Radiation-induced SOD2 overexpression sensitizes colorectal cancer to radiation while protecting normal tissue

Iron Supplementation Increases Tumor Burden and Alters Protein Expression in a Mouse Model of Human Intestinal Cancer

Iron supplements are widely consumed. However, excess iron may accelerate intestinal tumorigenesis. To determine the effect of excess iron on intestinal tumor burden and protein expression changes between tumor and normal tissues, ApcMin/+ mice were fed control (adequate) and excess iron (45 and 450 mg iron/kg diet, respectively; n = 9/group) for 10 wk. Tumor burden was measured, and two-dimensional fluorescence difference gel electrophoresis was used to identify differentially expressed proteins in tumor and normal intestinal tissues. There was a significant increase (78.3%; p ≤ 0.05) in intestinal tumor burden (mm2/cm) with excess iron at wk 10. Of 980 analyzed protein spots, 69 differentially expressed (p ≤ 0.05) protein isoforms were identified, representing 55 genes. Of the isoforms, 56 differed (p ≤ 0.05) between tumor vs. normal tissues from the adequate iron group and 23 differed (p ≤ 0.05) between tumors from the adequate vs. excess iron. Differentially expressed proteins include those involved in cell integrity and adaptive response to reactive oxygen species (including, by gene ID: ANPEP, DPP7, ITGB1, PSMA1 HSPA5). Biochemical pathway analysis found that iron supplementation modulated four highly significant (p ≤ 0.05) functional networks. These findings enhance our understanding of interplay between dietary iron and intestinal tumorigenesis and may help develop more specific dietary guidelines regarding trace element intake.

Radioprotective countermeasures for radiation injury (Review)

A series of physiological and pathological changes occur after radiotherapy and accidental exposure to ionizing radiation (IR). These changes cause serious damage to human tissues and can lead to death. Radioprotective countermeasures are radioprotective agents that prevent and reduce IR injury or have therapeutic effects. Based on a good understanding of radiobiology, a number of protective agents have achieved positive results in early clinical trials. The present review grouped known radioprotective agents according to biochemical categories and potential clinical use, and reviewed radiation countermeasures, i.e., radioprotectors, radiation mitigators and radiotherapeutic agents, with an emphasis on their current status and research progress. The aim of the present review is to facilitate the selection and application of suitable radioprotectors for clinicians and researchers, to prevent or reduce IR injury.

Effects of Antioxidant Gene Overexpression on Stress Resistance and Malignization In Vitro and In Vivo: A Review

Reactive oxygen species (ROS) are normal products of a number of biochemical reactions and are important signaling molecules. However, at the same time, they are toxic to cells and have to be strictly regulated by their antioxidant systems. The etiology and pathogenesis of many diseases are associated with increased ROS levels, and many external stress factors directly or indirectly cause oxidative stress in cells. Within this context, the overexpression of genes encoding the proteins in antioxidant systems seems to have become a viable approach to decrease the oxidative stress caused by pathological conditions and to increase cellular stress resistance. However, such manipulations unavoidably lead to side effects, the most dangerous of which is an increased probability of healthy tissue malignization or increased tumor aggression. The aims of the present review were to collect and systematize the results of studies devoted to the effects resulting from the overexpression of antioxidant system genes on stress resistance and carcinogenesis in vitro and in vivo. In most cases, the overexpression of these genes was shown to increase cell and organism resistances to factors that induce oxidative and genotoxic stress but to also have different effects on cancer initiation and promotion. The last fact greatly limits perspectives of such manipulations in practice. The overexpression of GPX3 and SOD3 encoding secreted proteins seems to be the "safest" among the genes that can increase cell resistance to oxidative stress. High efficiency and safety potential can also be found for SOD2 overexpression in combinations with GPX1 or CAT and for similar combinations that lead to no significant changes in H₂O₂ levels. Accumulation, systematization, and the integral analysis of data on antioxidant gene overexpression effects can help to develop approaches for practical uses in biomedical and agricultural areas. Additionally, a number of factors such as genetic and functional context, cell and tissue type, differences in the function of transcripts of one and the same gene, regulatory interactions, and additional functions should be taken into account.

Extracellular vesicles-derived microRNAs expression as biomarkers for neurological radiation injury: Risk assessment for space exploration

Space missions pose threats to the health of the astronauts due to long-term exposure to galactic cosmic rays and solar particle events comprised predominantly of medium to high energy protons, energetic helium ions, and energetic high atomic number particles (HZEs). While the tissue-specific effects of radiation have been studied extensively, the changes in exosomal miRNA expression levels in response to acute radiation exposure have not been assessed. Extracellular vesicles (EVs) originate from the host cells and contain nucleic acid and proteins that can modify the physiology of the receiving cells via the transfer of genomic, proteomic, and lipids cargo. Detection and analysis of miRNA cargo of circulating EVs is an emerging method for non-invasive diagnosis and monitoring of neurological disorders. This study characterizes the EV-derived miRNA expression profiles of human astrocytes to identify those that are altered after treatment with 3 Gy proton radiation as biomarkers of neurological radiation injury. The relationship between radiation and miRNA extracellular vesicles expression levels was investigated in human astrocytes after treatment with 3 Gy proton radiation at Willis-Knighton Cancer Center. Microarray analysis was performed using miRNA from the EVs enriched fraction in the cell culture medium collected from sham-control and radiation-treated cells. The exosomal levels of 13 miRNAs were significantly (FDR p < 0.05) down-regulated after exposure to high-energy radiation. The computational analysis identified hsa-miR-762, hsa-let-7c-5p, and has-let-7b-5p regulate the highest number of genes being associated with cognitive, mental, and motor delay. These miRNAs target the same subset of genes (Amd1, CCNF, COX6B, PLXND1) that are associated with epileptic encephalopathy; frontotemporal dementia; mitochondrial complex iv deficiency, and a rare neurological condition (Moebius syndrome) respectively. GO enrichment analysis of the biological processes identified overrepresentation in mRNA polyadenylation and regulation of glutamine and long fatty acids transport. Gene expression analysis confirmed the upregulation of the glutamine synthetase after irradiation. Significant fold enrichment of GO l-glutamine transmembrane transporter activity was identified in the molecular function category as well indicating exosome-mediated regulation of this important pathway after proton radiation exposure.

Does Gender Difference Effect Radiation-Induced Lung Toxicity? An Experimental Study by Genetic and Histopathological Predictors

Several studies have reported differences in radiation toxicity between the sexes, but these differences have not been tested with respect to histopathology and genes. This animal study aimed to show an association between histopathological findings of radiation-induced lung toxicity and the genes ATM, SOD2, TGF-β1, XRCC1, XRCC3 and HHR2. In all, 120 animals were randomly divided into 2 control groups (male and female) and experimental groups comprising fifteen rats stratified by sex, radiotherapy (0 Gy vs. 10 Gy), and time to sacrifice (6, 12, and 24 weeks postirradiation). Histopathological evaluations for lung injury, namely, intra-alveolar edema, alveolar neutrophils, intra-alveolar erythrocytes, activated macrophages, intra-alveolar fibrosis, hyaline arteriosclerosis, and collapse were performed under a light microscope using a grid system; the evaluations were semi quantitatively scored. Then, the alveolar wall thickness was measured. Real-time quantitative reverse transcription PCR (RT-qPCR) was used to determine gene expression differences in ATM, TGF-β1, XRCC1, XRCC3, SOD2 and HHR2L among the groups. Histopathological data showed that radiation-induced acute, subacute, and chronic lung toxicity were worse in male rats. The expression levels of the evaluated genes were significantly higher in females than males in the control group, but this difference was lost over time after radiotherapy. Less toxicity in females may be attributable to the fact that the expression of the evaluated genes was higher in normal lung tissue in females than in males and the changes in gene expression patterns in the postradiotherapy period played a protective role in females. Additional data related to pulmonary function, lung weights, imaging, or outcomes are needed to support this data that is based on histopathology alone.

Radio-sensitivity enhancement in HT29 cells through magnetic hyperthermia in combination with targeted nano-carrier of 5-Flourouracil

Normal tissue complication and development of radioresistance in cancer cells are known as the main challenges of ionizing radiation treatment. In the current study, we intended to induce selective radiosensitization in HT29 cancer cells by developing folic acid modified magnetic triblock copolymer nanoparticles as carrier of 5-Flourouracil (5-FU) which was further used in combination with hyperthermia. The aforementioned nanoparticles were synthesized and characterized by differential scanning calorimetric analysis (DSC), UV-visible spectroscopy, dynamic light scattering (DLS), zeta sizer, and transmission electron microscopy (TEM). These nanoparticles were also assessed to determine drug loading capacity (DLC %) and drug release profile. The cytotoxicity of nanoparticles was evaluated on two different cell lines: HUVEC and HT29. Furthermore, radiosensitivity induction of the nanoparticles with and without exposure of alternative magnetic field was investigated. MTT-based cytotoxicity assay demonstrated that the therapeutic ratio was enhanced in response to using 5-FU-loaded nanoparticles as compared to 5-FU. Various characterizations including gene expression study, measurement of reactive oxygen species (ROS) generation, Annexin V/PI staining, and clonogenic assay revealed that ionizing radiation in combination with hyperthermia in the presence of the synthesized nanoparticles led to maximal anti-cancer effects as compared to other single (P < 0.001) and combined treatments (P < 0.01). Our results suggested that combined treatment based on using folic acid modified magnetic copolymer nanoparticle as carrier of 5-FU accompanied with hyperthermia could be proposed as an efficient approach to enhance radiation effects in cancer cells.

Proteomic analysis of circulating extracellular vesicles identifies potential markers of breast cancer progression, recurrence, and response

Proteomic profiling of circulating small extracellular vesicles (sEVs) represents a promising, noninvasive approach for early detection and therapeutic monitoring of breast cancer (BC). We describe a relatively low-cost, fast, and reliable method to isolate sEVs from plasma of BC patients and analyze their protein content by semiquantitative proteomics. sEV-enriched fractions were isolated from plasma of healthy controls and BC patients at different disease stages before and after surgery. Proteomic analysis of sEV-enriched fractions using reverse phase protein array revealed a signature of seven proteins that differentiated BC patients from healthy individuals, of which FAK and fibronectin displayed high diagnostic accuracy. The size of sEVs was significantly reduced in advanced disease stage, concomitant with a stage-specific protein signature. Furthermore, we observed protein-based distinct clusters of healthy controls, chemotherapy-treated and untreated postsurgery samples, as well as a predictor of high risk of cancer relapse, suggesting that the applied methods warrant development for advanced diagnostics.

Klotho Alleviates Lung Injury Caused by Paraquat via Suppressing ROS/P38 MAPK-Regulated Inflammatory Responses and Apoptosis

Acute lung injury (ALI) induced by paraquat (PQ) progresses rapidly with high mortality; however, there is no effective treatment, and the specific mechanism is not well understood. The antiaging protein klotho (KL) has multiple functions and exerts significant influences on various pathophysiological processes. This work evaluated the impact of KL on PQ-induced ALI and investigated its underlying mechanisms. As for in vivo research, C57BL/6 mice were treated with PQ (30 mg/kg) intraperitoneal (IP) injection to create a toxicity model of ALI (PQ group). The mice were divided into control group, KL group, PQ group, and PQ+KL group. For in vitro experiment, A549 cells were incubated with or without KL and then treated in the presence or absence of PQ for 24 h. In vivo result indicated that KL reduced the mortality, reduced IL-1β and IL-6 in the bronchoalveolar lavage fluid (BALF), attenuated ALI, and decreased apoptosis in situ. In vitro result revealed that KL significantly improved cell viability, reduced the levels of IL-1β and IL-6 in culture supernatants, suppressed cell apoptosis, inhibited caspase-3 activation, and enhanced mitochondrial membrane potential (ΔΨm) after PQ treatment. Besides, KL effectively abated reactive oxygen species (ROS) production, improved GSH content, and lowered lipid peroxidation in PQ-exposed A549 cells. Further experiments indicated that phosphorylated JNK and P38 MAPK was increased after PQ treatment; however, KL pretreatment could significantly lower the phosphorylation of P38 MAPK. Suppression of P38 MAPK improved cell viability, alleviated inflammatory response, and reduced apoptosis-related signals; however, it had no obvious effect on the production of ROS. Treatment with N-acetylcysteine (NAC), a classic ROS scavenger, could suppress ROS production and P38 MAPK activation. These findings suggested that KL could alleviate PQ-caused ALI via inhibiting ROS/P38 MAPK signaling-regulated inflammatory responses and mitochondria-dependent apoptosis.

Building radiation-resistant model in triple-negative breast cancer to screen radioresistance-related molecular markers

Background

To build the triple-negative breast cancer (TNBC) radiation resistance model in vitro and vivo, and screen the molecular markers that related to radiation resistance.

Methods

We used X-ray to irradiate MDA-MB-231 cells repeatedly to build radioresistant cell (231-RR), then select one gemcitabine-resistance of MDA-MB-231 cell (231-GEM). We screen differentially expressed genes of these cell lines. Then, we would select 2 genes of them associated with DNA damage repair or cell cycle, and build RNAi lentivirus vector to knock down related gene. We also used X-rays repeatedly exposure TNBC tumor xenograft to build tumor with radioresistance properties, and then verify previously screening differentially expressed genes using IHC. Finally, we used The Cancer Genome Atlas (TCGA) database to validate the relationships between radioresistance related genes and the prognosis of breast cancer.

Results

We got 161 up-regulated genes and 156 down-regulated genes from three cell lines. Cellular results show the 231-cell with knock-down CDKN1A or SOD2 gene, its radiation sensitivity was significantly enhanced. We successfully got the TNBC xenograft tumor with radioresistance properties. Immunohistochemical results show that the radioresistance of tumor tissue with higher p21 (CDKN1A encoding protein) and SOD2 expression (P<0.01). The prognosis of patients with low SOD2 expression is better than that of high expression, but have no statistical significance (P=0.119); patients with low CDKN1A expression is significantly better than high expression (P=0.000). Multivariate cox analysis manifest that CDKN1A gene expression level is an independent prognostic factor in breast cancer patient (P=0.008).

Conclusions

Construction of radiation resistance cell and xenograft tumor with radio-resistant properties model for radiation biology research is feasible. High SOD2 and CDKN1A is associated with the poor prognosis in breast cancer patients. These two genes could be used as a predicted makers of breast cancer radiation sensitivity.

MicroRNA Assisted Gene Regulation in Colorectal Cancer

Colorectal cancer (CRC) is the second-leading cause of cancer death and a major public health problem. Nearly 80% CRC cases are diagnosed after the disease have metastasized and are often too advanced for treatment. Small non-coding RNA guides argonaute protein to their specific target for regulation as the sole of RNA induced silencing complex for gene silencing. These non-coding RNA for example microRNA, are thought to play a key role in affecting the efficiency of gene regulation in cancer, especially CRC. Understanding the mechanism at the molecular level could lead to improved diagnosis, treatment, and management decisions for CRC. The study aimed to predict the molecular mechanism of gene regulation based microRNA-mRNA duplex as a lead in the silencing mechanism. Five candidate microRNAs were identified through the in silico approach. The MicroRNA target prediction and subsequent correlation, and prioritization were performed using miRTarBase, gbCRC and CoReCG, and DAVID databases respectively. Protein selection and preparation were carried out using PDB and Schrödinger suits. The molecular docking analysis was performed using PATCHDOCK webserver and visualized by discovery studio visualizer. The results of the study reveal that the candidate microRNAs have strong binding affinity towards their targets suggesting a crucial factor in the silencing mechanism. Furthermore, the molecular docking of the receptor to both the microRNA and microRNA-mRNA duplex were analyzed computationally to understand their interaction at the molecular level. Conclusively, the study provides an explanation for understanding the microRNAs-based gene regulation (silencing mechanism) in CRC.

Ghrelin ameliorates A549 cell apoptosis caused by paraquat via p38-MAPK regulated mitochondrial apoptotic pathway

Paraquat has relatively strong detrimental effects on humans and animals and can cause acute lung injury with high mortality. Ghrelin is a brain-gut peptide which plays important roles in regulating various physiological processes. This study investigated whether ghrelin could inhibit paraquat-induced lung injuries and attempted to elucidate the possible molecular mechanisms. A549 cells were preincubated with different concentrations of ghrelin and then treated with 200 μM of PQ for 24 h. Then cell survival, apoptosis, cellular oxidative stress and lipid peroxidation of A549 cells were detected after different treatments. Subsequently, we analyzed the mitochondrial membrane potential (ΔΨm) and measured caspase-3 activation in A549 cells. In addition, we investigated the activation of the MAPKs pathway and the function of p38-MAPK within mitochondrial apoptosis. Our study indicated that ghrelin administration improved cell viability and reduced apoptosis of PQ-treated A549 cells dose-dependently. Ghrelin treatment reduced the elevation of ROS and MDA, while improved GSH content in A549 cells after paraquat exposure. Moreover, we found that ghrelin dose-dependently increased ΔΨm and decreased caspase-3 activity. The phosphorylated p38 MAPK and JNK levels elevated following PQ exposure, while the phosphorylation of p38 MAPK decreased following ghrelin pretreatment. p38 MAPK siRNA or SB203580 pretreatment ameliorated PQ-caused cell injury and apoptosis related signals, however, the intracellular ROS production was not affected. N-Acetylcysteine (NAC), a classic antioxidant pretreatment decreased the phosphorylated p38 MAPK level and intracellular ROS production, alleviated cell injury, and inhibited apoptosis. The results showed that p38-MAPK pathway plays an important role in PQ-caused alveolar epithelial cell insult, and ghrelin might attenuate PQ-induced cell injury by inhibiting ROS-induced p38-MAPK modulated mitochondrial apoptotic pathway.

LPS protects macrophages from AIF-independent parthanatos by downregulation of PARP1 expression, induction of SOD2 expression, and a metabolic shift to aerobic glycolysis

In inflamed tissues or during ischemia-reperfusion episodes, activated macrophages produce large amounts of reactive species and are, thus, exposed to the damaging effects of reactive species. Here, our goal was to investigate the mechanism whereby activated macrophages protect themselves from oxidant stress-induced cell death. Hydrogen peroxide-treated mouse bone marrow-derived macrophages (BMDM) and THP-1 human monocyte-derived cells were chosen as models. We found a gradual development of resistance: first in monocyte-to-macrophage differentiation, and subsequently after lipopolysaccharide (LPS) exposure. Investigating the mechanism of the latter, we found that exposure to intense hydrogen peroxide stress causes poly(ADP-ribose) polymerase-1 (PARP-1) dependent programmed necrotic cell death, also known as parthanatos, as indicated by the protected status of PARP-1 knockout BMDMs and the protective effect of the PARP inhibitor PJ-34. In hydrogen peroxide-treated macrophages, however, apoptosis inducing factor (AIF) proved dispensable for parthanatos; nuclear translocation of AIF was not observed. A key event in LPS-mediated protection against the hydrogen peroxide-induced AIF independent parthanatos was downregulation of PARP1 mRNA and protein. The importance of this event was confirmed by overexpression of PARP1 in THP1 cells using a viral promoter, which lead to stable PARP1 levels even after LPS treatment and unresponsiveness to LPS-induced cytoprotection. In BMDMs, LPS-induced PARP1 suppression lead to prevention of NAD⁺ depletion. Moreover, LPS also induced expression of antioxidant proteins (superoxide dismutase-2, thioredoxin reductase 1 and peroxiredoxin) and triggered a metabolic shift to aerobic glycolysis, also known as the Warburg effect. In summary, we provide evidence that in macrophages intense hydrogen peroxide stress causes AIF-independent parthanatos from which LPS provides protection. The mechanism of LPS-mediated cytoprotection involves downregulation of PARP1, spared NAD⁺ and ATP pools, upregulation of antioxidant proteins, and a metabolic shift from mitochondrial respiration to aerobic glycolysis.

Clair WH, St. Clair DK. Redox Paradox: A Novel Approach to Therapeutics-Resistant Cancer

SIGNIFICANCE

Cancer cells that are resistant to radiation and chemotherapy are a major problem limiting the success of cancer therapy. Aggressive cancer cells depend on elevated intracellular levels of reactive oxygen species (ROS) to proliferate, self-renew, and metastasize. As a result, these aggressive cancers maintain high basal levels of ROS compared with normal cells. The prominence of the redox state in cancer cells led us to consider whether increasing the redox state to the condition of oxidative stress could be used as a successful adjuvant therapy for aggressive cancers. Recent Advances: Past attempts using antioxidant compounds to inhibit ROS levels in cancers as redox-based therapy have met with very limited success. However, recent clinical trials using pro-oxidant compounds reveal noteworthy results, which could have a significant impact on the development of strategies for redox-based therapies.

CRITICAL ISSUES

The major objective of this review is to discuss the role of the redox state in aggressive cancers and how to utilize the shift in redox state to improve cancer therapy. We also discuss the paradox of redox state parameters; that is, hydrogen peroxide (H2O2) as the driver molecule for cancer progression as well as a target for cancer treatment.

FUTURE DIRECTIONS

Based on the biological significance of the redox state, we postulate that this system could potentially be used to create a new avenue for targeted therapy, including the potential to incorporate personalized redox therapy for cancer treatment.

MIIP gene expression is associated with radiosensitivity in human nasopharyngeal carcinoma cells

The present study aims to investigate the radiosensitization effect of the migration and invasion inhibitory protein (MIIP) gene on nasopharyngeal carcinoma (NPC) cells. The MIIP gene was transfected into NPC 5-8F and CNE2 cells. The level of MIIP was analyzed by quantitative reverse transcription-polymerase chain reaction analysis and western blot. The changes in radiosensitivity of the cells were analyzed by colony formation assay. The changes in cell apoptosis and cycle distribution following irradiation were detected by flow cytometry. The expression of BCL2 associated X, apoptosis regulator/B-cell lymphoma 2 was evaluated using western blot. DNA damage was analyzed by counting γ-H2AX foci. The expression levels of γ-H2AX were evaluated by immunofluorescence and western blot. In a previous study by the authors, the results indicated that the expression of MIIP gene evidently increased in MIIP-transfected 5-8F (5-8F OE) and MIIP-transfected CNE2 (CNE2 OE) cells compared with the parental or negative control cells. In the present study, the survival rate of 5-8F OE and CNE2 OE cells markedly decreased following irradiation (0, 2, 4, 6 and 8 Gy) compared with the negative control (5-8F NC and CNE2 NC) and the untreated (5-8F and CNE2) groups. The expression of MIIP was able to increase apoptosis, which resulted in G2/M cell cycle arrest and DNA damage repair was attenuated in 5-8F and CNE2 cells following irradiation as measured by the accumulation of γ-H2AX. It was indicated that MIIP expression is associated with the radiosensitivity of NPC cells and has a significant role in regulating cell radiosensitivity.

Protective effect of mitochondrial-targeted antioxidant MitoQ against iron ion 56Fe radiation induced brain injury in mice

Exposure to iron ion ⁵⁶Fe radiation (IR) during space missions poses a significant risk to the central nervous system and radiation exposure is intimately linked to the production of reactive oxygen species (ROS). MitoQ is a mitochondria-targeted antioxidant that has been shown to decrease oxidative damage and lower mitochondrial ROS in a number of animal models. Therefore, the present study aimed to investigate role of the mitochondrial targeted antioxidant MitoQ against ⁵⁶Fe particle irradiation-induced oxidative damage and mitochondria dysfunction in the mouse brains. Increased ROS levels were observed in mouse brains after IR compared with the control group. Enhanced ROS production leads to disruption of cellular antioxidant defense systems, mitochondrial respiration dysfunction, altered mitochondria dynamics and increased release of cytochrome c (cyto c) from mitochondria into cytosol resulting in apoptotic cell death. MitoQ reduced IR-induced oxidative stress (decreased ROS production and increased SOD, CAT activities) with decreased lipid peroxidation as well as reduced protein and DNA oxidation. MitoQ also protected mitochondrial respiration after IR. In addition, MitoQ increased the expression of mitofusin2 (Mfn2) and optic atrophy gene1 (OPA1), and decreased the expression of dynamic-like protein (Drp1). MitoQ also suppressed mitochondrial DNA damage, cyto c release, and caspase-3 activity in IR-treated mice compared to the control group. These results demonstrate that MitoQ may protect against IR-induced brain injury.

Effects of over-expression of SOD2 in bone marrow-derived mesenchymal stem cells on traumatic brain injury

Intravenous administration of bone marrow-derived mesenchymal stem cells (BM-MSCs) has been shown to promote nerve cell regeneration following traumatic brain injury (TBI). As the anti-oxidant defense systems in neuronal tissue including superoxide dismutase 2 (SOD2) are crucial to defend cell against oxidative stress. We proposed a new stratege to increase the therapeutic effect of MSCs by preventing cells death from oxidative stress. We overexpressed SOD2 in BM-MSCs, transplanted these MSCs into TBI model mice, assessed the protective effect of SOD2 against oxidation-induced apoptosis in BM-MSCs both in vitro and in vivo, evaluated brain functional recovery by the rotarod behavioral test, and tested the oxidation status of TBI mice brain after BM-MSCs transplantation by monitoring the superoxide dismutase, glutathione and malonaldehyde level. We found over-expression of SOD2 protected BM-MSCs from H₂O₂-induced cell apoptosis. Injection of SOD2 over-expressed BM-MSCs attenuated neuro-inflammation in the ipsilateral cortex of TBI mice, and protected TBI mice against loss of blood-brain barrier integrity. Furthermore, the rotarod behavioral test showed functional recovery of TBI mice after MSC treatment. Our experiments indicated that SOD2-over-expressed BM-MSCs have an improved therapeutic effect on brain injury treatment in TBI mice.