preservation procedures regarding the use in basic histological studies, anatomy education and surgical trainings. This study was placed on 35 male 17-week-old Wistar Albino rats. MLS fixated tissues were systematically compared with 10% formalin (F10), saturated salt solution (SSS), Thiel and frozen/thawed (FT) tissues. Organoleptic (color, appearance, flexibility, odor, etc.), morphometric (e.g. length, width and cross-sectional area), biomechanical (Young's modulus, stiffness, maximum load, etc.) and histological (tendon and muscle fiber integrity, nuclear prominence, blur in microscopy, etc.) analyses were conducted. Organoleptic properties of Thiel and SSS fixated muscles and tendons were better preserved than F10 and MLS. No significant difference was observed in gross morphometric properties (e.g. length, width and cross sectional area) following any of the cadaver and tissue preservation techniques. MLS and F10 was observed to increase the stiffness, Young's modulus and maximum load parameters of the tendons. Thiel and SSS fixated tendons had similar mechanical properties to fresh and FT tendons. No effect of fixation solutions on tendons is observed in the histological analysis regarding fiber integrity, nuclear prominence, blur in microscopy, shrinkage of tissues. Thiel solution was observed to distort fiber integrity, nuclear prominence and blur the microscopy of muscle tissue. Thiel and SSS fixated muscles and tendons were observed to absorb more stain with Masson's trichrome staining and appear as darker red. No muscle and tendon shrinkage due to fixative solutions was observed with our fixation method. Pondering the organoleptic (color, appearance, consistency, odor, etc.) and biomechanical analyses (stiffness, Young's modulus, etc.), Thiel and SSS fixed cadavers are more suitable for purposes as surgical trainings and development of new surgical procedures. However, the change in the micro-anatomical structure of the muscles, especially with the Masson's trichrome staining, caused by these two solutions should not be overlooked.

Effect of Imipramine on radiosensitivity of Prostate Cancer: An In Vitro Study.

Prostate cancer is the most common cancer and leading cause of cancer death for males. Imipramine (IMI), which is a tricyclic antidepressant, has also been shown to has antineoplastic effect. This study was performed to investigate the radiosensitizing effect of IMI on DU145 prostate cancer cell. Cells were divided into 4 groups. Cell index, apoptotic activity, cell cycle arrest, oxidative stress and EAG1 channel currents were determined in all groups. Our findings showed that combined treatment with IMI and radiotherapy (RAD) did not enhance radiosensitivity of DU145 cells but as unexpected finding, treatment of IMI alone was more effective in DU145 cells.

Evaluation of the stapedial tendon growth dynamic in human fetuses.

PURPOSE: The main objective of the study was to investigate the morphometric properties of the stapedial tendon (ST) for pediatric otosurgeons and anatomists. METHODS: The present study was placed on 15 fetuses (8 females, 7 males) aged from 20 to 30 weeks of gestation (at mean, 24.27 ± 3.24 weeks) using the collection of the Anatomy Department of Medicine Faculty, Mersin University. All measurements were obtained with a digital image analysis software. RESULTS: In terms of male/female or right/left comparisons, no statistically significant difference was found in relation with the numerical data of ST. The surface area, length, and width of ST were detected as follows: 0.61 ± 0.15 mm2, 1.27 ± 0.30 mm, and 0.45 ± 0.08 mm, respectively. The absence of ST was observed in two fetuses with and without severe malformations. In another fetus with cleft lip and polydactyly, multiple abnormalities were bilaterally identified in the middle ear: (1) the absence of the incudostapedial joint and (2) the presence of an abnormal tissue attaching to the stapes. The abnormal tissue was determined to be irregular dense connective tissue using light microscope and electron microscope. CONCLUSION: Our findings showed that ST did not proportionally grow according to increasing gestational weeks. In the light of the numerical data, we thought that similar to stapes, ST attains the adult size in the fetal period. As ST anomalies may accompany severe malformations (e.g., cleft lip, polydactyly or syndactyly) that can be easily detected on observation by clinicians, we suggest that the detailed examination of middle ear in newborns should be taken into account for early diagnosis of conductive hearing loss to prevent any management delays.

Toxic effect of acetamiprid on Rana ridibunda sciatic nerve (electrophysiological and histopathological potential).

In this study, the effects of a neonicotinoid insecticide acetamiprid on the sciatic nerve of Rana ridibunda were investigated by using electrophysiological and histological methods. A total of 35 preparations of sciatic nerve isolated from 35 frogs (Nervus ischiadicus) were used in the experiments. Experiments were designed as four different dose groups (n = 8 per group). Acetamiprid solutions of 1 (group 1), 10 (group 2), 100 (group 3), and 1000 µM (group 4) were applied to the nerves in dose groups. In each group, action potentials were recorded before application of acetamiprid which served as control data. The extracellular action potentials were recorded for each group of 30th, 60th, 90th and 120th min of application time. Action potential amplitude and area were measured from recordings. Histological evaluation was performed by transmission electron microscopy. In electrophysiological examination, all doses in which acetamiprid applied have shown the effect from the 30th min and suppressed the sciatic nerve action potential. Acetamiprid significantly reduced the amplitude at the rate of 78-96% and the area at the rate of 79-98% (p < 0.05). In electron microscopic examination, the control nerves were in normal appearance. Disorganization, irregularity, dense ovoid body formation, fragmentation of the myelin sheath, and loss on some axoplasm of the nerves in the dose group have been observed. Our findings showed that acetamiprid can cause neuropathic changes in sciatic nerve at all applied doses. These results indicate that acetamiprid as other insecticides can have harmful effects on non-target organisms.

N-Acetylcysteine-induced vasodilatation is modulated by KATP channels, Na+/K+-ATPase activity and intracellular calcium concentration: An in vitro study.

BACKGROUND: In this study, we aimed to investigate the role of ATP-sensitive potassium (KATP) channel, Na+/K+-ATPase activity, and intracellular calcium levels on the vasodilatory effect of N-acetylcysteine (NAC) in thoracic aorta by using electrophysiological and molecular techniques. METHODS: Rat thoracic aorta ring preparations and cultured thoracic aorta cells were divided into four groups as control, 2mM NAC, 5mM NAC, and 10mM NAC. Thoracic aorta rings were isolated from rats for measurements of relaxation responses and Na+/K+-ATPase activity. In the cultured thoracic aorta cells, we measured the currents of KATP channel, the concentration of intracellular calcium and mRNA expression level of KATP channel subunits (KCNJ8, KCNJ11, ABCC8 and ABCC9). RESULTS: The relaxation rate significantly increased in all NAC groups compared to control. Similarly, Na+/K+- ATPase activity also significantly decreased in NAC groups. Outward KATP channel current significantly increased in all NAC groups compared to the control group. Intracellular calcium concentration decreased significantly in all groups with compared control. mRNA expression level of ABCC8 subunit significantly increased in all NAC groups compared to the control group. Pearson correlation analysis showed that relaxation rate was significantly associated with KATP current, intracellular calcium concentration, Na+/K+-ATPase activity and mRNA expression level of ABCC8 subunit. CONCLUSION: Our findings suggest that NAC relaxes vascular smooth muscle cells through a direct effect on KATP channels, by increasing outward K+ flux, partly by increasing mRNA expression of KATP subunit ABCC8, by decreasing in intracellular calcium and by decreasing in Na+/K+-ATPase activity.

Mesenchymal stem cell treatment in hyperoxia-induced lung injury in newborn rats.

BACKGROUND: The aim of this study was to evaluate the effectiveness of tracheally delivered mesenchymal stem cells (MSC) on lung pathology in a hyperoxia-induced lung injury (HILI) model in neonatal rats. METHODS: For the HILI model, rat pups were exposed to 85-95% oxygen during the first 10 days of life. Rats were divided into six groups: room-air normoxia (n = 11); room air, sham (n = 11); hyperoxia exposed with normal saline as placebo (n = 9); hyperoxia exposed with culture medium of MSC (n = 10); hyperoxia exposed with medium remaining after harvesting of MSC (n = 8); and hyperoxia exposed with MSC (n = 17). Pathologic changes, number and diameter of alveoli, α-smooth muscle actin (α-SMA) expression and localization of MSC in the lungs were assessed. RESULTS: Number of alveoli increased and alveolar diameter decreased in the mesenchymal stem cell group so that there were no differences when compared with the normoxia group (P = 0.126 and P = 0.715, respectively). Expression of α-SMA decreased significantly in the mesenchymal stem cell group compared with the placebo group (P < 0001). Green fluorescent protein-positive cells were found in lung tissue from all rats given MSC. Some green fluorescent protein-positive MSC also expressed surfactant protein-C. CONCLUSION: Mesenchymal stem cells became localized in damaged lung tissue, and recovery approximated the room air control.