Biocompatibility of an experimental endodontic sealer (Resil) in comparison with AH26 and AH-Plus in rats: An animal study.

Background. This experimental study sought to assess the biocompatibility of Resil, an experimental epoxy resin-based sealer, in comparison with AH26 and AH-Plus sealers in rats. Methods. Twelve male Wistar rats weighing 400 to 500 grams were evaluated in this experimental study. Four polyethylene tubes containing Resil, AH-Plus, AH26 sealers, and an empty tube were implanted subcutaneously in rats. The degree of inflammation, type of inflammatory cells present, foreign body reaction, quality of connective tissue, and presence of fibrotic capsule were evaluated histopathologically at 7 and 30 days after implanting the tubes to assess the biocompatibility of sealers. Data were analyzed using the Chi-square test. Results. At 7 days, the degree of inflammation in Resil group was almost similar to AH26 group, and 66.7% of rats showed moderate inflammation. AH-Plus group showed less inflammation than Resil and AH26 (50% of rats showed low degree of inflammation), At 30 days, the inflammatory status of all groups was the same, and 83.3% of rats showed very low degree of inflammation. The inflammatory response during the experiment decreased from day 7 to day 30 in all groups. The neutrophil count (P=0.00), fibrotic capsule (P=0.01) and the amount of granulation tissue (P=0.05) significantly decreased from day 7 to day 30 in Resil group. Conclusion. Resil sealer showed appropriate biocompatibility at 7 and 30 days after subcutaneous implantation in rats, comparable to AH26 and AH-Plus. Clinical studies are required to confirm these results.

Efficacy of topotecan nanoparticles for intravitreal chemotherapy of retinoblastoma.

Retinoblastoma (Rb) is the most common intraocular malignancy in children that accounts for approximately 4% of all pediatric malignancies. Since chemotherapy is a widely practiced treatment for Rb, there is a growing interest in developing new and effective drugs to overcome systemic and local side effects of chemotherapy to improve the quality of life and increase the chances of survival. This study sought to fabricate thiolated chitosan nanoparticles containing topotecan (TPH-TCs-NPs) with a view of enhancing drug loading and release control. This research was also designed to assess the ability of TPH-TCs-NPs to improve cell association, increase treatment efficacy in retinoblastoma cells and xenograft-rat-model of retinoblastoma, and overcome current topotecan hydrochloride (TPH) intravitreal administration challenges, including stability loss and poor cellular uptake. Modified ionic gelation method was optimized to fabricate TPH-TCs-NPs and TPH-TMC-NPs (N-trimethyl chitosan nanoparticles containing TPH). We characterized the NPs and quantified topotecan loading and release against a free TPH standard. The efficacy of TPH-NPs was quantified in human retinoblastoma cells (Y79) by XTT and flow cytometry measurement. In addition, Y79 cells were injected intravitreally in both eyes of immunodeficient wistar albino rats to create a xenograft-rat-model to compare the antitumor effectiveness of TPH-NPs and TPH by intravitreal administration. TPH-NPs complexation was confirmed by EDX, FTIR, and DSC techniques. TPH-TCs-NPs and TPH-TMC-NPs had high encapsulation efficiency (85.23 ± 2 and 73.34 ± 2% respectively). TPH-TCs-NPs showed a mean diameter, polidispersity index, and zeta potential of 25±2 nm, 0.21 ± 0.03 and +12 ± 2 mV, respectively. As a function of dose, TCs and TMC NPs were more efficacious than free topotecan (IC50s 53.17 and 85.88 nM, relative to 138.30 nM respectively, P = 0.012). Kruskal-Wallis test showed a statistically significant difference between the groups. Additionally, a significant difference between the tumor control and TPH-TCs-NPs treated group in xenograft-rat-model ( Range of P-value: 0.026 to 0.035) was shown by Bonferroni post hoc test. The current investigation demonstrated enhanced efficacy and association of TPH-TCs-NPs relative to free TPH in retinoblastoma cells and tumor in vitro and in vivo.

Comparison of Topical Pigment Epithelium-Derived Factor (PEDF) with Topical Bevacizumab for Accelerating the Regression of Corneal Neovascularization in an Experimental Model of Rabbit Corneal Angiogenesis.

Purpose: To evaluate the anti-angiogenic effect of topical administration of Pigment epithelium-derived factor (PEDF) on the reduction of corneal neovascularization (NV) in comparison to topical Bevacizumab.Methods: 18 eyes of 18 New Zealand rabbits were enrolled. Corneal NV was induced by a 7-0 silk suture. After suture removal, rabbits were randomly divided into three groups. In every group, one eye randomly treated with topical bevacizumab or topical PEDF or saline for 14 days. The area and length of neovascularization were measured by Image J. Histological studies were done in three groups.Results: After 14 days, the mean decrease of corneal NV length was 1.84 ± 0.17 mm (P < .001) in PEDF group and 1.6 ± 0.07 mm (P < .001) in bevacizumab group which was significantly more than the saline group (P = .001 and P < .001, respectively). There was no significant difference between PEDF and bevacizumab group in the reduction of corneal NV length (P = .85). The mean decrease of corneal NV area was 4.94 ± 0.55 mm2 (P < .001) in PEDF group and 4.23 ± 0.29 mm2 in the bevacizumab group (P < .001). PEDF and bevacizumab significantly decreased corneal NV area in comparison to the saline group (p = .017, p = .001, respectively). The mean decrease of corneal NV area did not show a significant difference between PEDF and bevacizumab groups (P = .72).Conclusion: Topical PEDF might be an effective and safe treatment option as bevacizumab in a short-term use, indicating that it is as good as the standard. However, long-term effect is required to be investigated.

Fabrication, Optimization, and In Vitro and In Vivo Characterization of Intra-vitreal Implant of Budesonide Generally Made of PHBV.

Drug delivery to vitreous in comparison with drug delivery to the other parts of the eye is complicated and challenging due to the existence of various anatomical and physiological barriers. Developing injectable intra-vitreal implant could be beneficial in this regard. Herein, poly(hydroxybutyrate-co-valerate) (PHBV) implants were fabricated and optimized using response surface method for budesonide (BZ) delivery. The acquired implants were characterized in regard to the stability of the ingredients during fabrication process, drug loading amount, and drug release pattern (in PBS-HA-A and in vitreous medium). According to this research and statistical analysis performed, first HV% (hydroxyvalerate) then molecular weight and ratio of PEG as pore former affect respectively release rate and burst strength of BZ with different coefficients. Drug release profile in rabbit eye correlated well with that of in vitro (R2 = 0.9861, p Ë‚ 0.0001). No significant changes were seen in ERG waves, intraocular pressure, and histological studies during the in vivo part of the project. Using 8% HV, 20% PEG/PHBV, and higher molecular weight PEG (i.e., 6000), the optimum formulation was achieved. Toxicity and biocompatibility of the optimized formulation, which were evaluated in vivo, indicated the suitability of design implant for intra-vitreal BZ delivery. Grapical abstract.

Long term features of diabetic retinopathy in streptozotocin-induced diabetic Wistar rats.

Diabetic retinopathy is a complication of diabetes and a leading cause of vision loss among working-age adults. To assess whether the Wistar rat with Streptozotocin (STZ)-induced diabetes is a suitable animal model of human proliferative diabetic retinopathy we evaluated the vascular changes to assess the diabetic retinopathy (DR) stages in this model. After two weeks of intraperitoneal STZ (55 mg/kg) injection in male Wistar rats (270-300 g), they were considered diabetic with persistent blood glucose levels ≥ 16.65 mmol/L. The diabetic and control rats were investigated after 1, 3, 6 and 9 months by electroretinography, Evans blue assay, dextran fluorescence retinal angiography, and retinal histopathological studies. Retinal vascular permeability in the diabetic groups increased significantly in all diabetic groups. The amplitude of a- and b-waves decreased significantly in all diabetic groups compared with the age-matched control groups. The latent time of a-waves in the diabetic groups was delayed at 3 months of diabetes and this delay remained relatively constant till 9 months following the onset of diabetes. Although the latent time of b-wave in the diabetic groups increased slightly, a significant difference was found right at 9 months of diabetes. Vascular density and branching point numbers significantly decreased in the diabetic eyes at 3 and 6 months while they increased at 9 months, which was not significant. Intraretinal hemorrhage and ischemic changes were detected in the half of diabetic rats after 6 months and considered as preproliferative stage of diabetic retinopathy. Although preproliferative changes were detected in all diabetic rats at 9 months, half of them showed vitreous neovascularization attached to retina and retinal folds which can be considered as proliferative stage of DR. Intraretinal hemorrhage, extensive leakage of fluorescein, retinal folds, and vitreous neovascularization were the most prominent findings of severe and proliferative diabetic retinopathy in a fraction of the STZ-induced diabetic rats which were comparable to that of the human patients. STZ-induced diabetic rats can be considered to be a potentially useful model for studies on pathogenesis and treatment of diabetic retinopathy in human.

Histological Changes in the Periosteum Following Subperiosteal Expansion in Rabbit Scalp.

PURPOSE: In intraoral bone grafting, tension-free coverage of the recipient site with periosteal flap results in optimal wound closure. Tissue expansion could be a suitable modality to obtain soft tissue in the oral cavity. The aim of this study was to assess the histology of the periosteum after subperiosteal expansion in the rabbit scalp. MATERIALS AND METHODS: In this animal study, 6 rectangular tissue expanders were placed in the skulls of 6 male white New Zealand rabbits; in 6 control rabbits, an incision was made to the periosteum but no expansion was performed. Three months after the surgeries, the rabbits were sacrificed and tissue samples were stained with hematoxylin and eosin and Masson trichrome. RESULTS: The number of osteoblasts, fibroblasts, and blood vessels and the density of collagen fibers were significantly increased in the experimental group compared with the control group (P < .001). CONCLUSIONS: Subperiosteal tissue expansion in the rabbit scalp markedly increased the histologic components of the periosteum involved in bone regeneration.

Strip meniscometry in dogs, cats, and rabbits.

OBJECTIVE: The purpose of this study was to establish the normal values of strip meniscometry (SM) as a lacrimal function test and to compare the results with Schirmer tear test I (STT I) in dogs, cats, and rabbits. ANIMALS STUDIED: Sixty healthy adult dogs from twelve different breeds (120 eyes), twenty adult healthy domestic shorthair cats (40 eyes) and eighteen adult healthy New Zealand white rabbits (36 eyes) were used in this study. PROCEDURES: Lacrimal function was tested by SM tube in all animals. After 24 h at the same time of day, tear production was measured using STT I. RESULTS: Mean SM and STT I values for all of the dogs, cats, and rabbits were 9.66 ± 2.15 mm/5 s and 15.10 ± 3.06 mm/min; 10.50 ± 0.7 mm/5 s and 11.00 ± 1.41 mm/min; 4.72 ± 1.20 mm/5 s and 4.22 ± 2.47 mm/min, respectively. There was a correlation (r = 0.281; P = 0.018) between SM and STT I values in dogs, but no correlation was observed in cats and rabbits (P = 0.61, P = 0.06). No correlation was found between age of animals and obtained SM values in each species (P > 0.29). Sex had no effect on SM values in each species (P > 0.08). CONCLUSIONS: The result of this study provided the normal clinical values of strip meniscometry as lacrimal function test in three species.

Effect of sintering temperature rise from 870 to 920°C on physicomechanical and biological quality of nano-hydroxyapatite: An explorative multi-phase experimental in vitro/vivo study.

Hydroxyapatite (HA) is a proper scaffold for bone repair, however, it is not of excellent mechanical properties. Most previous studies on the effect of temperature increases were in vitro and had assessed merely improvements of HA's physicomechanical quality. This in vitro/vivo study investigated the effect of temperature increases from 870 to 920°C on physicomechanical and biological quality of Nano-HA. Forty experimentally produced HA disks sintered at 870 to 920°C were prepared (n=20×2). Disks were subjected to Vickers microindentation test (1 disk from each group divided into 4 quarters), Fourier transform infrared spectroscopy (1 disk), X-ray diffraction (XRD) [1 disk together with non-sintered HA], field emission scanning electron microscopy (FSEM, 1 disk from each group together with non-sintered HA), cell seeding and SEM assessment (2 disks), MTT assay over 4 different time periods (16 quadrants of 4 disks from each group), 6 one-thirds of 2 disks from each group for immunocytochemical (ICC) assay, and 8 disks from each group [as well as non-sintered HA] for the animal study (implantation in 4 sockets in 8 rabbits [32 specimens], histomorphometry, and computerized tomography) over two time periods. Quantitative data were analyzed statistically (α=0.05). Vickers microhardness increased from 63.7±11.9 in the 870 group to 153.4±104.7 in the 920 group (P=0.057). XRD indicated more regular crystal patterns in sintered groups compared to non-sintered nanoHA. FSEM showed larger crystals in the 920 group compared to 870 and non-sintered nanoHA. Expression of osteocalcin, osteonectin, and RUNX2 genes were more visible in ICC samples of the 920HA group. In MTT, cell numbers increased in all groups significantly (P=0.000), with no between-group differences (P>0.3). In rabbit experiments, the extent of 'newly formed bone' increased significantly over time (two-way ANOVA, P=0.000), reaching 39.5%, 46.4%, and 77.5% in the groups non-sintered HA, 870, and 920, respectively. The 920°C-sintered nanoHA induced the highest bone formation (P=0.000). Increasing the temperature of nanoHA sintering from 870 to 920°C can improve its physicomechanical properties and bone formation potential.

Intercellular adhesion molecule-1 (ICAM-1) gene polymorphism and endometriosis in northern Iran.

PURPOSE: Endometriosis is a chronic pleomorphic disorder with pelvic or systemic manifestations, and is characterized by the presence of endometrial glands and stroma. It is generally considered to involve genetic, environmental, immunological, angiogenic and endocrine processes. The aim of this study was to evaluate the frequency of intercellular adhesion molecule-1 (ICAM-1) polymorphism at position 241 in exon 4 of the ICAM-1 gene in patients with endometriosis and in healthy control subjects in northern Iran. METHODS: A total of 84 unrelated patients and 120 consecutive unrelated healthy controls from the northern Iran were recruited for the study. ICAM-1 codon 241 polymorphism analysis was performed by two independent PCR reactions, based on the two set of oligoprimers specific for Arg (AGG) or Gly (GGG) coding sequence, respectively. RESULTS: Genotype distributions of ICAM-1 gene show significant difference between patients and controls. The R241 allele was detected in 23% of endometriosis patients and in 6% of controls (P = 0.001; odds ratio 4.67; 95% confidence interval 1.81-12.07). Comparing patients with different stage of endometriosis, we found a trend to higher frequency of R241 in patients with stage IV (65 vs 6%; P < 0.0001). CONCLUSION: Our results suggest that ICAM-1 polymorphism in codon 241 is associated with the development of endometriosis susceptibility in the population of northern Iran.