Mechanistic approach of the therapeutic potential of mesenchymal stem cells on brain damage in irradiated mice: emphasis on anti-inflammatory and anti-apoptotic effects

BACKGROUND AND OBJECTIVES

Brain damage which has been induced by radiation generally occurs in radiotherapeutics patients. Stem cell transplantation represents a vital applicant for alleviating neurodegenerative disorders. This work aims at exploring the potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) on brain injury induced by γ radiation in mice and the possible underlying mechanisms were elucidated.

MATERIALS AND METHODS

Mice were allocated into three groups; Group I (Control), Group II (Irradiated control) where mice submitted to 5 Gy of whole-body γ radiation, Group III (Irradiated + BM-MSCs) where mice were intravenously injected of BM-MSCs at a dose of 106 cells/mice 24 h following irradiation. Animals were sacrificed 28 d following exposure to γ radiation.

RESULTS

It was observed that BM-MSCs therapy provided a valuable tissue repair as evidenced by a reduction in inflammatory mediators including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), nuclear factor kappa (NF-κβ), phosphorylated NF-κβ-p65 (P-NF-κβ-p65), interferon-gamma (IFNγ) and monocyte chemoattractant protein-1 (MCP-1) associated with decreased levels of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) in brain tissues of irradiated mice. Furthermore, neuronal apoptosis was declined in brain tissues of the BM-MSCs group as remarkable inhibition of caspase-3 and Bax accompanied by elevation of Bcl-2 proteins expression. These results were supported by histopathological investigation.

CONCLUSIONS

In conclusion, BM-MSCs could display a vital rule in alleviating brain injury in radio-therapeutic patients.

Synthesis, characterization and evaluation of resveratrol-loaded functionalized carbon nanotubes as a novel delivery system in radiation enteropathy

Radiation-induced enteropathy is a major clinical challenge during radiotherapy. Resveratrol displays beneficial pharmacological activities; however, low oral bioavailability limits its effectiveness. This study aims at preparing methacrylic acid (MAAc) functionalized multi-walled carbon nanotubes (MWCNTs-MAAc) as carriers for pH triggered controlled release of resveratrol in an effort to improve the drug therapeutic potential. MWCNTs-MAAc were prepared using radiation technique and then characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform-infrared (FT-IR) spectroscopy. In vitro drug release profile at different pH values was analyzed. Furthermore, the designed RES-MWCNTs-MAAc nanocomplex was evaluated against radiation-induced enteropathy in rats. Oral administration of RES-MWCNTs-MAAc restored colonic redox state and elevated antioxidant enzymes activities glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) and reduced colonic inflammatory mediators tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interferone-γ (IFN-γ) contents in addition to declining the intrinsic apoptotic pathway as evidenced by down-regulation of Bax and caspase-3 proteins expression accompanied by up-regulation of Bcl-2 protein expression. RES-MWCNTs-MAAc was more efficient than free resveratrol due to the delivery system that allowed prolonged resveratrol release at target site. Thus, this formulation could serve as a beneficial anti-inflammatory approach for patients during radiotherapy.

Low dose γ radiation enhances antidepressant effect of resveratrol: Behavioral and neurochemical studies

The low dose of radiation (LDR) has received growing attention for its beneficial neuroprotective effect. This study was designed to investigate the enhancing effect of LDR on the antidepressant potential of resveratrol against diazepam-induced depression in mice. Female mice divided into five groups; control, diazepam (2 mg/kg), LDR (0.5Gy) + diazepam, resveratrol (20 mg/kg) + diazepam, LDR + resveratrol+diazepam. Mice received diazepam showed depressive symptoms as evidenced by decreased locomotor activity in the open field and increased immobility time in the forced swimming and tail suspension tests integrated with a marked decline in biogenic amines (serotonin, norepinephrine, and dopamine) in brain tissues. These effects were ameliorated by LDR or resveratrol administration demonstrating an antidepressant activity. Interestingly, LDR triggered the antidepressant effect of resveratrol as it restored the changes in behavioral tests, neurotransmitters, and neuro-histoarchitecture. In conclusion, these findings suggested that LDR could be considered as a novel adjuvant that augmented the resveratrol antidepressant effect and might serve as a potential therapeutic approach for depression.

Resveratrol attenuates intestinal injury in irradiated rats via PI3K/Akt/mTOR signaling pathway

Radiation-induced enteritis is one of the greatest challenges in radiotherapy. The current study was designed to evaluate the ameliorative effect of resveratrol, which exhibits anti-inflammatory property, against radiation-induced intestinal injury in rats and to explore the underlying mechanism. Rats were exposed to a single dose of 5 Gy. Resveratrol (20 mg/kg/day) was orally administered to irradiated rats over 3 weeks. Results showed that resveratrol ameliorated the intestinal oxidative stress parameters; malondialdehyde (MDA) content, glutathione (GSH) level, and catalase (CAT) activity compared to irradiated group. Furthermore, resveratrol reduced the contents of inflammatory cytokines; tumor necrosis factor α (TNF-α), nuclear factor-kappa (NF-κB), and interleukin 1β (IL-1β) in intestine. Western blotting analysis revealed that resveratrol down-regulated the proteins expression of phosphoinositide 3-kinases (PI3K), protein kinase B (Akt) as well as the mammalian target of rapamycin (mTOR) in intestinal tissues of irradiated rats and thus reduced the inflammatory mediator production. These results were confirmed by histopathological investigation. In conclusion, resveratrol attenuated intestinal inflammation following irradiation via modulating PI3K/Akt/mTOR pathway and thereby could be a promising adjuvant in radiotherapy.

Prophylactic Effect of Opuntia ficus indica Fruit Peel Extract against Irradiation-Induced Colon Injury in Rats

Opuntia ficus-indica extract has been used in traditional folk medicine for several purposes and exhibits anti-inflammatory properties. This study was directed to explore the prophylactic effect of O. ficus-indica fruit peel extract against irradiation-induced colitis in rats. GC/MS analysis of the petroleum ether extract led to recognition of 33 compounds in the unsaponifiable fraction and 15 fatty acid methyl esters in the saponifiable part. Thirteen terpenes and sterols were isolated and identified from which ten compounds were not isolated from any part of this species before. Data showed that irradiation induced colon injury as manifested by elevated contents of malondialdehyde, nitric oxide, myeloperoxidase, intercellular adhesion molecule-1, cyclooxygenase-2, tumor necrosis factor alpha, and nuclear factor kappa B, while it reduced superoxide dismutase activity and interleukin 10 content in colonic tissues, which was confirmed by histopathological examination. Pretreatment with O. ficus-indica extract attenuated the alteration in the measured parameters. It could be concluded that O. ficus-indica fruit peel extract can be regarded as a potential agent in limiting colonic complications due to irradiation, possibly by its antioxidant and anti-inflammatory properties.

Gamma radiation preparation of chitosan nanoparticles for controlled delivery of memantine

The purpose of the current study is to prepare chitosan nanoparticles by gamma radiation as a new brain delivery system for memantine to improve its therapeutic efficiency. Fourier-transform infrared analysis of chitosan nanoparticles showed the characteristic peaks of chitosan and the reduction of particle size induced by irradiation at doses 10, 20 and 30 kGy. The solubility of chitosan nanoparticles was tested using different solvents and exhibited good solubility in both water and 1% acetic acid than other tested solvents at 80°C. Different formulations containing memantine -loaded chitosan nanoparticles were evaluated for brain targeting on aluminum-induced Alzheimer’s disease in rats. Memory deficit was evaluated using the Morris water maze test. The levels of amyloid-β peptide, tumour necrosis factor alpha, interleukin-1β and interleukin-6 in brain tissues as well as the serum level of brain-derived neurotrophic factor were assayed. Data demonstrated that memantine -loaded chitosan nanoparticles 1:1 transported memantine effectively into the brain compared to free memantine as evidenced by better behaviour performance and biochemical amelioration and confirmed by histopathological examination in Alzheimer’s disease rats. Interestingly, the therapeutic effect of memantine -loaded chitosan nanoparticles 1:1 was superior to memantine -loaded chitosan nanoparticles 1:2 and memantine -loaded chitosan nanoparticles 2:1. Based on these findings, it is reasonable to suggest that memantine -loaded chitosan nanoparticles 1:1 could be a promising approach for Alzheimer’s disease.

Pioglitazone ameliorates hepatic damage in irradiated rats via regulating anti-inflammatory and antifibrogenic signalling pathways

Hepatic irradiation during radiotherapy is associated with liver damage. The current study was designed to investigate the possible modulatory effects of pioglitazone against γ irradiation-induced hepatic damage in rats. Animals were exposed to a single dose of 6 Gy and received pioglitazone (10 mg/kg/day) orally for 4 weeks starting on the same day of irradiation. Results showed that irradiation increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities as well as serum triglyceride (TG) and total cholesterol (TC) levels. Furthermore, it elevated inflammatory mediators; tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6); nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) in hepatic tissues. Moreover, it increased levels of serum fibrotic markers; hyaluronic acid (HA), laminin (LN), and type III procollagen (PCIII). Additionally, hepatic fibrotic markers; transforming growth factor-β1 (TGF-β1) and hydroxyproline (HP) levels were elevated. Histological analysis of H&E and MT staining of liver sections exhibited cellular infiltration and fibrous deposition in irradiated rats. It was observed that pioglitazone modulated the described deviations. In conclusion, pioglitazone could serve as a promising therapeutic tool for attenuating radiation-induced liver injury in patients with radiotherapy which might be attributed to its anti-inflammatory and antifibrotic activities.

Nigella sativa oil modulates the therapeutic efficacy of mesenchymal stem cells against liver injury in irradiated rats

Stem cell transplantation is a novel strategy for regenerative medicine in liver disease. This study was conducted to explore the modulatory effect of Nigella sativa oil (NSO) on the therapeutic potential of mesenchymal stem cells (MSCs) against irradiation-induced liver damage in rats. Liver damage was induced by a total body exposure to a single dose of 7Gy. NSO (2mg/kg/day) was then given orally for 4 consecutive weeks starting 24h after irradiation with or without a single intravenous MSCs administration, then rats were sacrificed four weeks after exposure to γ radiation. Data revealed that irradiation elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in serum, increased hepatic malondialdehyde (MDA) content and reduced hepatic superoxide dismutase (SOD) activity. Furthermore, it caused elevation in pro-inflammatory mediators such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) associated with reduction in anti-inflammatory cytokine interleukin-10 (IL-10) and it increased fibrogenic marker transforming growth factor-β (TGF-β) in liver tissues. It was observed that combined NSO/MSCs therapy provided more beneficial tissue repair comparable to MSCs alone as demonstrated by modulating the tested parameters. Finally, these results were confirmed by histopathological examination. In conclusion, dual therapy with NSO and MSCs could serve as a promising approach for alleviating radiation-induced liver injury in patients with radiotherapy.

Antioxidant and antiapoptotic effects of sea cucumber and valsartan against doxorubicin-induced cardiotoxicity in rats: The role of low dose gamma irradiation

Doxorubicin (DOX) is a highly effective antineoplastic drug; however, the clinical use of DOX is limited by its dose dependent cardiotoxicity. This study was conducted to evaluate the cardioprotective effect of sea cucumber and valsartan against DOX-induced cardiotoxicity in rats. Also, the role of exposure to low dose γ radiation (LDR) on each of them was investigated, since LDR could suppress various reactive oxygen species-related diseases. Rats received DOX (2.5mg/kg, ip) in six equal injections over a period of 2weeks, sea cucumber (14.4mg/kg, p.o) and valsartan (30mg/kg, p.o) for 8 successive weeks. Exposure to LDR (0.5Gy) was performed one day prior to DOX. Results revealed that DOX administration elevated serum levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK-MB) and troponin-I as well as increased cardiac lipid peroxide content and myeloperoxidase (MPO) activity. Additionally, it increased cardiac expressions of iNOS and caspase-3, accompanied by reduction in cardiac total protein and glutathione (GSH) contents. Treatment with sea cucumber or valsartan improved the cardiotoxicity of DOX. Their adjuvant therapy with LDR offers an additional benefit to the cardioprotection of the therapeutic drugs. These results confirmed by histopathological examination. In conclusion, sea cucumber and valsartan alone or combined with LDR attenuated DOX-induced cardiotoxicity via their antioxidant and anti-apoptotic activities and thus might be useful in the treatment of human patients under doxorubicin chemotherapy.