Calvarial bone defects in ovariectomised rats treated with mesenchymal stem cells and demineralised freeze-dried bone allografts

BACKGROUND

The aim of the study was to investigate the ability of a combination of bone marrow mesenchymal stem cells (BM-MSCs) with and without demineralised freeze-dried bone allografts (DFDBAs) to induce bone regeneration in calvarial defects in ovariectomised rats.

MATERIALS AND METHODS

Critical size defects were filled with a combination of DFDBAs and BM-MSCs or BM-MSCs alone. Eight weeks after calvarial surgery, the rats were sacrificed. The samples were analysed histologically and immunohistochemically.

RESULTS

No difference was observed in vascularisation between groups C1 (animals with cranial defect only, control group) and O1 (animals with cranial defect only, ovariectomy group). Intramembranous ossification was observed at a limited level in groups C2 (animals with cranial defect with MSCs, control group) and O2 (animals with cranial defect with MSCs, ovariectomy group) compared to C1 and O1. In group C3 (animals with DFDBAs with MSCs, control group), the fibrous structures of the matrix became compact as a result of a bone graft having been placed in the cavity, but in group O3 (animals with DFDBAs with MSCs, ovariectomy group), the fibrous tissue was poorly distributed between the bone grafts for the most parts.

CONCLUSIONS

We conclude that the insertion of BM-MSCs enhances bone healing; however, the DFDBA/BM-MSC combination has little effect on overcoming impaired bone formation in ovariectomised rats.

Distribution of CD68-, CD8-, MHCI- and MHCII-positive cells in the bull and ram testis and epididymis

The mammalian testis possesses a special immunological environment because of its properties of remarkable immune privilege and effective local innate immunity. The testicular immune privilege protects immunogenic germ cells from systemic immune attack, and local innate immunity is important in preventing testicular microbial infections. Thus, this study aimed to immunohistochemically demonstrate the distribution and localization of CD68-, CD8-, MHCI- and MHCII-positive immune cells in the testes and epididymes. Negative immunoreactivity was detected in the seminiferous tubule epithelium and peritubular myoid cells of the testes upon staining in CD68, CD8 and MHC Class I. Positive CD68 immunoreaction was determined in the Sertoli cells and some Leydig cells. The detection of positive cells for CD8 clearly indicated the presence of lymphocytes. Furthermore, the staining with MHCI intensity was ascertained to vary from weak to moderate in the Sertoli and Leydig cells and connective tissue cells. MHCII-positive immunoreactivity was determined in myoid cells and Leydig cells in the interstitial area. The epithelium of the epididymis showed positive staining for CD68 and CD8, but the stroma displayed a rather weak staining. In the ram epididymis, neither intraepithelial nor interstitial positive reaction was observed for MHCI. In the epididymis, the basal cells displayed a stronger staining for MHCII. In conclusion, these cells not only contribute to local immunity through their direct effects on the quality of fertility in males, but also contribute either directly or indirectly to immune privilege by minimizing the development of both autoimmune reactions and potentially harmful risks.

Morphological Changes Caused by Streptozotocin-Induced Diabetes in the Healthy Gingiva of Rats

BACKGROUND AND OBJECTIVE

Epidemiologic and clinical studies have indicated that diabetes is a risk factor for periodontal disease progression. The aim of the present study was to evaluate the morphological changes of gingiva in streptozotocin diabetic rats.

MATERIAL AND METHODS

30 male Wistar rats that weighed 250-300 g were used in this study. The animals were randomly divided into 2 groups, one with streptozotocin-induced diabetes and another one with healthy (non-diabetic) animals. All rats were sacrificed after 21 days, and their maxillary first molars with surrounding tissues were observed morphological analyses.

RESULTS

In this study, it was observed that the epithelial thickness was greater in the diabetes group, compared to the control group. The statistical comparison of the diabetes and control groups for the thickness of each of the layers of the epithelium demonstrated that the thickness of the keratinized (corneum), granular and basal layers had significantly increased in the diabetic animals. Furthermore, the diabetes group displayed a decrease in the height of the connective tissue papillae, which was found to be statistically insignificant. Another important finding detected in the diabetes group was the congestion of the gingival capillaries, which showed that blood circulation is impaired in diabetes cases.

CONCLUSION

On the basis of the results obtained in this study, it was concluded that streptozotocin-induced diabetes may increase predisposition to periodontal disease by causing morphological changes in the periodontal tissues.

Expression of epidermal growth factor receptors and epidermal growth factor, amphiregulin and neuregulin in bovine uteroplacental tissues during gestation

INTRODUCTION

Growth factors are proteins that bind to specific cell surface receptors that initiate signalling pathways and result in proliferation or differentiation of the affected cells. During gestation, epidermal growth factor receptors (ErbB1-4) and its ligands (epidermal growth factor-EGF, amphiregulin-AREG, neuregulin1-NRG1) play a significant role in differentiation, function and growth of the uterus.

OBJECTIVES

To determine the role of ErbB receptors and EGF, AREG and NRG1 in bovine uteroplacental tissues during gestation.

METHODS

Placentomes and interplacentomal areas from 30 cows from early gestation until near term were analysed by immunohistochemistry.

RESULTS

ErbB receptors and its ligands were observed in uteroplacental tissues and its expression was maintained throughout pregnancy, but ErbB1 receptor did not exist in the caruncular and cotyledonary stromal cells. Besides, caruncular stromal cells did not present with any immune reaction for EGF, AREG and NRG1. Generally, it was observed that total scores for ErbB receptors and its ligands (EGF, AREG and NRG1) had decreased from early to late gestation (p < 0.05).

CONCLUSION

Our study shows the presence of ErbB receptors and its ligands participate in the mid- and late-phases of pregnancy. To our knowledge, this is the first study on the expression of NRG1 during bovine pregnancy. These results indicates that these factors may play a crucial role not only to enable cellular proliferation and differentiation in the uterus throughout gestation, but also to have a potential role in the cellular communication maintained between the embryo/fetus and uterus by the placenta.

Preliminary study of efficacy of hyaluronic acid on caustic esophageal burns in an experimental rat model

BACKGROUND

The aim of this study was to investigate the effectiveness of hyaluronic acid on the prevention of esophageal damage and stricture formation after experimental caustic (alkaline) esophageal injury in rats.

MATERIALS AND METHODS

Twenty-one Wistar albino rats were randomly divided into three groups. A caustic esophageal burn was created following the Gehanno model: Group l (n=7) underwent operation, but no injury; Group 2 (n=7) was injured and left untreated; and Group 3 (n=7) was injured and treated with hyaluronic acid, first topically and then orally by gavage (2×0.3mL; 12.5mg/mL for 7days). The caustic esophageal burn was created by instilling 25% NaOH into the distal esophagus. All rats were euthanized on day 22 for evaluation. The efficacy of hyaluronic acid treatment was assessed histopathologically and biochemically via blood determination of the total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and sulfhydryl group (SH) and lipid hydroperoxidase (LOOH) levels. Statistical analyses were performed.

RESULTS

Weight gain was significantly lower in Group 2 than in the other two groups (P<0.05). The mean stenosis index, histopathologic damage score, TAS, TOS, OSI, and SH and LOOH levels were higher in Group 2 than in the other two groups. The mean stenosis index, inflammation, TAS, SH and OSI in Group 2 were significantly different than those in the other two groups (P<0.05).

CONCLUSION

Hyaluronic acid treatment is effective in treating damage and preventing strictures after caustic esophageal burn in rats.

Expression of the erbB/HER receptor family in the bovine uterus during the sexual cycle and the relation of this family to serum sex steroids

Our study was designed to investigate immunohistochemically the expression of the receptors of the erbB/HER family (erbB1/HER1, erbB2/HER2, erbB3/HER3, erbB4/HER4) in the bovine uterus during the follicular and luteal phases of the sexual cycle, and the relation to ovarian sex steroids. The stage of the estrous cycle in 30 Holstein bovine was assessed based on the gross and histological appearance of the ovaries and uterus, and on blood steroid hormone levels. Tissue samples taken from the uterus were fixed in 10% formaldehyde for routine histological processing. Positive membrane and cytoplasmic staining of varying intensity were determined in the uterus during the follicular and luteal phases of the sexual cycle for erbB/HER receptors in luminal and glandular epithelial cells, connective tissue, smooth muscle and vascular endothelial and smooth muscle cells. We demonstrated that the apical and basal membranes of luminal epithelial cells and the apical membrane of glandular epithelial cells reacted with erbB1/HER1 and erbB2/HER2 during both the follicular and luteal phases. The reaction for erbB3/HER3 and erbB4/HER4 was stronger in the cytoplasm of luminal and glandular epithelial cells, but was heterogeneous. During both the follicular and luteal phases, the percentage and staining intensity of luminal and superficial glandular epithelial cells reacting positively with the receptors erbB1/HER1, erbB2/HER2, erbB3/HER3 and erbB4/HER4 were greater than those of deep glandular epithelial and connective tissue cells (p < 0.05). We demonstrated that the expression of the erbB/HER receptor family varied with different cell types in the bovine uterus during the follicular and luteal phases.

The role of estrogen receptors, erbB receptors, vascular endothelial growth factor and its receptors, and vascular endothelial growth inhibitor in the development of the rat mammary gland

We identified the localization and distribution of cell-specific epidermal growth factor receptors (EGFRs: erbB-1, erbB-2, erbB-3, erbB-4), vascular endothelial growth factor (VEGF), VEGF receptors [VEGFRs: VEGF-R1 (flt-1), VEGF-R2 (flk-1/KDR), VEGF-R3 (flt-4)], vascular endothelial growth inhibitor (VEGI), and estrogen receptor (ER), and determined whether or not these growth factors in rat mammary glands are functional. Thirty-five adult female Spraque-Dawley rats were randomly divided into five groups, each of which were at the 7th, 14th, and 21st day of pregnancy; 7th day post-delivery; and 7th day after weaning. It was determined that erbB, VEGF and its receptors, VEGI, and ER stained at different intensities. Intense staining was observed, in particular, in erbB receptors during pregnancy and involution, and also in VEGF and its receptors during lactation, while ER stained during the last periods of pregnancy and lactation. In conclusion, the expression of erbB, VEGF and its receptors, and ER were determined at varying intensities at different sites of the mammary gland during pregnancy, lactation, and involution periods.

Distribution of estrogen receptor α and progesterone receptor B in the bovine oviduct during the follicular and luteal phases of the sexual cycle: an immunohistochemical and semi-quantitative study

The aim of our study was to determine the distribution of estrogen receptor α (ERα) and progesterone receptor B (PR-B) in the bovine oviduct during the follicular and luteal phases. Bovine oviducts from 23 animals were obtained from a local slaughterhouse. Blood samples from these animals also were taken before death to measure estrogen and progesterone levels. The serum levels of estradiol-17β and progesterone changed during the estrous cycle. Tissue distribution of ERα and PR-B was examined using immunohistochemical techniques and the results showed that ERα and PR-B were stained in nuclei of cells and could be detected in all compartments along the entire oviduct during both the follicular and luteal phases. During the follicular phase, no significant differences were found between ERα and PR-B distribution (p < 0.05), while significant differences were found between ERα and PR-B during the luteal phase (p < 0.05). We results indicated that the frequency and intensity of ERα and PR-β immunoreactivity in the oviduct of bovines varied according to the oviductal cell types and the phases of the sexual cycle.

The effect of dexamethasone on gastric mucosal changes following sialoadenectomy in rat

In this study, dexamethasone-induced gastric lesions were studied in rats that had undergone sialoadenectomy. The ultrastructural changes developed during the study were detected by electron microscopically, while blood serum and stomach epidermal growth factor (EGF) concentrations were measured by RIA. The result of the study showed that gastric lesions were correlated with gastric mucus secretion and both serum and mucosa EGF levels. After the administration of dexamethasone, it was found that sialoadenectomy significantly (p<0.01) raised the incidence of stomach lesions (p<0.01), and a significant increase in mucus secretion was also found. Additionally, the serum and gastric mucosal EGF levels fell after sialoadenectomy when compared to normal rats. The most important gastric mucosal changes were observed in rats treated with dexamethasone and those both sialoadenectomised and treated with dexamethasone.

Effects of tamoxifen administration in rat vaginas: an ultrastructural and light microscopy study

BACKGROUND

Tamoxifen (TAM) inhibits the initiation of carcinogen induced rat mammary tumours and is administrered for extended periods after the initiation of carcinogenesis. It is also a widely used treatment for breast and gynaecological cancer.

OBJECTIVE

In this study, we aimed to investigate tamoxifen (TAM) administration on vagen development in rats.

MATERIAL & METHODS

Twenty sexually mature and pregnant Wistar albino rats were chosen as the animal model. They were divided into two groups. Group I: Control group, Group II: Tamoxifen applied (between gestational day 16 and 21 days); 100 microg tamoxifen citrate (TAM) in 0.05 ml saline subcutaneously per day/animal. After birth, all female rats were sacrificed on the 60th day and were taken vaginal tissue. Transmission electron microscopy and light microscopy have been used to study changes to the vaginal epithelium.

RESULTS

A statistically significant reduction of birth body weight was noted in the experimental group of rats when compared to the control group (P < 0.05). We saw increase in the thickness of the epithelium layer and irregularity and disappearance of microscopic papilla, cytoplasmic vacuolation in cells of the surface layer, thin and irregular basal membrane, lateral junction of cells were destroyed in the TAM treated groups. In conclusion, neonatal tamoxifen administration affects vagina epithelium and lead to decreasing birth body weight and vaginal adenosis.

The effects of sialoadenectomy & flutamide on skin development

BACKGROUND

Epidermal growth factor is a low molecular weight polypeptide with 53 amino acids and is known to stimulate cell proliferation and differentiation in a wide range of tissues. The submandibulary gland in the mouse is a rich source of epidermal growth factor and decreased plasma epidermal growth factor levels have been observed after sialoadenectomy (removal of the submandibular glands). Furthermore. there is evidence that epidermal growth factor stimulates spermatogenesis and reverses antiandrogen induced cryptorchidism.

OBJECTIVE

In the present study, the teratogenic effects of sialoadenectomy and antiandrogen (flutamide) administration on rat skin were investigated histologically.

MATERIALS & METHODS

Thirty Spraque-Dawley female rats were separated into three groups (n = 10), a control (sham-operated) and two experimental groups. The first experimental group of rats were subjected to sialoadenectomy in order to create maternal EGF deficiency one month before copulation. The second experimental group of rats were given flutamide (10 mg/100 g) for ten days during pregnancy. Three months after birth, a penile skin biopsy was taken from respective offspring in all groups.

RESULTS

A statistically significant reduced body weight and length were noted in the first group of litters (maternal EGF deficient) and in the flutamide administered group when compared to the control group. Atrophic epidermis and dermal adnexa were observed histologically as the teratogenic effects of sialoadenectomy and flutamide administration on rat skin development.

CONCLUSION

Epidermal growth factor is a key hormone for skin development and antiandrogen administration may insult this process by interfering with epidermal growth factor metabolism.

Whole-body microwave exposure emitted by cellular phones and testicular function of rats

This study investigated whether there are adverse effects due to microwave exposure emitted by cellular phones in male rats. Eighteen Wistar Albino rats were separated into three groups, a sham group and two experimental groups. The rats were confined in Plexiglas cages and cellular phones were placed 0.5 cm under the cages. In the first experimental group, cellular phones were in standby position for 2 h. In the second experimental group, phones were turned to the speech position three times each for 1 min duration over 2 h. Rats in the first and second experimental groups were exposed to microwaves emitted by phones for 2 h/day for a duration of 1 month. After the last exposure the rats were killed. Brain, eyes, ears, liver, heart, lungs, stomach, kidneys, testes, small and large intestines and skin of the rats were observed histologically. The decrease of epididymal sperm counts in the speech groups were not found to be significant (P > 0.05). Differences in terms of normal and abnormal sperm forms were not observed (P > 0.05). Histological changes were especially observed in the testes of rats of the speech groups. Seminiferous tubular diameter of rat testes in the standby and speech groups was found to be lower than the sham group (P < 0.05). Rectal temperatures of rats in the speech group were found to be higher than the sham and standby groups (P < 0.05). The rectal temperatures of rats before and after exposure were also found to be significantly higher in the speech group (P < 0.05). Specific absorption rate (SAR) was determined as 0.141 W/kg.