Immune system and tumor microenvironment in early-stage breast cancer: different mechanisms for early recurrence after mastectomy and chemotherapy on ductal and lobular types.

Background: The most common type of breast cancer is the ductal type (IDC), followed by lobular type (ILC). Surgery is the main therapy for early-stage breast cancer. Adjuvant chemotherapy might be given to those at high risk of recurrence. Recurrence is still possible after mastectomy and chemotherapy and most often occurs in the first two years. We aimed to determine the mechanisms in early local recurrence in both types. Methods: We used an observational method with a cross-sectional study design. The samples were patients with early-stage IDC and ILC, who underwent modified radical mastectomy (MRM) and got adjuvant chemotherapy with taxan and anthracycline base, and experienced recurrence in the first two years after surgery. The materials in this study were paraffin blocks from surgical specimens; we examined vimentin, α-SMA and MMP1, PDGF and CD95 by immunohistochemistry (IHC). Data analysis was done using OpenEpi 3.0.1 and EZR. We used pathway analysis with linear regression. Results: There were 25 samples with local recurrence and 25 samples without recurrence in the ductal type group. The lobular type group consisted of six subjects without recurrence and seven with recurrence. There were significant differences in the expression of vimentin (p=0.000 and 0.021, respectively), PDGF (p=0.000 and 0.002) and CD95 (p=0.000 and 0.045) in ductal and lobular cancer types, respectively. MMP1 (p=0.000) and α-SMA (p=0.000) only showed a significant difference in the ductal type. The pathway analysis showed that in the ductal type, the mechanism of recurrence was enabled by two factors: α-SMA and CD95. Meanwhile, for the lobular type, the recurrence mechanism was through the CD95 pathway. Conclusions: Local recurrence in early-stage IDC and ILC had different mechanisms.  These findings are expected to make cancer treatment in both types more focused and efficient.

Patient and illness factors influencing fear of recurrence in breast cancer women.

Objectives: To analyse the factors influencing the fear of recurrence in breast cancer, including age, spirituality, length of illness, stage of cancer and the cycles of chemotherapy. METHODS: The cross-sectional observational study was conducted from November 2021 to February 2022 at Dr Soepraoen Army Hospital and Baptis Hospital, East Java, Indonesia, and comprised breast cancer patients who had received at least one cycle of chemotherapy. Data was collected using the modified Spiritual Transcendence Scale questionnaire as well as from the patient's medical record. Data were analysed using univariate and linear regression. RESULTS: There were 135 subjects with a mean age of 47.14±6.36 years (range: 27-60 years). The largest group comprised patients with stage III disease 61(45.2%). Variables affecting the fear of recurrence was length of illness (p=0,007) and spirituality (p=0,001). CONCLUSIONS: Patients who had better spirituality value had lower fear of recurrence.

Hyperbaric oxygen therapy improves recovery at acute motor axonal neuropathy case.

Acute motor axonal neuropathy (AMAN) is a rare immune-mediated disorder characterized by acute flaccid paralysis with elevated levels of GM1 antibodies. It is also known as a subtype of the Guillain-Barre syndrome (GBS) and develops since antigen s serve as antibodies in the spinal cord. We report a case diagnosed as AMAN with symptoms of ascending limb symmetrical weakness. A neurological examination revealed a flaccid paralysis with multiple cranial nerve palsies. Electromyography showed an axonal type of GBS. The patient refused bone marrow fluid aspiration. Intravenous immunoglobulin was administered at the high care unit. Unfortunately, despite the standard therapy, an optimal recovery was not obtained. Hyperbaric oxygen (HBO) therapy has been known to be common in illnesses and some clinical diseases. Although it has not been indicated for peripheral neuropathy, a remarkable recovery was soon visible in the HBO-treated AMAN case. The HBO mechanisms involved here are anti-inflammation and immunomodulation.

Wistar Rats Hippocampal Neurons Response to Blood Low-Density Polyethylene Microplastics: A Pathway Analysis of SOD, CAT, MDA, 8-OHdG Expression in Hippocampal Neurons and Blood Serum Aß42 Levels.

Purpose: Low-density polyethylene microplastics are ingested into the bloodstream and distributed to all the organ tissue, including the hippocampus, causing toxic effects. This research aimed to elucidate the responses of hippocampal neurons to microplastic in the blood based on the expressions of superoxide dismutase (SOD), catalase (CAT) enzymes, malondialdehyde (MDA), 8-oxo-7,8-dihydro-2-deoxyguanosine (8-OHdG) in hippocampal neurons, and blood serum amyloid beta 1-42 (Aß42) levels using SMART PLS pathway analysis. Methods: This was a pure experimental research on Wistar rats with a post-test control group design. Five experimental groups (X1, X2, X3, X4, X5) were given 0.0375 mg, 0.075 mg, 0.15 mg, 0.3 mg, and 0.6 mg of low-density polyethylene microplastics mixed in 2cc distilled water, respectively. Furthermore, except for control (C), the groups received microplastics an oral probe for 90 days. Results: The molecular response of hippocampal neurons of Wistar rats to microplastics in the blood significantly decreased SOD enzyme expression, while CAT enzyme was unaffected. It considerably increased neuronal membrane damage (expression of MDA), increased considerably neuronal deoxyribonucleic acid damage (expression of 8-OHdG), and decreased blood serum Aß42 levels (pathway analysis, all t-value >1.96). Conclusion: The pathway analysis showed that hippocampal neurons were significantly affected by microplastic particles in the blood.

The Role of Human Neural Stem Cell Secretomes on the Repair of Spinal Cord Injury Post-laminectomy in Rattus norvegicus Through the Analysis of Basso-Beattie-Bresnahan Score Locomotors, Interleukin-10, Matrix Metalloproteinase 9, and Transforming Growth Factor-ß.

STUDY DESIGN: Experimental animal study. PURPOSE: This study aims to investigate the effects of treatment with human neural stem cell (HNSC) secretomes on subacute spinal cord injury (SCI) post-laminectomy by analyzing interleukin-10 (IL-10), matrix metalloproteinase 9 (MMP9), transforming growth factor-ß (TGF-ß), and Basso-Beattie-Bresnahan (BBB) score locomotors as expressions of neurological recovery. OVERVIEW OF LITERATURE: In the United States, SCI has a recovery rate of 0.08%, tetraplegia 58.7%, and paraplegia 40.6%. Therapeutic approaches to SCI have focused on modulating the secondary cascade to prevent neurological deterioration and glial scar formation. Increasing evidence has shown that the success of cell-based SCI therapy is attributed to the secretomes rather than the cells themselves, but the effect of treatment with HNSC secretomes in SCI is unclear. METHODS: This experimental study investigated 15 Rattus norvegicus rats that were divided into three groups: (1) normal, (2) SCI+nonsecretome, and (3) SCI+secretome (30 µL, intrathecal Th10). Model subacute SCI post-laminectomy was performed in 60 seconds using an aneurysm Yasargil clip with a closing forceps weighing 65 g (150 kdyn). At 35 days post-injury, the specimens were collected, and the immunohistochemicals of IL-10, MMP9, and TGF-ß were analyzed. Motor recovery was evaluated based on the BBB scores. RESULTS: The SCI post-laminectomy of rats treated with HNSC secretomes showed improvements in their locomotor recovery based on the BBB scores (p =0.000, mean=18.4) and decreased MMP9 (p =0.015) but had increased the levels of IL-10 (p =0.045) and TGF-ß (p =0.01). CONCLUSIONS: These results indicate that the factors associated with the HNSC secretomes can mitigate their pathophysiological processes of secondary damage after SCI and improve the locomotor functional outcomes in rats.

The mechanism of human neural stem cell secretomes improves neuropathic pain and locomotor function in spinal cord injury rat models: through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Background: Globally, spinal cord injury (SCI) results in a big burden, including 90% suffering permanent disability, and 60%-69% experiencing neuropathic pain. The main causes are oxidative stress, inflammation, and degeneration. The efficacy of the stem cell secretome is promising, but the role of human neural stem cell (HNSC)-secretome in neuropathic pain is unclear. This study evaluated how the mechanism of HNSC-secretome improves neuropathic pain and locomotor function in SCI rat models through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities. Methods: A proper experimental study investigated 15 Rattus norvegicus divided into normal, control, and treatment groups (30 µL HNSC-secretome, intrathecal in the level of T10, three days post-traumatic SCI). Twenty-eight days post-injury, specimens were collected, and matrix metalloproteinase (MMP)-9, F2-Isoprostanes, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß, and brain derived neurotrophic factor (BDNF) were analyzed. Locomotor recovery was evaluated via Basso, Beattie, and Bresnahan scores. Neuropathic pain was evaluated using the Rat Grimace Scale. Results: The HNSC-secretome could improve locomotor recovery and neuropathic pain, decrease F2-Isoprostane (antioxidant), decrease MMP-9 and TNF-α (anti-inflammatory), as well as modulate TGF-ß and BDNF (neurotrophic factor). Moreover, HNSC-secretomes maintain the extracellular matrix of SCI by reducing the matrix degradation effect of MMP-9 and increasing the collagen formation effect of TGF-ß as a resistor of glial scar formation. Conclusions: The present study demonstrated the mechanism of HNSC-secretome in improving neuropathic pain and locomotor function in SCI through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Perspective of Uncertainty and Emotional Responses in Breast Cancer Patients During the COVID-19 Pandemic.

Introduction: Breast cancer is a chronic disease that has implications for many aspects of the patient's life. Contracting the COVID-19 virus places cancer patients at a higher risk of infection. This condition triggers uncertainty which causes emotional responses. Objective: The aim of this study was to measure the relationship between the uncertainty perspective of breast cancer patients and emotional responses during the COVID-19 pandemic. Methods: This study used an observational study with a cross-sectional design. Data was collected from May to December 2021. The total sample of this study was 110 breast cancer patients undergoing chemotherapy at the Army Hospital of Dr. Soepraeon Malang, Indonesia. We used purposive sampling. The questionnaire used was a modified questionnaire from the Mishel Uncertainty in Illness Scale, a modified questionnaire from the Concerns about Recurrence Questionnaire, a modified questionnaire from the Zung Self Rating Anxiety Scale, and a modified questionnaire from the Depression, Anxiety, and Stress Scale. Data was analyzed using SPSS with a Spearman correlation test. Results: The mean uncertainty of the respondents was 75.98 or in the moderate category, emotional response was moderate fear with a mean score of 18.40, the average anxiety score was 41.05 or normal, and the mean depression score was 15.96 or low depression. In addition, there was a significant relationship between uncertainty and the emotional response among breast cancer patients in the era of the COVID-19 pandemic (p < .05). Conclusion: This study showed that there was a relationship between uncertainty and emotional response among breast cancer patients. It is important for nurses to provide good information about the disease among patients by using therapeutic communication and paying attention to the negative emotional responses of breast cancer patients.

The Effect of ACTH(4-10) PRO8-GLY9-PRO10 Administration on the Expression of IL-6 and IL-8 in Sprague Dawley Mice with Spinal Cord Injury.

Background Spinal cord injury (SCI) is a significant cause of morbidity since it results in the inflammation process which leads to necrosis or apoptosis. Inflammatory response to the tissue damage increases IL-6 and IL-8 levels. ACTH4 - 10Pro8-Gly9-Pro10 is a peptide community that has been shown to have a beneficial effect on minimizing the morbidity and increasing the recovery time. Methods This study is a true experimental laboratory research with a totally randomized method. The subjects were animal models with light and extreme compression of spinal cord, respectively. Results The administration of ACTH 4-10 in mild SCI in the 3-hour observation group did not show a significant difference in IL-6 expression compared with the 6-hour observation group. The administration of ACTH 4-10 in severe SCI showed a significantly lower expression level of IL-6 in the 3-hour observation group compared with the 6-hour one. The administration of ACTH 4-10 in severe SCI led to a significantly lower IL-8 expression in the 3-hour observation group compared with the 6-hour one. However, there was no significant difference in IL-8 expression in the group receiving ACTH 4-10 in 3 hours observation compared with that in 6 hours observation. Conclusion The administration of ACTH4-10Pro8-Gly9-Pro10 can reduce the expression of IL-6 and IL-8 at 3-hour and 6-hour observation after mild and severe SCI in animal models. Future research works are recommended.

Periosteum-induced ossification effect in skull defect through interleukin-8 and NF-κB pathway: An experimental study with Oryctolagus cuniculus rabbits.

Background: The purpose of this study was to analyze the response of inflammatory cytokines interleukin-8 (IL-8) and NF-κB to the closure of skull defect with periosteum as a scaffolding material in bone healing used after surgery. Methods: Thirty Oryctolagus cuniculus rabbits underwent a craniotomy to create a 20 mm diameter round defect in the parietal bones. The parietal bones were returned to its place and stabilized by an internal plate fixation. The defects were either left empty or implanted with periosteum. At 6 weeks, the specimens were euthanized and examined. Results: Histological examination showed a more well-developed formation of woven bone in the periosteum group. Immunohistochemical examinations showed that the use of periosteum in the closure of skull defects reduced the NF-κB and IL-8 response which affected the ossification process. Conclusion: The experiment showed that the use of periosteum was linked with IL-8 and NF-κB downregulation toward ossification effects at any point throughout the trial. Periosteum usage might be beneficial as a scaffolding material in bone healing for autograft cranioplasty in animal model and could be applied to clinical practice.

Antimicrobial activities of fungus comb extracts isolated from Indomalayan termite (Macrotermes gilvus Hagen) mound.

Incorporating antimicrobial components into food packaging materials can prevent microbial contamination. Fungus combs could be an alternative source of natural antimicrobial agents. In this study, n-hexane, ethyl acetate, methanol, and water extracts were obtained from fungus combs isolated from Indomalayan termite (Macrotermes gilvus Hagen) mound. Their antibacterial and antifungal activities against food spoilage microorganisms including Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Aspergillus flavus, and Aspergillus niger were evaluated by Kirby-Bauer disc diffusion and microdilution. Results showed that ethyl acetate extract formed the largest diameter inhibition zone for all tested bacteria and fungi, exhibited antibacterial activity against all tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.39 and 0.78 mg/mL, respectively, and suppressed A. flavus and A. niger with an MIC value of 0.78 mg/mL. This extract contained guaiacol and syringol, which were predicted as the main antimicrobial components in fungus comb. n-Hexane extract only inhibited Gram-positive bacteria. S. aureus ATCC 25923 was the most sensitive to all the extracts, and A. flavus was more sensitive than A. niger. All these fungus comb extracts exhibited antimicrobial activity against E. coli ATCC 25922, P. aeruginosa ATCC 27853, S. aureus ATCC 25923, A. flavus, and A. niger. This study revealed that fungus comb extracts, especially ethyl acetate, could be considered as a new antimicrobial agent.

Protective Effect of Hyperbaric Oxygen Treatment on Axon Degeneration after Acute Motor Axonal Neuropathy.

OBJECTIVES: Acute motor axonal neuropathy (AMAN) is a disease that leads to acute flaccid paralysis and may result from the binding of antibody and antigen to the spinal cord. The objective of this study is to evaluate the protective effect of hyperbaric oxygen treatment (HBOT) on axon degeneration of the spinal cord and sciatic nerve of the AMAN model rabbit. Axonal degeneration was assessed by evaluating glutathione (GSH) activity, interleukin-1ß (IL-1ß) expression, and clinical and histopathological features. METHODS: Twenty-one New Zealand rabbits were divided into three groups. The treatment group was exposed to 100% oxygen at 2.4 ATA 90 minutes for 10 days at a decompression rate of 2.9 pounds per square inch/minute. GSH level was evaluated using an enzyme-linked immune-sorbent assay. An expression of IL-1ß in the spinal cord was determined by immunohistochemistry. Clinical appearances were done by motor scale and body weight. Histological features observed neuronal swelling and inflammatory infiltration in the sagittal lumbar region and the undulation of the longitudinal sciatic nerve. RESULTS: Rabbits exposed to HBO had high GSH activity levels (p < 0.05) but unexpectedly had high IL1ß expression (p > 0.05). In addition, the HBO-exposed rabbits had a better degree of undulation, the size of neuronal swelling was smaller, the number of macrophages was higher, and motor function was better than the AMAN model rabbits (p < 0.05). CONCLUSIONS: These findings indicate that HBO therapy can decrease axon degeneration by triggering GSH activity, increasing IL-1ß level, and restoring tissues and motor status. In conclusion, HBO has a protective effect on axon degeneration of the spinal cord and sciatic nerve of the AMAN model rabbit.

Inhibition of Ras and STAT3 activity of 4-(tert-butyl)-N-carbamoylbenzamide as antiproliferative agent in HER2-expressing breast cancer cells.

OBJECTIVES: Human epidermal growth factor receptor type 2 (HER2)-expressing breast cancer patients indicate poor prognosis in disease progression. HER2 overexpression can increase activities of Ras-mitogen activated protein kinase (Ras-MAPK) pathway and Janus Kinase (JAK)-STAT3, increasing breast cancer cell proliferation as demonstrated by marker Ki67. Therapeutic options for HER2-expressing breast cancer are limited and have major side effects, so anticancer development as an antiproliferative is needed. From previous research, synthetic chemical 4-(tert-butyl)-N-carbamoylbenzamide (4TBCB) compound has cytotoxic activity in vitro on HER2-expressing breast cancer cells. This study wanted to determine the mechanism 4TBCB compound in inhibiting HER2 signaling through Rat Sarcoma (Ras) and signal transducer and activator of transcription 3 (STAT3) pathway in HER2-expressing breast cancer cells. METHODS: Breast cancer cells were isolated from the biopsy tissue of breast cancer patients. The isolated cells were cultured and given 4TBCB test compound with three concentrations (0.305, 0.61, and 1.22 mM) and lapatinib 0.05 mM as a comparison compound. Cancer cell cultures were stained with monoclonal antibodies phosphorylated HER2 (pHER2), phosphorylated Ras (pRas), phosphorylated STAT3 (pSTAT3), and Ki67. The expression of pHER2, pRas, pSTAT3, and Ki67 proteins was observed using the immunofluorescence method and the results were compared with control cells, namely cancer cells that were not given 4TBCB and lapatinib but stained with monoclonal antibodies. RESULTS: 4TBCB compounds (0.61 and 1.22 mM) and lapatinib can reduce pHER2, pRas, pSTAT3, and Ki67 expressions compared to control cells. CONCLUSIONS: 4TBCB compounds (0.61 and 1.22 mM) can reduce pHER2, pRas, pSTAT3, Ki67 expressions and predicted to inhibit HER2 signaling through the Ras and STAT3 pathways in HER2-expressing breast cancer cells.

Acute Motor Axonal Neuropathy Improvement 20 Days After Hyperbaric Oxygen Therapy.

We reported a rare case demonstrating that the hyperbaric oxygen chamber provided faster clinical improvement in a patient with a variant of Guillain-Barre Syndrome (GBS). A patient with progressive, acute weakness of upper extremity locomotor muscles and with difficulty breathing and swallowing was diagnosed with axonal GBS. Despite life-saving conventional therapies, there was no significant improvement until day 5. During hyperbaric oxygen therapy, there were daily gradual improvements until day 20, at which time the patient was capable of walking slowly without using a walking aid.

Inflammation in the lungs of mice due to methyl methacrylate exposure.

AIM: This study aimed to predict the potential inflammation in lungs caused by exposure to methyl methacrylate (MMA; in silico study) and assess inflammation in lungs in response to MMA inhalation in mice (in vivo study). MATERIALS AND METHODS: In silico and in vivo studies were performed using 24 mice divided into a control group (0 ppm MMA) and five treatment groups, which were exposed to 150 ppm MMA for 40, 80, 120, 160, and 200 min, respectively. Lung tissues were harvested and examined with a light microscope at 400×. RESULTS: In silico studies confirmed the existence of one activation bond between MMA and the toll-like receptor 4 (TLR-4), namely, His 228, with a MolDock score of -43.677 kcal/mol. Microscopic examination of lungs confirmed that a greater number of inflammatory cells were found in the treatment group than in the control group and symptoms of inflammation were clearly observable after 120 min of exposure. CONCLUSION: Thus, inflammation occurring due to MMA interaction with TLR-4 receptors can be predicted in silico and exposure to 150 ppm MMA for more than 120 min can cause lung inflammation in mice.

Inflammatory and Immunogenic Response of the Tissue after Application of Freeze-Dried Hydroxyapatite Gypsum Puger Scaffold Compared to Freeze-dried Hydroxyapatite Bovine Scaffold.

BACKGROUND: Inflammation is a mechanism or reaction of the natural immune system to defend from external hazards. All foreign objects that enter the body will trigger an immune response in the form of antibodies. In Indonesia, the prevalence of diseases that involve the inflammatory process in the body is high. Freeze-dried hydroxyapatite gypsum puger (HAGP) scaffold is a gypsum powder which is currently under development as a bone replacement material. Freeze-dried hydroxyapatite bovine (HAB) scaffold is a bone substitute material available on the market. OBJECTIVE: To analyze the inflammatory and immunogenic responses in the tissue after application of freeze-dried HAGP scaffold compared to freeze-dried HAB scaffold through mediators of tumor necrosis factor alpha (TNF-α) and immunoglobulin G (IgG) in rats. MATERIALS AND METHODS: This study used Wistar rats. HAGP group and HAB group were applied subcutaneously, settled for 7 and 14 days, then the levels of TNF-α and IgG were measured using enzyme-linked immunosorbent assay. Statistical analysis was done using nonparametric test with the Kruskal-Wallis test. RESULTS: TNF-α levels at day 7 in the HAGP group were nearly equal to the control group, while those in the HAB group were higher. Statistically, the significance was P = 0.184 (P > 0.05). At the 14th day, the level of IgG on the HAGP and HAB groups the level was higher than the control group, statistically it was found P= 0.127. CONCLUSION: freeze-dried HAGP scaffold compared to freeze-dried HAB scaffold did not cause inflammatory and immunogenic response on rats through mediators of TNF-α and IgG.

Mouse (Mus Musculus) Embryonic Cerebral Cortex Cell Death Caused by Carbofuran Insecticide Exposure.

INTRODUCTION: The aim of the study was to describe the process of neuron death in the cerebral cortex caused by embryonic carbofuran exposure. MATERIAL AND METHODS: 81 mouse foetuses from 27 breeding mice were used in the study. Carbofuran was administered by gavage from the 6th to the 15th day of gestation to two groups: one at 0.0208 and the other at 0.0417 mg/kg b.w. On the 17th day, the mice were sacrificed and the foetuses were taken to measure the ROS (malondialdehyde/MDA and superoxide dismutase/SOD) activity in brain tissue, the number of apoptotic embryonic cerebral cortex neurons using a TUNEL assay, and necrotic cells using HE staining. Examination of p53 and caspase 3 expression was done by immunohistochemistry. Data were analysed using analysis of variance (ANOVA) and Duncan's test. RESULTS: Increased activity of cerebral ROS characterised by significant elevation of the MDA level (P < 0.05), decreased SOD (P < 0.01), increased p53 and caspase 3 expression, and cerebral cortical neuron death either by necrosis or apoptosis (P < 0.05) were found. At the low dose carbofuran increased expression of p53, caspase 3, and apoptosis. At the high dose it increased levels of MDA and necrosis. CONCLUSION: Increased expression of p53 and caspase 3 and apoptosis indicated that carbofuran may cause apoptosis through the intrinsic pathway. The increased apoptosis grants an opportunity to prevent and treat the effect of ROS due to gestational carbofuran exposure.

High-Mobility Group Box 1 Expression in Mandibular Bone Cells of Experimental Periodontitis.

BACKGROUND: High-mobility group box 1 (HMGB1) was suggested to be associated with the pathogenesis of chronic periodontitis which characterized by alveolar bone loss. HMGB1 was defined as a bone-active cytokine, but the rule of HMGB1 in bone loss of chronic periodontitis is still understood. AIM: The aim of this study is to investigate the expression of HMGB1 on osteoblasts and osteoclasts in the mandible of chronic periodontitis. METHODS: This experimental study was conducted to rats injected by Porphyromonas gingivalis into the buccal and lingual subgingival area at a concentration of 2 × 109 CFU/mL three times a week with 2-day apart for 2, 3, 4, and 6 weeks as chronic periodontitis group and injected by normal saline as control group. Analysis of variance was used to examine the differences between groups followed by least significant difference post hoc test with the level of significance was <0.05. RESULTS: The HMGB1 expression was found in both osteoclasts and osteoblasts of mandibular bone by immunohistochemistry analysis. There was a difference of HMGB1 expression on osteoblasts and osteoclasts of chronic periodontitis. HMGB1 expression was found increased significantly in mandibular osteoblasts of chronic periodontitis, whereas the HMGB1 expression in mandibular osteoclast is higher in 2 and 3 weeks, but it was lower in 4 and 6 weeks. CONCLUSIONS: This study indicated a potential role for HMGB1 in bone loss of chronic periodontitis. HMGB1 on mandibular osteoclasts and osteoblasts may play different rules in the onset and progression of chronic periodontitis.