Diazinon exposure reduces bone mineral density in adult and immature rats: A histomorphometric and radiographic study.

Diazinon has been widely used as a domestic and agricultural pesticide. This study examined the effects of diazinon on bone mineral density (BMD) of mature and immature rats. For this purpose, 24 adult Wistar rats (male; 8 weeks old) were initially divided into four groups (n = 6). Corn oil was used as the control while diazinon at 15, 30, and 45 mg/kg in corn oil was given to mature rats via gavage per day. Since these dosages were lethal for the immature rats, 12 immature Wistar rats (male; 4 weeks old) (n = 6) were gavaged with corn oil as control and 5 mg/kg of diazinon in corn oil. The animals were sacrificed on day 28 with their left femur bones removed for histomorphometric studies. BMD was measured in the right femur, using standardized radiographs in the femoral head, femoral neck, greater trochanter, and shaft. The Image J Program was used for measuring the bone lamellae and epiphyseal growth plates. The results of this study for the first time revealed that diazinon reduced BMD in both adults and immature rats. Diazinon exposure was associated with diminished trabecular and cortical bone density. Correspondingly, our results indicated that in immature rats, DZN led to the reduction in the epiphyseal growth plate width, both in the proliferation and hypertrophic zones. These results suggested that diazinon might be associated with impaired bone longitudinal growth as well as bone metabolism in adults.

Meiotic initiation in chicken germ cells is regulated by Cyp26b1 and mesonephros.

Our knowledge of mechanisms involved in the meiosis of chicken germ cells is very limited. In mammalian fetal ovaries, the onset of meiosis is dependent on retinoic acid and subsequent upregulation of the Stra8 gene. To clarify the mechanism of meiotic initiation in chicken germ cells, we investigated the role of Cyp26b1, a retinoic acid-degrading enzyme. The Cyp26b1-inhibitor, ketoconazole was used to treat the ex vivo-cultured stage 36 gonads/mesonephroi. Then, the progression of meiosis was studied by histological and immunohistochemical analysis and the level of the transcript for Stra8 was evaluated by a quantitative reverse transcription-polymerase chain reaction in individual ketoconazole-treated gonads after 6 days in culture. The results revealed that meiosis was induced in both testes and right ovary upon inhibition of Cyp26b1 in the ex vivo-cultured gonads, despite downregulation of Stra8 messenger RNA in the treated gonads. Also, meiosis was observed only when mesonephros was cultured alongside the left ovary. These findings demonstrate that in chicken, Stra8 is not the only factor for the entrance into meiosis, and Cyp26b1 and mesonephros play critical regulatory roles for the sex-specific timing of meiotic initiation in birds.

Effect of swim bladder matrix treated with hyaluronic acid on wound healing: an animal model evaluation.

OBJECTIVE: To investigate the potential restorative effects of the white fish (Rutilus frisii kutum) swim bladder matrix (FSBM) treated with hyaluronic acid (HA) in the repair of skin wounds in an animal model. METHOD: Wistar rats were used to investigate the repair function of FSBM as a biological scaffold. Rats were given four round wounds on their back. Wounds were divided into four groups: control, acellular fish swim bladder matrix (AFSBM), HA and AFSBM impregnated with HA (AFSBM-HA). Macroscopic and histological studies in wound healing were investigated on days three, five and seven after injury. RESULTS: The AFSBM-HA group showed a rapid reduction in wound area compared with the other groups, indicating faster wound healing (p<0.001). At day seven after injury, the AFSBM group showed a faster process in epidermal layer formation and angiogenesis compared with the control group (p<0.001). In the AFSBM-HA group, in addition to the reduction of inflammatory cells density, a significant increase in the number of fibroblast cells and collagen synthesis was observed. An elevation in collagen synthesis and angiogenesis was also observed in the HA group compared with the control group. CONCLUSION: The findings of this study indicate that AFSBM-HA can potentially be used as a biological dressing in wound healing.

A systematic review of decellularized allograft and xenograft-derived scaffolds in bone tissue regeneration.

Bone substitutes are used in nearly half of all musculoskeletal surgeries. The "gold standard" graft is an autograft that is limited by supply and site morbidity. Therefore, allograft sources are the current alternative for clinical practice with some side effects, such as immune responses and risk of disease transmission. In this paper, we have systematically reviewed the development and characterization of decellularized allograft or xenograft-derived scaffolds as bone graft substitutes. The databases of PubMed, Cochrane, Scopus, and Web of Science were searched for experimental studies that investigated the potential of acellular allograft or xenograft-derived scaffold for bone regeneration. The search was finalized on 14 September 2020. The initial electronic database search resulted in a total of 484 studies. During the screening process, 416 studies were excluded due to not meeting the inclusion criteria. Finally, a total of 68 articles were included, in which human or animal tissues have been decellularized for bone tissue generation purposes. Although in most studies, a decellularized bone was used for the generation of a bone scaffold, other decellularized tissues, such as the human amniotic membrane or human adipose tissue, were also used in some researches for this purpose. In 42 studies out of the 68, decellularized bone scaffolds were implanted into in vivo animal models. 8 studies used animal bone tissues as an allograft. 12 studies used human tissues as a xenograft. The studies have shown that decellularized allograft or xenograft scaffolds have high biocompatibility with little or no host response, and can enhance new bone formation. Overall, the results of this study suggest that the decellularized xenograft-derived cancellous bone scaffolds can be considered as alternatives to the autologous bone graft. This systematic review might affect future research directions and the preoperative planning of graft selection.

Bacteria and cancer: Different sides of the same coin.

Conventional cancer therapies such as chemotherapy, radiation therapy, and immunotherapy due to the complexity of cancer have been unsuccessful in the complete eradication of tumor cells. Thus, there is a need for new therapeutic strategies toward cancer. Recently, the therapeutic role of bacteria in different fields of medicine and pharmaceutical research has attracted attention in recent decades. Although several bacteria are notorious as cancer-causing agents, recent research revealed intriguing results suggesting the bacterial potential in cancer therapy. Thus, bacterial cancer therapy is an alternative anticancer approach that has promising results on tumor cells in-vivo. Moreover, with the aid of genetic engineering, some natural or genetically modified bacterial strains can directly target hypoxic regions of tumors and secrete therapeutic molecules leading to cancer cell death. Additionally, stimulation of immune cells by bacteria, bacterial cancer DNA vaccine and antitumor bacterial metabolites are other therapeutic applications of bacteria in cancer therapy. The present study is a comprehensive review of different aspects of bacterial cancer therapy alone and in combination with conventional methods, for improving cancer therapy.

The effects of lead on the development of somites in chick embryos (Gallus gallus domesticus) under in vitro conditions: a histological study.

Lead (Pb) is one of the most abundant toxic metals in the environment that can cause a variety of harmful effects. During embryonic development of vertebrates, somites are temporary organs that give rise to skeletal muscle, cartilage, tendon, endothelial cells, and dermis. In this study, we investigated the effects of lead on the development of somites and their derivatives in chick embryos under in vitro conditions. For this propose, fertilized eggs of Gallus gallus domesticus were incubated until they reached the stage of 15-20 somites. The somites and notochord were isolated and treated with different concentrations of lead acetate (500, 1000, 2000, and 4000 ng ml-1) for 72 h. Our results indicated that high concentrations of lead reduced the nucleus diameter, reduced the synthesis of collagen, inhibited the formation of the cartilage matrix in somite cells, and disturbed the formation and order of myotubes. In conclusion, the results of the current study for the first time indicated the disturbing effects of lead on the development of somites in the chick embryo. Our results revealed that lead disturbed the development of somites in the chick embryo, which suggested that at high concentrations it can cause a serious mortal danger to life.

Development of a demineralized and decellularized human epiphyseal bone scaffold for tissue engineering: A histological study.

Extracellular matrix (ECM) controls cellular behaviors such as proliferation, migration, and differentiation. The decellularized matrix of mammalian tissues has been used as a scaffold for the repair and reconstruction of tissue defects. In this study, for the first time demineralized and decellularized human epiphyseal bone matrix was used as a scaffold for a bone generation. Human epiphyseal bone was demineralized by hydrochloric acid and then decellularized by three methods of physical (slow freezing and snap freeze-thaw), enzymatic (trypsin 0.25%, 18 h) and chemical sodium dodecyl sulfate (SDS),)2.5%, 26 h). The scaffolds were cultured with rat adherent bone marrow cells (RABMC). Then, the histological studies were performed on days 7, 14, 21, and 28 of the culture to observe the distribution and morphology of cells. Bone formation was also investigated using Alizarin red staining. The results of this study indicated that RABMC migrated, proliferated and separated by forming lacuna in this three-dimensional bone scaffold. In addition, the Alizarin red staining indicated the calcium deposition on the scaffold in both bone differentiation and standard culture medium. The natural characteristic of the present bone scaffold, its cell adhesion features and capability to induce bone mineralization, even in the standard culture medium, provides a potentially optimal bone scaffold for bone tissue engineering.

Macrophage lineage phenotypes and osteoclastogenesis--complexity in the control by GM-CSF and TGF-beta.

Bone-resorbing osteoclasts (OCs) derive from macrophage lineage precursors under the potential control of many factors. Addition of macrophage-colony stimulating factor (M-CSF or CSF-1) to murine bone marrow cells gives rise to so-called bone marrow-derived macrophages (BMM); this adherent population can then be quantitatively converted into OC lineage cells when receptor activator of NFkappaB ligand (RANKL) is included. The effect of another CSF, granulocyte macrophage-CSF (GM-CSF), on OC differentiation in vitro is quite complex with both enhancing and suppressive actions being described. We report here that GM-CSF can generate a population of adherent macrophage lineage cells from murine bone marrow precursors (GM-BMM) which is also capable of giving rise to OC lineage cells in the presence of M-CSF and RANKL as effectively as BMM. The degree of this differentiation was surprising considering that GM-BMM are often referred to as immature dendritic cells and that, for both BMM and the GM-BMM, GM-CSF suppressed subsequent OC differentiation governed by M-CSF and RANKL. Unlike for BMM, this GM-CSF-mediated suppression for GM-BMM appeared to be independent of c-fos expression. The effects on bone of another cytokine, transforming growth factor-beta (TGF-beta), are also quite complex although usually found to be stimulatory for OC differentiation. Unexpectedly, we observed that TGF-beta1 also potently suppressed M-CSF+RANKL-driven OC differentiation from both BMM and GM-BMM. Using cells from gene-deficient mice, this inhibition of OC differentiation by both GM-CSF and TGF-beta1 appeared to be independent of endogenous interferon alpha/beta production. It appears therefore that the influence of GM-CSF and TGF-beta on osteoclastogenesis depends on the presence or otherwise of other stimuli such as RANKL and possibly upon the maturation state of the OC precursors. It is proposed that the findings have particular relevance for the control of bone resorption in pathology, for example, in inflammatory lesions.

Detection and properties of the human proliferative monocyte subpopulation.

Peripheral blood monocyte subpopulations have been reported and can give rise to diverse, differentiated phenotypes. A subpopulation(s) of human monocytes can proliferate in vitro in response to macrophage-colony stimulating factor (M-CSF; or CSF-1). This population, termed the proliferative monocyte (PM), is presumably less mature than other monocytes; however, it has not been defined further. Previous studies monitoring the frequency of the slowly cycling PM from different donors indicated that the assay for their reproducible measurement required improvement. We demonstrate that for optimal PM detection, high 5-bromo-2'-deoxyuridine concentrations are required over a delayed and wide time-frame. Surface marker phenotyping by flow cytometry showed that freshly isolated PM are CD14+ and could be distinguished from two other human monocyte subpopulations, namely, the CD14lo CD16+ and CD14lo CD64- subsets. PM express relatively high levels of CD64 and CD33 but have relatively low CD13 expression; they are also c-Fms+ and human leukocyte antigen-DR+. Labeling with carboxyfluorescein diacetate succinimidyl ester (CFSE) enabled the estimation of the number of PM divisions over time. Following CFSE labeling and culture, PM were sorted from the nonproliferating population and shown to have a distinctive, spindle-shaped morphology and higher capacity to form multinucleated, tartrate-resistant acid phosphatase+ cells in the presence of M-CSF and receptor activator of nuclear factor-kappaB ligand. The phenotype and properties of the PM subpopulation were examined as a prelude to determining its role in disease using methods that can be applied to clarify human monocyte heterogeneity.

The proliferative human monocyte subpopulation contains osteoclast precursors.

INTRODUCTION: Immediate precursors of bone-resorbing osteoclasts are cells of the monocyte/macrophage lineage. Particularly during clinical conditions showing bone loss, it would appear that osteoclast precursors are mobilized from bone marrow into the circulation prior to entering tissues undergoing such loss. The observed heterogeneity of peripheral blood monocytes has led to the notion that different monocyte subpopulations may have special or restricted functions, including as osteoclast precursors. METHODS: Human peripheral blood monocytes were sorted based upon their degree of proliferation and cultured in macrophage colony-stimulating factor (M-CSF or CSF-1) and receptor activator of nuclear factor-kappa-B ligand (RANKL). RESULTS: The monocyte subpopulation that is capable of proliferation gave rise to significantly more multinucleated, bone-resorbing osteoclasts than the bulk of the monocytes. CONCLUSIONS: Human peripheral blood osteoclast precursors reside in the proliferative monocyte subpopulation.