Post-injury Day Research Articles

Sciatic nerve stimulation alleviates acute neuropathic pain via modulation of neuroinflammation and descending pain inhibition in a rodent model

BackgroundNeuropathic pain (NP) is characterized by abnormal activation of pain conducting pathways and manifests as mechanical allodynia and thermal hypersensitivity. Peripheral nerve stimulation is used for treatment of medically refractory chronic NP and has been shown to reduce neuroinflammation. However, whether sciatic nerve stimulation (SNS) is of therapeutic benefit to NP remains unclear. Moreover, the optimal frequency for SNS is unknown. To address this research gap, we investigated the effect of SNS in an acute NP rodent model.MethodsRats with right L5 nerve root ligation (NRL) or Sham surgery were used. Ipsilateral SNS was performed at 2 Hz, 20 Hz, and 60 Hz frequencies. Behavioral tests were performed to assess pain and thermal hypersensitivity before and after NRL and SNS. Expression of inflammatory proteins in the L5 spinal cord and the immunohistochemical alterations of spinal cord astrocytes and microglia were examined on post-injury day 7 (PID7) following NRL and SNS. The involvement of the descending pain modulatory pathway was also investigated.ResultsFollowing NRL, the rats showed a decreased pain threshold and latency on the von Frey and Hargreaves tests. The immunofluorescence results indicated hyperactivation of superficial spinal cord dorsal horn (SCDH) neurons. Both 2-Hz and 20-Hz SNS alleviated pain behavior and hyperactivation of SCDH neurons. On PID7, NRL resulted in elevated expression of spinal cord inflammatory proteins including NF-κB, TNF-α, IL-1β, and IL-6, which was mitigated by 2-Hz and 20-Hz SNS. Furthermore, 2-Hz and 20-Hz SNS suppressed the activation of spinal cord astrocytes and microglia following NRL on PID7. Activity of the descending serotoninergic pain modulation pathway showed an increase early on PID1 following 2-Hz and 20-Hz SNS.ConclusionsOur results support that both 2-Hz and 20-Hz SNS can alleviate NP behaviors and hyperactivation of pain conducting pathways. We showed that SNS regulates neuroinflammation and reduces inflammatory protein expression, astrocytic gliosis, and microglia activation. During the early post-injury period, SNS also facilitates the descending pain modulatory pathway. Taken together, these findings support the therapeutic potential of SNS for acute NP.

Abstracts from The 39th Annual Symposium of the National Neurotrauma Society, including the AANS/CNS Joint Section on Neurotrauma and Critical Care

Abstracts from The 39^th Annual Symposium of the National Neurotrauma Society, including the AANS/CNS Joint Section on Neurotrauma and Critical Care

Clinical complications of surviving gunshot wounds to the head in children and adolescents: the Miami experience.

Gunshot wounds (GSWs) to the head in the pediatric population are both rare and devastating, with the clinical course of pediatric survivors poorly understood. Correspondingly, the aim of this study was to summarize the clinical complications clinicians can expect of survivors of GSW to the head in children and adolescents in hospital and after discharge. A retrospective review of our Level 1 trauma center database between 2011 and 2021 was performed. Clinical data was extracted for those patients aged ≤ 18years old who survived initial hospitalization with at least one documented follow-up. Categorical data were then compared using Chi-squared test. A total of 19 pediatric survivors of GSW to the head satisfied all selection criteria with an average age was 15.3years. The majority of cases were isolated head injuries (63%), with an average Glasgow Coma Score (GCS) of 11.9. Bullet trajectory was intraparenchymal in 11 (58%) cases and extraparenchymal in 8 (42%) cases, with 15 (79%) patients treated by surgical intervention. A total of 13 (68%) patients experienced a complication during their hospitalization, with the most common being sympathetic hypertension and endocrinologic salt wasting, each occurring in 5 (26%) patients. With respect to complication categories, the intraparenchymal patients experienced statistically more complications than extraparenchymal patients that were infectious (54% vs 0%, P = 0.01) and sympathetic (45% vs 0%, P = 0.03) in nature. However, with respect to overall neurologic (P = 0.24), endocrinologic (P = 0.24), and traumatic (P = 0.24) complications, their incidences were statistically comparable. All patients were successfully discharged on average post-injury day 22 with an average GCS of 14.0. Mean follow-up for the cohort was 42.6months, with an average GCS of 14.3. A total of 6 (32%) patients experienced a complication relatable to their initial GSW injury after discharge. The most common individual complication was new-onset seizures in 3 (16%) patients. Survivors of pediatric GSW to the head can experience multi-systemic complications during both initial hospitalization and afterwards, and bullet trajectory involving the parenchyma may be associated with specific complications more than others. Dedicated inpatient management and outpatient follow-up involving surveillance for complications across all systems, not just neurological, are recommended to ensure patients receive the best care possible.

Role and mechanism of Vγ4 T cells in impaired wound healing of rapamycin-induced full-thickness skin defects in mice

Role and mechanism of Vγ4 T cells in impaired wound healing of rapamycin-induced full-thickness skin defects in mice

Effects of exosomes from human adipose-derived mesenchymal stem cells on inflammatory response of mouse RAW264.7 cells and wound healing of full-thickness skin defects in mice

Effects of exosomes from human adipose-derived mesenchymal stem cells on inflammatory response of mouse RAW264.7 cells and wound healing of full-thickness skin defects in mice

482 Traumatic Brain Injury and Hemorrhage in a Juvenile Rat Model of Polytrauma Leads to Immunosuppression and Splenic Alterations

INTRODUCTION: Traumatic brain injury (TBI) is a common cause of morbidity and mortality for which there are no pharmacotherapeutic agents. We have previously shown, with clinical data and in an animal model, that TBI with a concurrent extra-cranial injury can reliably lead to post-injury immunosuppression. METHODS: To assess the clinical relevance of our combined model, we examined lungs for evidence of spontaneous bacterial colonization. Prepubescent (28 day old) rats were injured with a moderately severe controlled cortical impact model and then had 25% blood volume removed by arteriotomy. Blood and spleen samples at post-injury day 1 were incubated with T or B cell immunostimulant and were examined for IFN-G production using an Eli-Spot assay. Spleen samples were examined at this timepoint for apoptosis using Annexin V staining. Lungs were also harvested and plated on blood agar to examine spontaneous bacterial colonization. RESULTS: Stimulation of whole blood samples and spleen with PMA at post-injury day 1 were associated with significant decreases in IFN-G-positive cells/million, as compared with samples from sham animals. As compared to sham, spleen samples from injured animals showed a marked increase in splenocyte apoptosis in the white pulp of the spleen. Lung samples, plated on blood agar, showed a 300% increase in colonies per plate in injured animals. CONCLUSION: These data add to a growing body of literature suggesting that severe trauma can lead to immunosuppression. Our findings further suggest a potential role for the spleen in altering leukocyte function following injury.

Posttraumatic pneumonectomy and management of severely contaminated pleural space.

Posttraumatic pneumonectomy and management of severely contaminated pleural space.

Glutamine supplementation improves contractile function of regenerating soleus muscles from rats.

This study evaluated the effects of glutamine supplementation immediately after freezing injury on morphological and contractile function of regenerating soleus muscles from rats. Young male Wistar rats were subjected to cryolesion of soleus muscles, and immediately after received a daily supplementation of glutamine (1g/kg/day). The muscles were evaluated on post-injury days 3 and 10. Glutamine-supplemented injured muscles had a lower number of CD11b positive immune cells and higher mRNA levels of IL-4 compared to those from the cryolesioned muscles analyzed on post-injury day 3. The mRNA and protein expression levels of the myogenic transcription factor MyoD were also higher in glutamine-supplemented injured muscles than in injured muscles examined on post-cryolesion day 3. In addition, glutamine-supplemented injured muscles had a higher size of their regenerating myofibers, attenuated decline in maximum tetanic strength and improved fatigue resistance compared to those from injured muscles evaluated on post-cryolesion day 10. No effect was observed in uninjured muscles supplemented with glutamine. Our results suggest that glutamine supplementation improves the resolution of inflammation, as well as the size and functional recovery of regenerating myofibers from soleus muscles by accelerating the up-regulation of IL-4 and MyoD expression. Future non-pharmacological rehabilitation studies are warranted to investigate the effect of glutamine supplementation on the outcome of injured skeletal muscles.

Effects of porcine acellular dermal matrix combined with human epidermal stem cells on wound healing of full-thickness skin defect in nude mice

Effects of porcine acellular dermal matrix combined with human epidermal stem cells on wound healing of full-thickness skin defect in nude mice

Comparative study of role of physiotherapy alone versus physiotherapy combined with yoga in rehabilitation after a sports injury. What can a primary physician offer?

Posttraumatic rehabilitation of sports injuries involves physiotherapy. Additionally, nonsurgical treatment of sports injuries involves regular physiotherapy as a major treatment therapy. This study aimed to evaluate the effects of yoga in addition to regular physiotherapy on these patients. In the present comparative study, we evaluated the effects of regular physiotherapy alone versus physiotherapy combined with yoga on 212 patients following various knee injuries treated nonsurgically. The study was conducted after obtaining hospital ethical, committee clearance, and written informed consent from patients. The patients were assigned into two groups: group C (Conventional) and group Y (Yoga group). The patients in the regular group received physiotherapy rehabilitation program, whereas the yoga group received additional yoga once every day by a yoga expert during their hospital stay. We provided written guidelines and photographs of the yoga asanas and instructed to perform them 3 days/week once they were home. The data on WOMAC score were collected at 6 weeks, 3 months, and at 6 months from the day of discharge from the hospital. We noted that the yoga group patients showed a significant improvement (P < 0.05) in all modalities like pain, stiffness, and function subscales of the WOMAC scale. They experienced significant reduction in pain and stiffness compared with the regular or conventional group on the seventh postinjury day, 6 weeks, 3 months, and 6 months after the initial injury. In this study, a combination of regular physiotherapy and yoga provided better functional outcomes than physiotherapy alone.

Anti-inflammatory and Antioxidant Effects of Japanese Herbal Medicine Kyoseihatekigan on Vocal Fold Wound Healing

The Japanese herbal medicine kyoseihatekigan (KHG) has been used to alleviate the symptoms of croaky voice and globus hystericus, and each of its components has anti-inflammatory and antioxidant effects. However, the mechanisms underlying these beneficial actions of KHG on the vocal folds remain largely unknown. We examined the effects of KHG on rat vocal fold wound healing and assessed its anti-inflammatory and antioxidant properties. Animal model. The vocal folds of Sprague-Dawley rats were unilaterally injured under endoscopy. Rats were divided into three groups based on KHG dosing from pre injury day 4 to post injury day 3: 0 mg/kg/day (sham group), 500 mg/kg/day (1% KHG group) and 1000 mg/kg/day (2% KHG group). Histologic changes were examined to assess the degree of inflammation and oxidative stress at day 3, and fibrosis at day 56. In addition, gene expression related to pro-inflammatory cytokines and transforming growth factor-beta1 (TGF-β1) signaling was examined by quantitative real-time polymerase chain reaction (qPCR). Histologic analysis showed that the 1% and 2% KHG treatments significantly decreased cell infiltration and the 4-hydroxy-2-nonenalx-immunopositive area, and increased hyaluronic acid at day 3. Both KHG treatments significantly decreased fibrosis at day 56. qPCR revealed that mRNA of interleukin-1β and cyclooxygenase-2 were significantly suppressed at day 1 and TGF-β1 mRNA was significantly downregulated at day 5 in both KHG groups. The current findings suggest that KHG has anti-inflammatory and antioxidant effects in the early phase of vocal fold wound healing, which can lead to better wound healing with less scar formation.

Preparation and roles of sliver-loaded viscous hydrogel in healing of full-thickness skin defect wounds with bacterial colonization in mice

Preparation and roles of sliver-loaded viscous hydrogel in healing of full-thickness skin defect wounds with bacterial colonization in mice

Effects of reactive oxygen species-responsive antibacterial microneedles on the full-thickness skin defect wounds with bacterial colonization in diabetic mice

Effects of reactive oxygen species-responsive antibacterial microneedles on the full-thickness skin defect wounds with bacterial colonization in diabetic mice

Surgical Site Infection after Surgical Stabilization of Rib Fractures: Rare but Morbid.

Background: Although surgical stabilization for rib fractures (SSRF) has been adopted widely over the past decade, little information is available regarding the prevalence and outcomes of post-operative surgical site infection (SSI). We hypothesized that SSI after SSRF is uncommon but morbid. Patients and Methods: Patients undergoing SSRF at a level 1 trauma center from 2010-2020 were reviewed. The primary outcome was the prevalence of SSI, documented by clinical examination, radiography, systemic markers of infection, and microbiology. Results: Of 228 patients undergoing SSRF, 167 (73.2%) were male, the median age was 53 years (P25-P75; 41-63 years), injury severity score (ISS) was 19 (P25-P75, 13-26), with a median of eight fractured ribs (P25-P75, 6-11). All stabilization plates were titanium. SSRF was typically performed on post-injury day one (P25-P75, 0-2 days) after trauma. All patients received antibiotic agents within 30 minutes of incision, and a median of four ribs (P25-P75, 3-6) were repaired. Four (1.8%) patients developed an SSI and all underwent implant removal. Two patients required implant removal within 30 days (on post-operative day seven and 17) and two for chronic infection at seven and 17 months after SSRF. The causative organism was methicillin-sensitive Staphylococcus aureus (MSSA) bacteria in all patients. After implant removal, three patients received intravenous and oral antibiotic agents, ranging from two to six weeks, without recurrent infection. No patient required additional SSRF. Conclusions: Surgical site infection after SSRF is rare but morbid and can become symptomatic within one week to 17 months. Implant removal results in complete recovery.

Automatic Detection of EEG Epileptiform Abnormalities in Traumatic Brain Injury using Deep Learning.

Traumatic brain injury (TBI) is a sudden injury that causes damage to the brain. TBI can have wide-ranging physical, psychological, and cognitive effects. TBI outcomes include acute injuries, such as contusion or hematoma, as well as chronic sequelae that emerge days to years later, including cognitive decline and seizures. Some TBI patients develop posttraumatic epilepsy (PTE), or recurrent and unprovoked seizures following TBI. In recent years, significant efforts have been made to identify biomarkers of epileptogenesis, the process by which a normal brain becomes capable of generating seizures. These biomarkers would allow for a higher standard of care by identifying patients at risk of developing PTE as candidates for antiepileptogenic interventions. In this paper, we use deep neural network architectures to automatically detect potential biomarkers of PTE from electroencephalogram (EEG) data collected between post-injury day 1-7 from patients with moderate-to-severe TBI. Continuous EEG is often part of multimodal monitoring for TBI patients in intensive care units. Clinicians review EEG to identify the presence of epileptiform abnormalities (EAs), such as seizures, periodic discharges, and abnormal rhythmic delta activity, which are potential biomarkers of epileptogenesis. We show that a recurrent neural network trained with continuous EEG data can be used to identify EAs with the highest accuracy of 80.78%, paving the way for robust, automated detection of epileptiform activity in TBI patients.

Interleukin-22 mitigates acute respiratory distress syndrome (ARDS).

BackgroundThe goal of this study was to determine if IL-22:Fc would Acute Respiratory Distress Syndrome (ARDS).Summary background dataNo therapies exist for ARDS and treatment is purely supportive. Interleukin-22 (IL-22) plays an integral component in recovery of the lung from infection. IL-22:Fc is a recombinant protein with a human FC immunoglobulin that increases the half-life of IL-22.Study designARDS was induced in C57BL/6 mice with intra-tracheal lipopolysaccharide (LPS) at a dose of 33.3 or 100 ug. In the low-dose LPS group (LDG), IL-22:FC was administered via tail vein injection at 30 minutes (n = 9) and compared to sham (n = 9). In the high-dose LPS group (HDG), IL-22:FC was administered (n = 11) then compared to sham (n = 8). Euthanasia occurred after bronchioalveolar lavage (BAL) on post-injury day 4.ResultsIn the LDG, IL-22:FC resulted in decreased protein leak (0.15 vs. 0.25 ug/uL, p = 0.02). BAL protein in animals receiving IL-22:Fc in the HDG was not different. For the HDG, animals receiving IL-22:Fc had lower BAL cell counts (539,636 vs 3,147,556 cells/uL, p = 0.02). For the HDG, IL-6 (110.6 vs. 527.1 pg/mL, p = 0.04), TNF-α (5.87 vs. 25.41 pg/mL, p = 0.04), and G-CSF (95.14 vs. 659.6, p = 0.01) levels were lower in the BAL fluid of IL-22:Fc treated animals compared to sham.ConclusionsIL-22:Fc decreases lung inflammation and lung capillary leak in ARDS. IL-22:Fc may be a novel therapy for ARDS.

Traumatic brain injury and hemorrhage in a juvenile rat model of polytrauma leads to immunosuppression and splenic alterations

BackgroundTraumatic brain injury (TBI) is a common cause of morbidity and mortality. We have previously shown that TBI with a concurrent extra-cranial injury reliably leads to post-injury suppression of the innate immune system, but the impact of this injury on the adaptive immune system is unknown. We present data showing that combined injury reduced immune response as assayed in both blood and spleen samples and that these changes parallel apoptosis in the spleen. To assess the clinical relevance of these changes, we examined lungs for spontaneous bacterial colonization. MethodsFor these studies, prepubescent (28 day old) rats were injured using a controlled cortical impact model and then 25% blood volume removal by arteriotomy, and injured animals were compared with sham injured animals. Blood and spleen samples at post-injury day 1 were incubated with or without immunostimulant and examined for IFN-γ production using an Eli-Spot assay. Spleen samples were also examined for apoptosis using Annexin V staining, and lungs were harvested and plated on blood agar to examine for spontaneous bacterial colonization. ResultsStimulations of whole blood and spleen samples with phorbol 12-myristate 13-acetate/ionomycin (PMA/I) at post-injury day 1 were associated with significant decreases in IFN-γ-positive cells/million in injured animals. Stimulation of whole blood with either PMA/I or pokeweed mitogen led to reduced tumor necrosis factor alpha production. Spleen from injured animals showed a marked increase in apoptosis. Lung samples showed a 300% increase in colonies per plate in injured animals. ConclusionsThese data suggest that the combined injury can lead to adaptive immunosuppression, and our findings further suggest a potential role for the spleen in altering leukocyte function following injury.

Effects and mechanism of hepatocyte growth factor-modified human adipose mesenchymal stem cells on wound healing of full-thickness skin defects in diabetic rats

Objective: To investigate the effects and mechanism of hepatocyte growth factor (HGF)-modified human adipose mesenchymal stem cells (ADSCs) on the wound healing of full-thickness skin defects in diabetic rats. Methods: The experimental research method was adopted. The discarded abdominal adipose tissue was collected from a 35-year-old healthy female who underwent abdominal liposuction in the Department of Plastic Surgery of the First Affiliated Hospital of Air Force Medical University in December 2019. The long spindle-shaped primary ADSCs were obtained by collagenase digestion, and the third passage of cells were identified by flow cytometry to positively express ADSCs surface markers CD29 and CD90 and negatively express CD34 and CD45. The third passage of ADSCs were used for the subsequent experiments. ADSCs were transfected with lentivirus-mediated HGF for 4 h (obtaining HGF modified ADSCs) and then routinely cultured for 24 h. The cell morphology was observed under an inverted phase contrast microscope, and the transfection rate was calculated. Eighty-one male Sprague-Dawley rats aged 4 weeks were induced into diabetic rat model by high glucose and high fat diet combined with streptozotocin injection. A full-thickness skin defect wound of 1.5 cm×1.5 cm was made on the back of each rat. The injured rats were divided into phosphate buffer solution (PBS) group, ADSCs alone group, and HGF-modified ADSCs group according to the random number table, with 27 rats in each group. The rats were injected with the same volume of corresponding substances around the wound on post injury day (PID) 1, 3, and 7, respectively. Nine rats in each group were selected according to the random number table, the wound area of whom was measured on PID 0 (immediately), 3, 7, 10, and 14 (after injection on injection day), and the wound healing rates on PID 3, 7, 10, and 14 were calculated. Nine remaining rats in each group were sacrificed after injection on PID 3 and 7, respectively, and the skin tissue around the wound were collected. The mRNA expressions of inflammatory factors such as tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-10 on PID 3 and collagen type Ⅰ and Ⅲ on PID 7 were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. The expression level of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay on PID 7. The protein expression of nuclear factor κb-p65 on PID 3 and phosphorylation level of protein kinase B (Akt) on PID 7 were detected by Western blotting. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, least significant difference t test, and Bonferroni correction. Results: After 24 h of culture, the HGF-transfected human ADSCs showed good morphology, which was not different with the non-transfected ADSCs, and the transfection rate reached 90%. On PID 3, 7, 10, and 14, the wound healing rates of rats in HGF-modified ADSCs group were (31.5±1.0)%, (75.2±2.0)%, (92.2±1.3)%, and (99.1±1.8)%, respectively, being significantly higher than (21.4±1.3)%, (61.4±1.5)%, (80.1±2.1)%, and (92.4±1.8)% in PBS group and (25.1±2.1)%, (67.2±1.3)%, (89.3±1.4)%, and (95.1±2.1)% in ADSCs alone group (t=1.452, 0.393, 0.436, 0.211, 4.982, 3.011, 4.211, 7.503, P<0.05 or P<0.01). On PID 3, compared with those in PBS group and ADSCs alone group, the mRNA expressions of TNF-α and IL-1β and protein expression of nuclear factor κb-p65 in the skin tissue around the wound of rats in HGF-modified ADSCs group were significantly decreased (t=7.281, 17.700, 9.447, 6.231, 13.083, 7.783, P<0.01), and the mRNA expression of IL-10 in the skin tissue around the wound of rats in HGF-modified ADSCs group was significantly increased (t=-6.644, -6.381, P<0.01). On PID 7, compared with those in PBS group and ADSCs alone group, the mRNA expressions of collagen type Ⅰ and Ⅲ, the expression level of VEGF, and the phosphorylation level of Akt in the skin tissue around the wound of rats in HGF-modified ADSCs group were significantly increased (t=-5.126, -4.347, -5.058, -3.367, -10.694, -19.876, -4.890, -6.819, P<0.05 or P<0.01). Conclusions: HGF-modified human ADSCs can significantly promote the wound healing of full-thickness skin defects in diabetic rats. The mechanism may be related to the inhibition of TNF-α and IL-1β expression, the promotion of IL-10, collagen type Ⅰ and Ⅲ, and VEGF expression, which could be related to the inhibition of nuclear factor κB signaling pathway, and the promotion of Akt signaling pathway.

Study on the effect and mechanism of recombinant human intestinal trefoil factor on intestinal mucosal injury and repair in burned mice

Study on the effect and mechanism of recombinant human intestinal trefoil factor on intestinal mucosal injury and repair in burned mice

Changes in the related indicators of bone formation and bone resorption in severely burned rats

Objective: To observe the changes in the related indicators of bone formation and bone resorption in severely burned rats. Methods: The experimental research method was adopted. Thirty female Sprague-Dawley rats aged 6 to 8 weeks were divided into sham injury group, 12% total body surface area (TBSA) full-thickness burn group, and 24%TBSA full-thickness burn group according to the random number table, with 10 rats in each group. The rats were treated on the back correspondingly, after which, the burned rats were rehydrated by intraperitoneal injection according to the Parkland formula, and the wound was coated with 20 g/L iodophor until wound healing. On post injury day (PID) 28, the tibia tissue of rats in each group was collected. The new bone tissue and the number of osteoclasts were observed after staining with Masson and tartrate-resistant acid phosphatase, respectively. The abdominal aortic blood of rats in each group was harvested for serum preparation. The bone metabolism indexes of serum calcium ion and phosphorus ion concentration were determined by the methyl thymol blue colorimetric method and phosphomolybdic acid method, respectively. The serum levels of bone formation marker of aminoterminal propeptide of type 1 procollagen (P1NP) and bone resorption marker of beta-carboxy-terminated peptide of type Ⅰ collagen (β-CTX) were determined by enzyme-linked immunosorbent assay. The first lumbar spine tissue of rats in each group was collected, and the mRNA expression levels of osteoprotegerin, receptor activator of nuclear factor-κB ligand (RANKL), tumor necrosis factor receptor-associated factor 6 (TRAF-6), nuclear factor of activated T cell 1 (NFATC1), c-Fos, and c-Src were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. Data were statistically analyzed with one-way analysis of variance, Bonferroni method, Welch test, Games-Howell test, Kruskal-Wallis test, Mann-Whitney U test, and Bonferroni correction. Results: On PID 28, compared with that in sham injury group, the formation of new bone tissue in the tibia tissue of rats in the two burn groups was decreased, and the larger the burn area, the more obvious the decrease. The numbers of osteoclasts in the tibia tissue of rats in the two burn groups were similar, both significantly more than the number in sham injury group. On PID 28, the serum calcium ion concentration and serum level of β-CTX of rats in the three groups were similar (P>0.05). The serum phosphorus ion concentration of rats in 24%TBSA full-thickness burn group was significantly higher than that in 12%TBSA full-thickness burn group (P<0.05), and the serum phosphorus ion concentrations in the two burn groups were significantly higher than the concentration in sham injury group (P<0.01). The serum level of P1NP of rats in 24%TBSA full-thickness burn group was significantly lower than that in sham injury group (P<0.01). On PID 28, the mRNA expression levels of osteoprotegerin in the first lumbar spine tissue of rats in sham injury group, 12%TBSA full-thickness burn group, and 24%TBSA full-thickness burn group were 1.01±0.20, 1.71±0.83, and 2.24±0.51, respectively, and that in 24%TBSA full-thickness burn group was significantly higher than that in sham injury group (P<0.01). The mRNA expression level of RANKL in the first lumbar spine tissue of rats in 24%TBSA full-thickness burn group was 1.31±0.17, which was significantly higher than 1.00±0.14 in sham injury group and 0.97±0.10 in 12%TBSA full-thickness burn group (P<0.01). The mRNA expression levels of TRAF-6, NFATC1 (Z=3.141, 3.782), and c-Src in the first lumbar tissue of rats in 12%TBSA full-thickness burn group and 24%TBSA full-thickness burn group and the mRNA expression level of c-Fos in the first lumbar tissue of rats in 12%TBSA full-thickness burn group were significantly higher than those in sham injury group (P<0.05 or P<0.01). The mRNA expression levels of c-Fos and c-Src in the first lumbar spine tissue of rats in 12%TBSA full-thickness burn group were significantly higher than those in 24%TBSA full-thickness burn group (P<0.01). Conclusions: Severe burns can cause a decrease in the generation of new bone tissue, an increase in the number of osteoclasts and the serum phosphorus ion concentration, and a decrease in the serum level of P1NP in rats. The level of osteoprotegerin, RANKL, TRAF-6, NFATC1, c-Fos, and c-Src in bone tissue showed an increasing trend while the level of NFATC1, c-Fos, and c-Src showed a decreasing trend with the increase of burn area.