Molecular mechanisms of poor osseointegration in irradiated bone: In vivo study in a rat tibia model.

AIM: Radiotherapy is associated with cell depletion and loss of blood supply, which are linked to compromised bone healing. However, the molecular events underlying these effects at the tissue-implant interface have not been fully elucidated. This study aimed to determine the major molecular mediators associated with compromised osseointegration due to previous exposure to radiation. MATERIALS AND METHODS: Titanium implants were placed in rat tibiae with or without pre-exposure to 20 Gy irradiation. Histomorphometric, biomechanical, quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay analyses were performed at 1 and 4 weeks after implantation. RESULTS: The detrimental effects of irradiation were characterized by reduced bone-implant contact and removal torque. Furthermore, pre-exposure to radiation induced different molecular dysfunctions such as (i) increased expression of pro-inflammatory (Tnf) and osteoclastic (Ctsk) genes and decreased expression of the bone formation (Alpl) gene in implant-adherent cells; (ii) increased expression of bone formation (Alpl and Bglap) genes in peri-implant bone; and (iii) increased expression of pro-inflammatory (Tnf) and pro-fibrotic (Tgfb1) genes in peri-implant soft tissue. The serum levels of pro-inflammatory, bone formation and bone resorption proteins were greater in the irradiated rats. CONCLUSIONS: Irradiation causes the dysregulation of multiple biological activities, among which perturbed inflammation seems to play a common role in hindering osseointegration.

Angiotensin(1-7) attenuates tooth movement and regulates alveolar bone response during orthodontic force application in experimental animal model.

BACKGROUND: Renin-angiotensin system and its ACE2/Ang(1-7)/Mas receptor axis regulates skeletal response to multiple physiological and pathological conditions. Recent research suggested a vital role of Ang(1-7) in regulating alveolar bone metabolism and remodeling. In this context, this study evaluated the effects of the Ang(1-7)/Mas receptor axis on orthodontic tooth movement (OTM) and the alveolar bone response to mechanical load. METHODS: A coil spring was placed between the right maxillary first molar and the anterior tooth of Wistar rats to apply bidirectional mechanical force. Ang(1-7) with or without a specific Mas receptor antagonist (A779) was infused using subcutaneous osmotic pumps (200 and 400 ng/kg/min: respectively). Animals were killed after 5 and 14 days from the OTM procedure after the clinical evaluation of tooth movement and mobility. Morphometric analysis of alveolar bone structure was conducted using micro-CT and the histological picture was evaluated after H&E staining. Moreover, collagen fiber distribution was assessed using Picro-Sirius red stain. In addition, bone samples were collected from the pressure and tension sites around the anterior tooth for gene expression analysis. RESULTS: Ang(1-7) infusion suppressed the tooth movement and mobility after 14 days of the orthodontic force application. Additionally, Ang(1-7) infusion preserved the morphometric and histological structure of the alveolar bone at pressure and tension sides. These effects were abolished by adding A779 infusion. Collagen fiber distribution was dysregulated mainly by the A779 Mas receptor blockage. Ang(1-7) affected the bone formation, remodeling- and vascularity-related genes in the pressure and tension sides, suggesting a prominent suppression of osteoclastogenesis. Ang(1-7) also improved osteoblasts-related genes on the tension side, whereas the osteoclasts-related genes were augmented by A779 on the pressure side. CONCLUSION: Collectively, the activation of Ang(1-7)/Mas receptor axis appears to hinder tooth movement and regulates alveolar bone remodeling in response to mechanical force.

Inflammatory response to epoxy resin and calcium silicate sealers preheated with different temperatures: an in vivo study.

OBJECTIVE: To determine the impact of heat exposure of different sealers on inflammatory cytokine secretions and tissue response in vivo. MATERIALS AND METHODS: Silicone tubes were prefilled with epoxy resin (ER) or calcium silicate (CS) sealers, preheated at 37, 60, or 120 °C, and implanted in rat subcutaneous site. Peri-implant exudate and tissue were analyzed after 1 and 4 weeks for cytokine secretions and tissue organization. RESULTS: At 1 week, 120 °C-preheated CS and ER induced higher secretions of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), respectively, as compared to sham/empty tube groups. At 4 weeks, whereas TNF-α secretion was reduced in CS, it increased in ER group, particularly for 120 °C. Both sealers revealed high IL-6 after 4 weeks as compared to sham/empty tube, and generally, higher IL-6 secretions were associated with ER. Histology at 1 week revealed lower degree of inflammatory infiltrate in the groups of the highest preheating temperature (120 °C). Nonetheless, at 4 weeks, whereas fibrous capsule area and inflammatory infiltrate remained low in the CS120 group, they were high in ER120. CONCLUSION: Preheating ER sealer to 120 °C induced high and prolonged secretion of proinflammatory cytokines (TNF-α and IL-6), whereas this effect was transient for the CS sealer. This was associated with increased fibrous capsule and inflammatory infiltrate in response to 120 °C-preheated ER. CLINICAL RELEVANCE: Heat-induced changes in sealer properties alter the inflammatory response in vivo, which may affect the clinical outcome. This will not only help appropriate selection of obturation technique for different sealers, but also for optimizing the properties of new generation of sealers.

The Effectiveness of Nigella sativa and Ginger as Appetite Suppressants: An Experimental Study on Healthy Wistar Rats.

Background: Obesity is a global pandemic that is associated with high morbidity and mortality. Natural herbs are commonly used for weight reduction and appetite suppression. Therefore, we aim to investigate the role and mechanism of Nigella sativa (NS) and ginger on weight reduction and appetite regulation. Methods: This experimental study was performed at Imam Abdulrahman Bin Faisal University. Twenty-five female rats were distributed into 5 groups: NS (oral 1000mg/kg), Ginger (500 mg/kg), NS-ginger (both interventions), a positive control (intraperitoneal 50 µg/kg Liraglutide), and a negative control. Each intervention was given for 9 weeks. Food intake and body weight were assessed weekly. Serum lipid profile and peptides involved in appetite control (cholecystokinin (CCK), glucagon-like peptide 1(GLP-1), gastric inhibitory polypeptide (GIP), ghrelin, peptide YY, and orexin) were assayed at the end of the experiment. Results: None of the interventions showed a statistically significant difference regarding food consumption or weight gain (p > 0.05). However, the three interventions significantly reduced total cholesterol (TC), NS and NS-ginger significantly increased HDL, NS increased ghrelin and ginger increased orexin. Conclusion: The present dose and duration of NS, ginger, or in combination did not demonstrate a significant change in body weight or food consumption in comparison to the negative or positive controls. However, NS or ginger has improved the lipid profile by reducing TC and increasing HDL. In addition, NS or ginger can influence some of the peptides involved in appetite regulation such as the increase in ghrelin induced by NS and the reduction of orexin induced by ginger. We believe that these latter effects are novel and might indicate a promising effect of these natural products on appetite regulation.

Assessing the Impact of Alopecia on Quality of Life, Depression, and Self-Esteem in Saudi Arabia.

Objectives The objective of this study is to assess the effects of alopecia on quality of life, depression, and self-esteem in the Eastern Province of Saudi Arabia. Methods We made a questionnaire that included sociodemographic data, type of alopecia, medical aid sought, and whether they benefited from it or not. The study uses the Dermatology Life Quality Index, Patient Health Questionnaire-9, and a single-item self-esteem scale to assess the quality of life, depression, and self-esteem, respectively. Results The questionnaire was completed by 403 individuals in total, and after applying the exclusion criteria (only Saudis, from the Eastern Province), 231 participants were included in this study. Of the participants, 49.4% had hereditary baldness and only 9.5% benefited from treatment. Of the patients, 52.4% had higher levels of depression, and 18.2% had an effect on their life. Patients with a moderate or greater effect on their lives had a significant relationship with hereditary baldness. Younger age, being female, being married, having lower income, and having hereditary baldness were significantly associated with higher depression levels (p = <0.05). The study found that as age increased, depression levels decreased and self-esteem scores increased. Depression was linked to lower quality of life, while self-esteem was linked to both lower quality of life and higher depression levels. These factors are interrelated, with age influencing their relationship. Conclusions The results of the study highlight the significant occurrence of depression and decreased quality of life among patients who have alopecia, particularly those with hereditary baldness. It is crucial to provide psychological assistance and counseling to enhance their mental health and overall wellness.

Potential Antigenic Candidates for the Development of Peptide-Based Vaccines to Induce Immunization against Helicobacter pylori Infection in BALB/c Mice.

Helicobacter pylori (H. pylori) has been identified as a group-1 definite carcinogen. As of yet, there is no available vaccine for this microorganism. Our study aimed to identify antigenic peptides in H. pylori using an in silico proteomic approach, and to evaluate their effectiveness as potential vaccine candidates. Four different peptide sequences were prioritized using the reverse vaccinology, namely, CagA1, CagA2, VacA, and SabA. Peptides emulsified with Freunde's adjuvant were used to immunize BALB/C mice. Subcutaneously immunized mice were challenged by oral administration of H. pylori. IgG, IgA, IL4, and IL17 were detected in mice sera. Histopathology of the dissected stomach of vaccinated and control mice were assessed using H&E stain. IgG was significantly higher in mice vaccinated with SabA. IL-4 was significantly increased in CagA1, CagA2, VacA, and SabA vaccinated mice compared to the adjuvant group. Additionally, histopathological examination of gastric tissue showed a protective effect in the vaccinated groups compared to adjuvant and PBS groups. Our findings indicate a promising effect of the tested epitopes, particularly the SabA antigen, to induce an immune response against H. pylori.

Oral Intragastric DMBA Administration Induces Acute Lymphocytic Leukemia and Other Tumors in Male Wistar Rats.

BACKGROUND: Animal models of blood cancer are important tools to study these malignancies and also screen for novel therapeutic agents. Evidence from past research on the carcinogenic properties of 7,12-dimethylbenz[a]-anthracene (DMBA) was provided by a handful of studies. However, recent literature on DMBA carcinogenic activity and the underlying mechanisms is scarce. OBJECTIVE: The aim of this study was to develop a chemical model of leukemia using DMBA. Male Wistar rats (6 weeks old) were administered 1.5 mg of DMBA dissolved in sesame oil in biweekly doses using oral intragastric intubation. MATERIALS AND METHODS: Frequent complete blood counts and blood smear morphology assessment were used to assess the development of leukemia, while gross pathology and histopathology staining were used to evaluate malignancy development. RESULTS: The results showed that only 4% of rats developed acute lymphocytic leukemia. Interestingly, 36% of the rats developed tumors (parotid tumors [24%] and fibrosarcomas [12%]). CONCLUSION: These results suggest the pleiotropic potential of DMBA in the induction of multiple types of malignancies, including leukemia. This could be used as a model to validate therapeutic targets for leukemia and other induced malignancies.

Caffeine Consumption Influences Lidocaine Action via Pain-Related Voltage-Gated Sodium Channels: An In Vivo Animal Study.

Several factors might influence the duration and efficiency of local anesthesia. This study investigates the effect of habitual caffeine intake on lidocaine action and explores the potential involvement of voltage-gated sodium channels in the interaction effect. Wistar rats were divided into four groups: (i) control (Ctrl), (ii) lidocaine intraplantar injection (LIDO), (iii) habitual caffeine intake (CAF), and (iv) lidocaine intraplantar injection and habitual caffeine intake (LIDO + CAF). Behavioral assessments, consisting of a paw pressure test for mechanical pressure sensation and a paw withdrawal latency test for thermal pain sensation, were performed at 0, 30, 60, and 90 minutes following lidocaine injection and after 10, 11, and 12 weeks of CAF intake. Pressure sensation was significantly reduced in the LIDO + CAF group compared with the control group. Moreover, the LIDO + CAF group exhibited reduced sensation compared to LIDO alone group. The LIDO + CAF combination exerted a synergistic effect at 30 and 60 minutes compared with the control. This synergistic effect was noted at 60 minutes (11 weeks of CAF intake) and at 30 minutes (12 weeks of CAF intake) compared with LIDO alone. Augmented thermal pain-relieving effects were observed in the LIDO + CAF group at all weeks compared to the control group and at 10 weeks compared to LIDO alone group. The molecular analysis of dorsal root ganglia suggested that CAF upregulated the mRNA expression of the Nav1.3, Nav1.7, and Nav1.8 sodium channel subtypes. Chronic caffeine consumption potentiates the local anesthetic action of lidocaine in an experimental animal model through mechanisms that involve the upregulation of voltage-gated sodium channels in the dorsal root ganglia.

Caffeic Acid Phenethyl Ester reduces Pro Inflammatory Cytokines in Moderate Swimming Test in Growing Rats Model.

BACKGROUND: Caffeic acid phenethyl ester (CAPE) is a naturally occurring polyphenolic concentrated in propolis of honeybee hives. CAPE has been shown various physiological and pharmacologic properties. The aim of the present study was to investigate the effects of CAPE on proinflammatory markers in growing rats by performing the moderate swimming test. METHODS: A total number of 21 male Wistar albino rats were separated into three groups (n = 7): sedentary: negative control group; exercise: positive control group received vehicle orally and exercise + CAPE: CAPE treated group: treated with CAPE (20 mg/kg) orally 30 min before exercise, for 5 days. The animals were left free to swim in the tank, 20 minutes/day for 5 days. At 24 hours after finishing the experiment, rats were euthanised and blood was collected to analyze the level of serum interleukin IL-6 and tumor necrosis factor-α (TNF-α). RESULTS: Growing rats subjected to the moderate swimming test and in those treated with CAPE showed a lower level of TNF-α compared to the negative control. More interestingly, the one-way ANOVA data demonstrated a decreased level of proinflammatory IL-6 in the CAPE-treated group compared to the negative control. CONCLUSION: Results of this study indicate that short-term administration of CAPE may modulate proinflammatory cytokine profiles during moderate exercise and may serve to boost the anti-inflammatory effects of exercise. Further studies are needed to evaluate the efficacy and safety of long-term administration of CAPE as an adjective anti-inflammatory agent.

Stem-cell therapy for ovariectomy-induced osteoporosis in rats: a comparison of three treatment modalities.

Background: Recent studies have shown that ovariectomy-induced osteoporosis in rats can be reversed by infusion of osteoblasts cultured from mesenchymal stem cells (MSCs). This study compares the influence of MSCs, osteoblasts, and exosomes derived from osteoblasts for the treatment of osteoporosis. Methods: Osteoporosis was induced in 40 female Sprague Dawley rats by performing ovariectomy. After 12 weeks, bone marrow was harvested and MSCs separated from bone-marrow aspirate as described by Piao et al. After 15 days, autologous osteogenically differentiated cells from the MSCs were available. Exosomes were isolated from osteoblasts by modification of the technique described by Ge et al. MSCs and osteoblasts (106 cells in 0.5 mL normal saline) and exosomes (100 µg protein) were injected into the tail veins of the animals. Animals were euthanized after 12 weeks and femurs and lumbar spines dissected and analyzed using high-resolution peripheral quantitative computed tomography. Results: When compared to the control group, osteoblast-treated animals showed significant differences in all parameters compared, with P-values ranging between <0.002 and <0.0001. Comparison among osteoblasts, MSCs, and exosomes, showed that osteoblasts had positive and statistically significant new-bone formation. The comparison for the spine was similar to the distal femur for osteoblasts. Conclusion: This study showed robust positive bone-forming changes after osteoblast injection in the distal femur and the spine when compared to controls, MSCs, and exosomes.

Effects of cisplatin chemotherapy on the osseointegration of titanium implants.

PURPOSE: The effect of chemotherapy on the osseointegration of dental implants has received less interest compared with radiotherapy. Thus, the aim of the current study was to investigate the effect of cisplatin chemotherapy on the osseointegration of dental implants in a rabbit model. MATERIALS AND METHODS: Sixteen New Zealand White rabbits were randomly assigned to two groups of treatment of either cisplatin at 2.5 mg/kg/week for 4 weeks (n = 8) or placebo (n = 8), in which the first dose was administered 2 days prior to the surgical procedure. Each rabbit received one titanium dental implant inserted in the right distal femoral condyle. Four rabbits from each group were sacrificed 4 and 8 weeks after implant insertion. Osseointegration of the dental implants was analysed using micro-computed tomography and histomorphometric evaluation. RESULTS: Analysis of micro-computed tomography data and histomorphometric data showed that the osseointegration parameters, including the ratio of bone volume to total volume (BV/TV) and bone-implant contact (BIC%) for the cisplatin group, were significantly lower compared to the control group at 4 and 8 weeks. (P ≤ 0.05). CONCLUSION: Cisplatin chemotherapy had a negative effect on the osseointegration of dental implants when inserted throughout the chemotherapeutic regimens in a rabbit model.