Seren Gulsen Giray

Effects of metformin on mammalian target of rapamycin in a mouse model of endometrial hyperplasia.

OBJECTIVE The effects of metformin on S6K1, which is a crucial effector of mTOR signaling, and on endometrium were studied in a mouse model of endometrial hyperplasia induced by unopposed estradiol or tamoxifen. STUDY DESIGN Forty-eight oophorectomized Balb/c mice were randomly assigned to receive saline, tamoxifen citrate (4 mg/kg), 17-beta estradiol hemihydrate (4 mg/kg), metformin (50 mg/kg), tamoxifen citrate (4 mg/kg) with metformin (50 mg/kg), or estradiol (4 mg/kg) with metformin (50 mg/kg) for 3 days. Histological markers of uterotrophy, including luminal epithelial cell height and density of endometrial glands were quantified for each slide. Immunohistochemical expression of PCNA and S6K1 was evaluated. H-score was used for S6K1 expression. Statistical analysis was performed using Students t-test for comparison of two continous variables and one-way ANOVA for comparison of multiple variables. RESULTS Mice treated either with tamoxifen or estradiol had significantly increased density of endometrial glands and epithelial heights compared to vehicle-only or metformin-only group (p<0.001). Addition of metformin to tamoxifen or estradiol treated mice significantly decreased the density of endometrial glands and epithelial cell heights (p<0.05). Addition of metformin to tamoxifen significantly decreased the H-score of S6K1 (p<0.05) and the immunohistochemical expression of PCNA (p<0.05) in uterine lining epithelium, glandular and stromal cells. Addition of metformin to estradiol significantly decreased the H-score of S6K1 (p<0.05) and the immunohistochemical expression of PCNA (p<0.05) in uterine lining epithelium, glandular and stromal cells. CONCLUSION Metformin seems to have possible antiproliferative effects on the endometrium of estradiol or tamoxifen treated mice via inhibiting the mTOR mediated S6K1 activation.

Effects of chronic treatment with valproate and oxcarbazepine on ovarian folliculogenesis in rats

Purpose: We aimed to define the morphologic effects of valproate (VPA) and oxcarbazepine (OXC) on ovarian folliculogenesis in rats.

Fallopian damage induced by organophosphate insecticide methyl parathion, and protective effect of vitamins E and C on ultrastructural changes in rats.

The aim of the present study was to examine the effects of subchronic methyl parathion (MP) administration on lipid peroxidation and fallopian tube damage, and to evaluate the preventive effects of the use of vitamins E and C against toxicity. The experimental groups were: rats treated with corn oil (control group), with 5 mg/kg MP and with 5 mg/kg body weight MP plus vitamins E and C (MP + Vit). The groups were given MP by oral gavage for five days a week for four weeks at a daily dose of 5 mg/kg (MP and MP + Vit) using corn oil as a vehicle. Vitamins E and C were injected at doses of 50 mg/kg intramuscularly and 20 mg/kg intraperitoneally, respectively, just after the treatment with MP in the MP + Vit group. The levels of malondialdehyde (MDA) were determined in rat plasma. Electron microscopic ultrastuructural and histopathological changes in the fallopian tissue were examined. MDA levels were higher in the MP group than in the control group, and lower in the MP + Vit group than in the MP group. MP led to deletions in microvilli and marked loss in kinocillia of surface epithelium. But these marked histopathological findings decreased in the MP + Vit group. Multiple doses of MP administration caused some damage in the fallopian tube, and treatment with vitamins E and C after MP could reduce this effect. Toxicology and Industrial Health 2007; 23: 429—438.

The Effect of Topical Doxycycline in the Prevention of Experimental Tympanosclerosis

Objectives: The aim of this study is to determine the effectiveness of topical doxycycline used in the process of experimental myringosclerosis and tympanosclerosis.

Topical Application of Calcium Channel Blockers to Reduce the Progression of Experimentally Induced Myringosclerosis and Tympanosclerosis

Objectives: This study aimed to evaluate the ability of topically applied calcium channel blockers (diltiazem) to reduce the progression of experimentally induced myringosclerosis and tympanosclerosis.

Activation of vocal fold healing with topical vitamin A in rabbits

Conclusion. The results suggest that vitamin A can prevent scar formation in the vocal fold after surgery. Objectives. This study aimed to evaluate the effects of topically applied vitamin A on healing after vocal fold trauma. Materials and methods. Vocal folds of 20 adult rabbits were traumatized unilaterally. Ten of them were treated with topical application of vitamin A and the others served as controls. All animals were sacrificed after 10 days. Vocal folds were resected for analysis by light microscopy. Results. The untreated vocal folds showed extensive deposition of collagen and fibroblast on light microscopy and vocal folds treated with vitamin A showed less deposition. There was a significant difference between the two groups according to the percentage of collagen and fibroblasts in the lamina propria (p<0.01).

RAD001 (Everolimus) Can prevent tamoxifen-related endometrial and stromal hyperplasia.

The mechanism of tamoxifen-associated endometrial hyperplasia and cancer is not elicited. RAD001 inhibits a target protein in phosphatidyl kinase pathway, which is involved in endometrial hyperplasia and cancer. We investigated whether endometrial hyperplasia can be prevented through inhibition of the target of rapamycin by RAD001. Sixty BALB/c mice underwent oophorectomy and were divided into 6 groups: group 1, placebo group; group 2, tamoxifen-treated (4 mg/kg per 24 hours); group 3, estradiol-treated (4 mg/kg per 24 hours); group 4, RAD001-treated (1.5 mg/kg per 24 hours); group 5, tamoxifen (4 mg/kg per 24 hours)-and-RAD001 (1.5 mg/kg per 24 hours)-treated; and group 6, estradiol (4 mg/kg per 24 hours)-and-RAD001 (1.5 mg/kg per 24 hours)-treated. The count of glands, the length of epithelium, and immunohistochemical staining of proliferating cell nuclear antigen were analyzed. The count of total glands and the epithelial length were 30.8 (7.1) and 126 (43.4) μm, 53 (8.1) and 162.5 (34.8) μm, 65.2 (13.6) and 401.4 (44.0) μm, and 82.0 (5.2) and 444.7 (57.8) μm in the placebo-, the RAD001-, the tamoxifen-, and the estradiol-treated groups, respectively (P < 0.05). Although addition of RAD001 to estradiol did not decrease the count of total glands and the epithelial length, addition of RAD001 to tamoxifen did (43.3 [13.3] and 218.0 [29.2] μm, P < 0.05). The immunoreactive score of proliferating cell nuclear antigen is significantly decreased by the addition of RAD001 to either tamoxifen or estradiol in the epithelial and glandular cells. RAD001 can prevent tamoxifen-associated and estrogen-related endometrial hyperplasias in mice. RAD001 also decreases stromal cell proliferation in the tamoxifen-treated mice.

Dose‐Dependent Immunohistochemical and Ultrastructural Changes After Oral Methylphenidate Administration in Rat Heart Tissue

Methylphenidate, more commonly known as Ritalin, is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder, one of the most common behavioural disorders of children and young adults. Our aims were to investigate dose‐dependent immunohistochemical D2 expression and ultrastructural changes of the rat heart tissue, and to demonstrate possible toxicity of the long‐term and high dose use of the methylphenidate. In this study, 27 female pre‐pubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) and their control groups, were used. They were treated orally with methylphenidate dissolved in saline solution for 5 days/week during 3 months. At the end of the third month, after perfusion fixation, left ventricle of cardiac tissue was removed. Paraffin, semi‐thin and thin sections were collected and immunohistochemical, terminal deoxynucleotidyl transferase‐mediated Dig‐dUTP nick end labelling assay and ultrastructural studies were performed. In conclusion, we believe that Ritalin is dose‐related affecting dopaminergic system to increase heart rhythm and contraction. Thus, this drug may cause degenerative ultrastructural changes in mitochondrial path.

Periosteal adventitia is a valuable bone graft alternative

Background Periosteal adventitia is believed to consist of fibrous tissue without any regenerative potential. This theory results in the assumption that surgically stripped periosteum which is also adventitial has no bone regeneration potential. We decided to test whether the periosteal adventitia is osteoinductive and whether it is suitable for a commonly faced clinical situation in an animal model. Methods This study used 24 femurs from 12 rabbits, which were separated into 3 groups. Lateral femoral condylar cavitary defects were created with a 5 mm drill bit. In group I, the defects were left empty as the control. In group II, the defects were only filled with ceramic graft particles. In group III, the defects were filled with a mixture of ceramic graft particles and autogenous, adventitial, periosteal particles. All animals were sacrificed at the end of the 6th week and were evaluated histologically. Results The microscopy of 3 different histologists suggested that group III had far superior healing when compared to the control group and group II. The statistical evaluation of the histomorphometrically gathered quantitative results revealed a meaningful increase in woven bone and a decrease in fibrous tissue in group III, confirming the histological analysis. Conclusions In this study we observed that the composite graft obtained by mixing ceramics and free adventitial periosteal grafts offers healing potential surpassing both the ceramic-only group as well as the control group. We conclude that adventitial periosteal graft greatly facilitates new bone formation.

Plant Growth Regulator (4-Chlorophenoxy Acetic Acid) Increases Apoptosis in Gonads of Rats without Changing Hormonal Levels

Background/Aims: Plant growth regulators are considered to leave minimal amounts of remnants and therefore cause no significant side effects in humans. In this study, we aimed to investigate the hormonal and histopathological effects of 4-chlorophenoxy acetic acid (4-CPA), a commonly used plant growth regulator, on the gonadal functions of rats. Methods: The study was implemented on 64 Wistar albino rats (20 days old). Forty-eight rats received 4-CPA every day until 50 days of age. The rats were randomized into 4 groups (a control group and three 4-CPA groups with doses of 25, 50 and 100 mg/kg/day); each group was further divided into males and females, making a total of 8 groups. The levels of FSH, LH, testosterone, estradiol, leptin, inhibin-B and neuropeptide-Y were measured. Histopathological examination of the testes and ductus deferens in male rats, and ovaries and uterus of female rats (caspase-3 and -9 immunoreactivity) was performed. Results:Although hormone levels were similar between the groups, rats that received 4-CPA showed significantly higher degrees of apoptosis compared to the control group (p < 0.001) and increased doses of 4-CPA were directly correlated with the amount of apoptosis (p < 0.001). Conclusion: 4-CPA induced apoptosis in the gonads of rats without concurrent changes in plasma hormone levels.