Rat Model Of Degeneration Research Articles

Regenerative Outcomes of Combining siCOL1A2 Hydrogel with Acupuncture in a Rat Model of Chronic Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IVDD) is a significant cause of chronic pain and disability, necessitating innovative therapeutic strategies. This study investigates the combined effect of a novel siCOL1A2-encapsulated hydrogel and acupuncture on IVDD in a rat model. We developed a hydrogel system, siCOL1A2-encapsulated G5-PBA hydrogel (siCOL1A2@G5-PBA@Gel), designed for sustained siRNA delivery to the degenerated discs and assessed its therapeutic efficacy alongside acupuncture treatment. Key inflammatory genes were identified through RNA-seq analysis, with COL1A2 highlighted as a crucial regulator of inflammatory responses in IVDD. Our in vivo experiments involved treating rats with hydrogel alone, acupuncture alone, and combining both. The treatments were evaluated through behavioral pain assessments, imaging techniques (X-ray and MRI), and histological analyses. Results indicated that the combination therapy significantly alleviated pain, reduced inflammation, and promoted disc regeneration more effectively than individual treatments. The hydrogel proved biocompatible and facilitated targeted gene silencing, while acupuncture enhanced therapeutic outcomes by improving local blood circulation and modulating inflammatory responses. These findings suggest that integrating siCOL1A2 hydrogel with acupuncture offers a promising approach to treating IVDD.

Magnetic resonance imaging classification in a percutaneous needle injury rat model of intervertebral disc degeneration

BackgroundDuring the development of disease-modifying intervertebral disc degeneration (IDD) drugs, the rat model of IDD is frequently used for disease progression assessment. The aim of this study was to describe a magnetic resonance (MRI) scoring system for the assessment of different disc conditions in puncture-induced IDD, allowing standardization and comparison of results obtained by different investigators.MethodsA total of 36 Sprague-Dawley rats were utilized in the present study. The animals were divided into two groups: a sham group and an IDD group caused by puncture. The rats in the IDD group were subsequently divided into six categories based on time frames, with five rats in each category. The sham group was divided into two sub-groups (n = 3) for 28 and 56 days, respectively. T2-weighted images of rats consecutively studied with MRI of the coccygeal discs were classified according to the time course using the corresponding histological data. Additional scoring of the micro-CT was employed to identify the progression of bone destruction of the rat model of IDD.ResultsA comparison of the MRI results between the sham group and the IDD group revealed a significant reduction in NP height, area, T2WI value, and DHI in the latter group (P < 0.05). The micro-CT results demonstrated that following acupuncture, there was a notable decline in the BV, Tb.N, and height of the coccygeal vertebra, while the BS/BV and Tb.Sp exhibited a significant increase (P < 0.05). The histological results were analogous to the MRI results, indicating a progressive exacerbation of IDD and a corresponding increase in NP score (P < 0.05). The results of the MRI were found to be consistent with those of the micro-CT and histological analyses (P < 0.05). The results of the study demonstrate a robust correlation between MRI analysis and histological findings. Live animals are employed for MRI analysis to improve experiment comparability. The reliability of the MRI scoring system ensures assessment of disease progression in live animals, while promoting cost savings and animal welfare by avoiding the sacrifice of animals at different times.ConclusionsThe described scoring paradigm has quantitatively been found to differentiate IDD disease progression in an in vivo rat model. Hence, we suggest employing it to evaluate the rat IDD model and assess the effects of treatments in this model.

Deciphering the Effect of Hyaluronic Acid/Collagen Hydrogel for Pain Relief and Tissue Hydration in a Rat Model of Intervertebral Disc Degeneration.

Intervertebral disc (IVD) degeneration is one of the primary causes of low back pain, causing disability; hence, there is no regenerative nature of the current treatments. Hyaluronic acid (HA) was reported to facilitate tissue repair and alleviate pain. Herein, we determined the therapeutic effect of HA and type II collagen (COLII) hydrogel for tissue repair targeting pain in IVD degeneration. We implanted HA/COLII hydrogel following surgically induced disc injury at coccygeal levels in the rat tail model of pain. We assessed the efficacy of the HA/COLII hydrogel in reducing pain behaviour by using the von Frey assessment, protein expression of growth-associated protein (GAP) 43 for sensory nerve innervation, and disc hydration by magnetic resonance imaging (MRI). We observed the anti-nociceptive effect of the HA/COLII hydrogel in alleviating mechanical allodynia in rats. There was an inhibition of sensory hyperinnervation indicated by the GAP43 protein in the treatment group. We revealed an increase in T1ρ mapping of MRI, indicating that the hydrogel restored disc hydration in vivo. Our findings suggest the HA/COLII hydrogel alleviates pain behaviour, inhibits hyperinnervation and promotes disc hydration for tissue repair, implying that it is a potential candidate for the treatment of degenerative disc-associated low back pain.

Intratympanic injection of MSC-derived small extracellular vesicles protects spiral ganglion neurons from degeneration

Sensorineural hearing loss is one of the most prevalent sensory deficits. Spiral ganglion neurons (SGNs) exhibit very limited regeneration capacity and their degeneration leads to profound hearing loss. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEV) have been demonstrated to repair tissue damage in various degenerative diseases. However, the effects of MSC-sEV on SGN degeneration remain unclear. In this study, we investigated the efficacy of MSC-sEV for protection against ouabain-induced SGN degeneration. MSC-sEV were derived from rat bone marrow and their components related to neuron growth were determined by proteomic analysis. In primary culture SGNs, MSC-sEV significantly promoted neurite growth and growth cone development. The RNA-Seq analysis of SGNs showed that enriched pathways include neuron development and axon regeneration, consistent with proteomics. In ouabain induced SGN degeneration rat model, MSC-sEV administration via intratympanic injection significantly enhanced SGN survival and mitigated hearing loss. Furthermore, after ouabain treatment, SGNs displayed evident signs of apoptosis, including nuclei condensation and fragmentation, with numerous cells exhibiting TUNEL-positive. However, administration of MSC-sEV effectively decreased the number of TUNEL-positive cells and reduced caspase-3 activation. In conclusion, our findings demonstrate the potential of MSC-sEV in preventing SGN degeneration and promoting neural growth, suggesting intratympanic injection of MSC-sEV is a specific and efficient strategy for neural hearing loss.

Exploring the protective effects of Qiju Granule in a rat model of dry age-related macular degeneration

AimThe aim of this study was to evaluate the potential protective effect of Qiju Granule in a rat model of age-related macular degeneration (AMD) and investigate the underlying mechanisms involved. MethodsRats were injected intravenously with 40 mg/kg of sodium iodate (SI) to induce a dry AMD model. The rats in the treatment group received three different doses of Qiju Granule once a day via gavage, while the rats in the control group were given an equal volume of physiological saline. On day 14 and day 28 following the intervention, various methods were employed to evaluate retinal function and structure, including electroretinography (ERG), optical coherence tomography (OCT), and histological examination. The expression of glial fibrillary acidic protein (GFAP), basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) was assessed via immunofluorescence. Beyond immunofluorescence, the mRNA levels of bFGF, BDNF, and CNTF were quantitatively determined using real-time polymerase chain reaction (qRT-PCR). ResultsRats treated with Qiju Granule exhibited significant improvements in both retinal function and structure compared to the model group. The most noteworthy effects were observed at a high dose of Qiju Granule. Furthermore, the expression levels of bFGF, BDNF, and CNTF were significantly unregulated in the treated groups compared to the model group. ConclusionsQiju Granule demonstrated a protective effect on the retina in the SI-induced rat model of AMD. The protective mechanism may be attributed to the upregulation of retinal neurotrophic factors expression.

Zhiqiao Gancao decoction regulated JAK2/STAT3/ macrophage M1 polarization to ameliorate intervertebral disc degeneration

BackgroundZhiqiao Gancao decoction (ZQGCD) was created by Professor Gong Zhengfeng, a renowned Chinese medicine expert. Clinical studies have shown its efficacy in alleviating pain and enhancing lumbar function in intervertebral disc degeneration (IDD) patients. However, the precise mechanism of ZQGCD in treating IDD remains unclear. MethodsThe active components of ZQGCD were identified using Liquid chromatography-tandem mass spectrometry (LC-MS/MS). A rat model of intervertebral disc degeneration was established, and rats in each group received ZQGCD for three weeks. Assessment parameters included hyperalgesia status, observation of intervertebral disc tissue degeneration and macrophage infiltration, and analysis of JAK2/STAT3 pathway protein expression in the intervertebral disc. Primary macrophage M1 polarization was induced using LPS, with cells treated using the JAK2 inhibitor (AZD1480) and ZQGCD to evaluate macrophage polarization, cellular supernatant inflammatory factors, and JAK2/STAT3 pathway expression. Macrophage supernatant served as a conditioned medium to observe its effects on the proliferation of nucleus pulposus cells (NPCs) and the expression of collagen II and MMP3 proteins. ResultsA total of 81 active components were identified in ZQGCD. Following ZQGCD treatment, infiltrating macrophages in intervertebral disc tissues of model rats decreased, the content of M1 macrophages decreased, while the content of M2 macrophages increased, the expression of proinflammatory factors and pain-inducing factors in serum decreased, and the expression of substance P in intervertebral disc tissue decreased. Consequently, the intervertebral disc degeneration and hyperalgesia of rats were improved. In vitro studies revealed that LPS induced M1 macrophage polarization. By inhibiting the JAK2/STAT3 pathway, both JAK2 inhibitors and ZQGCD effectively suppressed M1 polarization, resulting in decreased levels of IL-1β, IL-6, TNF-α, and various other inflammatory factors. Consequently, this inhibition led to a delay in the degeneration of NPCs. ConclusionThere is macrophage infiltration in the intervertebral disc tissue of IDD rats, and JAK2/STAT3 pathway is activated, macrophages are polarized to M1 type, resulting in inflammatory microenvironment, leading to intervertebral disc degeneration and hyperalgesia. ZQGCD exhibited a delaying effect on IDD and improved hyperalgesia by inhibiting the JAK2/STAT3/macrophage M1 polarization pathway.

Continuous Thymoquinone Administration Mitigates Sodium Iodate-Induced Retinal Degeneration in Rats

Purpose This study aimed to investigate the protective or therapeutic effect of thymoquinone (TQ) in a retinal degeneration rat model and its relationships with the retina ultrastructure, heme oxygenase 1 (HO-1), caspase-3, and RPE65 expressions and to determine whether TQ has a therapeutic effect at the biochemical level. Methods A total of 25 adult Wistar albino rats were divided into the following treatment groups: saline (control: CONT), CO (corn oil), sodium iodate (SI), TQ + SI, and SI + TQ injection groups. Retina morphology, RPE65, HO-1, and caspase-3 expression levels were evaluated using immunohistochemistry, and optical density was determined using ImageJ. Ultrastructural evaluations were performed with electron microscopy. Thiol-disulfide homeostatic parameters were examined in serum samples. Results Outer nuclear layer (ONL) thickness was significantly higher in the SI + TQ group compared to the SI group. The RPE65 expression significantly decreased in the SI group compared with the CONT and CO groups. A significant increase in RPE65 expression level and a significant decrease in caspase-3 expression level were found in the SI + TQ group compared with the SI group. The increase in HO-1 expression level was significantly higher in the TQ treatment groups, particularly in the SI + TQ group. In the SI and TQ + SI groups, the ONL thickness significantly decreased with a significant increase in caspase-3 expression compared to the CONT and CO groups. In the treatment groups, decreased organelle damage was observed on electron microscopy. In the SI + TQ group, the disulfide/native thiol and disulfide/total thiol ratios were significantly lower than all other groups, while the native/total thiol ratio was significantly higher than the other experimental groups. Conclusions The present study provides evidence that continuous TQ treatment can increase HO-1 and RPE65 expression and decrease apoptosis (caspase-3 levels), thereby preserving the retina at the ultrastructural level. Moreover, TQ administration can maintain thiol/disulfide homeostasis in SI-induced retinal degeneration-modelled rats.

Mingjing granule inhibits the subretinal fibrovascular membrane of two-stage laser-induced neovascular age-related macular degeneration in rats.

The study aims to investigate the protective effect of Mingjing granule (MG) in a fibrovascular membrane rat model of neovascular age-related macular degeneration (nAMD) and explore the underlying mechanism. The nAMD fibrovascular membrane model was established by two-stage laser photocoagulation. BN rats were randomly divided into four groups: the model group was gavaged with distilled water, the anti-VEGF group was given an intravitreous injection of ranibizumab, the MG + anti-VEGF group was gavaged with MG combined with an intravitreous injection of ranibizumab, and the normal group not modeled only fed conventionally. Lesions were evaluated by color fundus photograph, optical coherence tomography, fundus fluorescein angiography, and retinal pigment epithelial-choroid-sclera flat mount. The changes in the retinal structure were observed by histopathology. The expression of inflammatory cell markers F4/80, Iba-1, and glial fibrillary acidic protein (GFAP); the fibrosis-related factors collagen-1, fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor-beta (TGF-β); and the complement system-related factors C3a and C3aR in the retina were detected by immunofluorescence or qRT-PCR. The current study revealed that MG + anti-VEGF administration more significantly reduced the thickness of fibrovascular lesions, suppressed vascular leakage (exudation area and mean density value), inhibited the area of fibrovascular lesions, and restrained the formation of the fibrovascular membrane than the anti-VEGF agent alone in the two-stage laser-induced rat model. The fluorescence intensities of F4/80, Iba-1, collagen-1, fibronectin, TGF-β, and C3aR showed more significant inhibition in MG + anti-VEGF-treated rats than the anti-VEGF agent alone. The mRNA expression levels of F4/80, Iba-1, GFAP, collagen-1, fibronectin, α-SMA, TGF-β, and C3a showed lower levels in rats treated with MG + anti-VEGF than the anti-VEGF agent alone. Combining MG with anti-VEGF treatment inhibits the growth of the fibrovascular membrane more effectively than using anti-VEGF treatment alone. The mechanism underlying this effect may involve limiting inflammatory cell aggregation, controlling complement system activation, and decreasing the expression of the fibrotic protein.

Chondrocyte-targeted exosome-mediated delivery of Nrf2 alleviates cartilaginous endplate degeneration by modulating mitochondrial fission

BackgroundCartilaginous endplate (CEP) degeneration, which is an important contributor to intervertebral disc degeneration (IVDD), is characterized by chondrocyte death. Accumulating evidence has revealed that dynamin-related protein 1 (Drp1)-mediated mitochondrial fission and dysfunction lead to apoptosis during CEP degeneration and IVDD. Exosomes are promising agents for the treatment of many diseases, including osteoporosis, osteosarcoma, osteoarthritis and IVDD. Despite their major success in drug delivery, the full potential of exosomes remains untapped.Materials and methodsIn vitro and in vivo models of CEP degeneration were established by using lipopolysaccharide (LPS). We designed genetically engineered exosomes (CAP-Nrf2-Exos) expressing chondrocyte-affinity peptide (CAP) on the surface and carrying the antioxidant transcription factor nuclear factor E2-related factor 2 (Nrf2). The affinity between CAP-Nrf2-Exos and CEP was evaluated by in vitro internalization assays and in vivo imaging assays. qRT‒PCR, Western blotting and immunofluorescence assays were performed to examine the expression level of Nrf2 and the subcellular localization of Nrf2 and Drp1. Mitochondrial function was measured by the JC-1 probe and MitoSOX Red. Mitochondrial morphology was visualized by MitoTracker staining and transmission electron microscopy (TEM). After subendplate injection of the engineered exosomes, the degree of CEP degeneration and IVDD was validated radiologically and histologically.ResultsWe found that the cargo delivery efficiency of exosomes after cargo packaging was increased by surface modification. CAP-Nrf2-Exos facilitated chondrocyte-targeted delivery of Nrf2 and activated the endogenous antioxidant defence system in CEP cells. The engineered exosomes inhibited Drp1 S616 phosphorylation and mitochondrial translocation, thereby preventing mitochondrial fragmentation and dysfunction. LPS-induced CEP cell apoptosis was alleviated by CAP-Nrf2-Exo treatment. In a rat model of CEP degeneration, the engineered exosomes successfully attenuated CEP degeneration and IVDD and exhibited better repair capacity than natural exosomes.ConclusionCollectively, our findings showed that exosome-mediated chondrocyte-targeted delivery of Nrf2 was an effective strategy for treating CEP degeneration.Graphic abstract CAP-Nrf2-Exos delivered Nrf2 into CEP cells and alleviated LPS-induced apoptosis by inhibiting Drp1-mediated mitochondrial fission

Electroacupuncture improves apoptosis of nucleus pulposus cells via the IL-22/JAK2-STAT3 signaling pathway in a rat model of cervical intervertebral disk degeneration.

Cervical spondylosis (CS) is a prevalent disorder that can have a major negative impact on quality of life. Traditional conservative treatment has limited efficacy, and electroacupuncture (EA) is a novel treatment option. We investigated the application and molecular mechanism of EA treatment in a rat model of cervical intervertebral disk degeneration (CIDD). The CIDD rat model was established, following which rats in the electroacupuncture (EA) group received EA. For overexpression of IL-22 or inhibition of JAK2-STAT3 signaling, the rats were injected intraperitoneally with recombinant IL-22 protein (p-IL-22) or the JAK2-STAT3 (Janus kinase 2-signal transducer and activator of transcription protein 3) inhibitor AG490 after model establishment. Rat nucleus pulposus (NP) cells were isolated and cultured. Cell counting kit-8 and flow cytometry were used to analyze the viability and apoptosis of the NP cells. Expression of IL-22, JAK2 and STAT3 was determined using RT-qPCR. Expression of IL-22/JAK2-STAT3 pathway and apoptosis related proteins was detected by Western blotting (WB). EA protected the NP tissues of CIDD rats by regulating the IL-22/JAK2-STAT3 pathway. Overexpression of IL-22 significantly promoted the expression of tumor necrosis factor (TNF)-α, IL-6, IL-1β, matrix metalloproteinase (MMP)3 and MMP13 compared with the EA group. WB demonstrated that the expression of IL-22, p-JAK2, p-STAT3, caspase-3 and Bax in NP cells of the EA group was significantly reduced and Bcl-2 elevated compared with the model group. EA regulated cytokines and MMP through activation of IL-22/JAK2-STAT3 signaling in CIDD rat NP cells. We demonstrated that EA affected apoptosis by regulating the IL-22/JAK2-STAT3 pathway in NP cells and reducing inflammatory factors in the CIDD rat model. The results extend our knowledge of the mechanisms of action underlying the effects of EA as a potential treatment approach for CS in clinical practice.

Ginsenoside Rg3 exhibits anti-catabolic and anti-apoptotic effects in IL-1β treated human disc nucleus pulposus cells and in a rat model of disc degeneration by inactivating the MAPK pathway.

Intervertebral disc degeneration (IDD) is the major cause of degeneration of joint diseases. IDD is characterized by a large number of apoptosis of nucleus pulposus cells (NPCs) and extracellular matrix (ECM) degradation. Ginsenoside Rg3 is the active component extracted from ginseng and has a vital function in modulating diseases. This study aimed to investigate the regulatory functions of ginsenoside Rg3 in IDD. We established the IDD cell model via inducing NPCs with IL-1β. The rat model of IDD was established by fibrous ring puncture method. Cell apoptotic capability was assessed through TUNEL assay. The levels of catabolic proteases MMPs and ADAMTSs were tested by western blot and RT-qPCR. IL-1β induction notably promoted the apoptosis of NPCs, while ginsenoside Rg3 treatment reversed the promoting function of IL-1β. Furthermore, we found that MMP2, MMP3, Adamts4, and Adamts5 levels were increased in IL-1β-induced NPCs, while ginsenoside Rg3 treatment markedly reduced their levels. Additionally, ginsenoside Rg3 was found to suppress the IL-1β-stimulated p38 MAPK pathway in NPCs. In the IDD rat model, we found that ginsenoside Rg3 treatment can alleviate NPC degeneration, recover the arrangement of annulus fibrous, and preserve more proteoglycan matrix. Moreover, ginsenoside Rg3 reduced apoptosis and catabolism and inactivated the p38 MAPK pathway in IDD rats. Ginsenoside Rg3 exhibits anti-catabolic and anti-apoptotic effects in IL-1β-stimulated NPCs and IDD rats by inactivating MAPK pathway.

SEPHS1 attenuates intervertebral disc degeneration by delaying nucleus pulposus cell senescence through the Hippo-Yap/Taz pathway.

Nucleus pulposus cell (NPC) senescence is a major cause of intervertebral disc degeneration (IVDD). Oxidative stress and reactive oxygen species (ROS) play critical roles in regulating cell senescence. Selenophosphate synthetase 1 (SEPHS1) was reported to play an important role in mitigating oxidative stress in an osteoarthritis (OA) model by reducing the production of ROS, thereby, delaying the occurrence and development of osteoarthritis. In this study, we explored the, hitherto unknown, role of SEPHS1 in IVDD in vitro and in vivo using an interleukin-1β (IL-1β)-induced NPC senescence model and a rat needle puncture IVDD model, respectively. SEPHS1 delayed NPC senescence in vitro by reducing ROS production. Age-related dysfunction was also ameliorated by the overexpression of SEPHS1 and inhibition of the Hippo-Yap/Taz signaling pathway. In vivo experiments revealed that the overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz alleviated IVDD in rats. Moreover, a selenium (Se)-deficient diet and lack of SEPHS1 synergistically aggravated IVDD progression. Taken together, our results demonstrate that SEPHS1 plays a significant role in NPC senescence. Overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz can delay NPC senescence, restore the balance of extracellular matrix metabolism, and attenuate IVDD. SEPHS1 could be a promising therapeutic target for IVDD.NEW & NOTEWORTHY Selenophosphate synthetase 1 (SEPHS1) deficiency leads to an increase in reactive oxygen species levels and in the subsequent activation of the Hippo-Yap/Taz signaling pathway. In the rat model of intervertebral disc degeneration (IVDD), overexpression of SEPHS1 and inhibition of Hippo-YAP/Taz mitigated the progression of disc degeneration indicating the involvement of SEPHS1 in IVDD. SEPHS1 is a promising therapeutic target for IVDD.

The effects of Elgucare in a rat model of intervertebral disc degeneration

As an avascular tissue, the intervertebral disc (IVD) faces difficulties in obtaining nutrients and is prone to accumulating metabolic waste. The ensuing IVD degeneration (IVDD) causes symptoms such as low back pain. Traditional Chinese medicine has a millennia-long history of treating IVDD, with the advantages of safety and few adverse effects. Based on prior pharmacological research, the Chinese herbal formula Elgucare is abundant in the nutrients required by the IVD and can improve blood circulation, accelerating the removal of metabolic waste from the IVD. This study used a 23 G needle to surgically induce IVDD in a rat model. Thirty rats were randomly assigned to five groups: one that underwent sham surgery (Sham), one with IVDD that was not fed Elgucare (EGC-0), and three with IVDD that were fed Elgucare at different concentrations for six weeks (EGC-L, EGC-M, and EGC-H). Study parameters, including total body weight, plantar sensitivity to pain, gait analysis, IVD thickness, and IVD morphology, were used to assess the effects of Elgucare on IVDs. Our results showed that administering Elgucare to rats effectively reduced plantar tingling and improved swing speed during gait analysis. Elgucare also accelerated increases in IVD thickness and increased the proportion of IVD that returned to normal cellularity. The possible benefits of Elgucare include alleviating pain, improving mobility, and accelerating IVD repair, indicating its potential for use in IVD therapy.

A Redox Homeostasis Modulatory Hydrogel with GLRX3+ Extracellular Vesicles Attenuates Disc Degeneration by Suppressing Nucleus Pulposus Cell Senescence.

Characterized by nucleus pulposus (NP) cell senescence and extracellular matrix (ECM) degradation, disc degeneration is a common pathology for various degenerative spinal disorders. To date, effective treatments for disc degeneration are absent. Here, we found that Glutaredoxin3 (GLRX3) is an important redox-regulating molecule associated with NP cell senescence and disc degeneration. Using a hypoxic preconditioning method, we developed GLRX3+ mesenchymal stem cell-derived extracellular vehicles (EVs-GLRX3), which enhanced the cellular antioxidant defense, thus preventing reactive oxygen species (ROS) accumulation and senescence cascade expansion in vitro. Further, a disc tissue-like biopolymer-based supramolecular hydrogel, which was injectable, degradable, and ROS-responsive, was proposed to deliver EVs-GLRX3 for treating disc degeneration. Using a rat model of disc degeneration, we demonstrated that the EVs-GLRX3-loaded hydrogel attenuated mitochondrial damage, alleviated the NP senescence state, and restored ECM deposition by modulating the redox homeostasis. Our findings suggested that modulation of redox homeostasis in the disc can rejuvenate NP cell senescence and thus attenuate disc degeneration.

Moderate-intensity intermittent exercise prevents memory deficit, hippocampal neuron loss, and elevated level of Alzheimer’s dementia markers in the hippocampus of trimethyltin-induced rats

BackgroundModerate-intensity intermittent exercise (MIIE) has been proposed as an effective method for preventing Alzheimer's dementia (AD). AimThis study aimed to investigate the effects of MIIE on the spatial memory and protein level of AD markers in the hippocampus of trimethyltin (TMT)-induced rat model of hippocampal degeneration. MethodsMale Sprague Dawley (SD) rats were randomly assigned into four groups: normal control (N), exercise control (E), TMT control (T), and exercise and TMT (ET). Rats of the exercise groups (E and ET) were forced to run on a treadmill for 30 min each day at maximum for 12 weeks. Intraperitoneal injection of 8 mg/kgBW TMT was administered as a single dose, 10 days before the last exercise treatment for the T and ET groups. The spatial memory of rats was examined using Morris water maze (MWM) test after the exercise period. After euthanasia, the hippocampal tissue was dissected out and the level of hippocampal presenilin-1 (PSEN-1) and phosphorylated tau (p-tau) protein were measured using ELISA. The total number of hippocampal pyramidal neurons was estimated using unbiased stereological analysis. Qualitative immunohistochemistry was performed to examine the expression of brain-derived neurotrophic factor (BDNF), tumor necrosis factor-alpha (TNF-α), and interleukin-10 (IL-10) in paraffin sections of the hippocampus. ResultsTMT exposure induced memory impairment indicated by the T group having the lowest percentage of time and percentage of path length in the target quadrant compared to other groups. MIIE prevented the memory impairment effect of TMT exposure indicated by the ET group having no significantly different MWM performance compared to the E and N groups. The ET group had significantly lower levels of hippocampal AD markers, p-tau and PSEN-1, as well as significantly higher estimated total number of pyramidal neurons of hippocampal CA1 and CA2–3 regions compared to the T group. Expressions of TNF-α was weak, while the expression of IL-10 was stronger in the ET group compared to the control group. The TMT-induced group exhibited stronger expression of BDNF. ConclusionMIIE prevents neuronal loss and impaired spatial memory upon TMT exposure most probably via preventing elevated levels of hippocampal AD markers and neuroinflammation. WC:350.

Nigella sativa-Floral Honey and Multi-Floral Honey versus Nigella sativa Oil against Testicular Degeneration Rat Model: The Possible Protective Mechanisms

The male reproductive function, particularly the testes, and the related hormones are sensitive to various xenobiotics. This work aimed for the first time to assess Nigella sativa floral honey (NS floral honey) and multi-floral honey (M-floral honey) versus Nigella sativa oil (NS oil) against rat testicular degeneration induced with azathioprine (AZA). A total of 40 male Wister rats were assigned into 5 groups: (1) control, (2) 15 mg/kg of AZA, (3) AZA + 1.4 mL/kg of M-floral honey, (4) AZA + 1.4 mL/kg of NS floral honey, and (5) AZA + 500 mg/kg of NA oil. Total testosterone (TT), free testosterone (FT), free androgen index (FAI), gonadotrophins, sex-hormone-binding globulin (SHBG), apoptosis markers, and redox status were assessed to clarify the possible protective mechanisms. Pituitary-testicular axis disruption, apoptosis markers, poor redox status, and sperm quality (count, viability, and motility) were set with AZA. Serum TT, SHBG, and absolute and relative testis weight were significantly restored in the NS oil and NS floral honey groups. Meanwhile, the NS oil group exhibited a significant elevation in FT and FAI. Serum gonadotrophins increased significantly in the NS floral honey (p < 0.01) and M-floral honey and NS oil (p < 0.05) groups. Testicular caspase-3, caspase-9, and nitric oxide showed significant improvement in the NS floral honey and NS oil groups. NS oil supplementation significantly normalized redox status (p < 0.05), whereas NS floral honey improved malondialdehyde and superoxide dismutase activity. Sperm quality exhibited a significant improvement in the NS oil group (p < 0.05). M-floral honey did not show reliable results. Although NS floral honey could protect against testicular damage, it did not upgrade to the level of improvement achieved with NS oil. We claim that further clinical studies are essential for focusing on the quality and quantity of bioactive constituents.

ROS-responsive magnesium-containing microspheres for antioxidative treatment of intervertebral disc degeneration.

Intervertebral disc degeneration (IVDD) is a degenerative disease characterized by lower-back pain, causing disability globally. Antioxidant therapy is currently considered one of the most promising strategies for IVDD treatment, given the crucial role of reactive oxygen species (ROS) in IVDD pathogenesis. Herein, a ROS-responsive magnesium-containing microsphere (Mg@PLPE MS) was constructed for the antioxidative treatment of IVDD. The Mg@PLPE MS has a core-shell structure comprising poly(lactic-co-glycolic acid) (PLGA) and ROS-responsive polymer poly(PBT-co-EGDM) as the shell and a magnesium microparticle as the core. The poly(PBT-co-EGDM) can be destroyed by H2O2 through the H2O2-triggered hydrophobic-to-hydrophilic transition, subsequently promoting an Mg-water reaction to produce H2. Thus, Mg@PLPE MS provides a valuable platform for H2O2 elimination and controlled H2 release. The generated H2 scavenge for ROS by reacting with noxious •OH. Notably, the Mg@PLPE MS exerted significant antioxidative and anti-inflammatory effects in a disc degeneration rat model and alleviated extracellular matrix degradation and disc cells apoptosis, thereby underlining its efficacy in IVDD treatment. The Mg@PLPE MS also exhibited robust biocompatibility and negligible toxicity, presenting the promise for the antioxidative treatment of IVDD in vivo. STATEMENT OF SIGNIFICANCE: Antioxidant therapy is currently considered one of the most promising strategies for intervertebral disc degeneration (IVDD) treatment, given the crucial role of reactive oxygen species (ROS) in IVDD pathogenesis. Here, ROS-responsive magnesium-containing microspheres (Mg@PLPE MSs) were constructed to alleviate IVDD through controlled release of hydrogen gas. The Mg@PLPE MSs can effectively scavenge overproduced ROS by simultaneously reacting with H2O2 and •OH, thus creating a suitable microenvironment for inhibition of ECM degradation. As a result, Mg@PLPE MSs treated IVDD rats exhibit minimal nucleus pulposus decrease, less extracellular matrix degradation, minimal radial fissure of fibrous rings, and higher disc height index. Therefore, the as-prepared Mg@PLPE MSs may shed a new light on clinical treatment of IVDD.

Secondary Degeneration of Oligodendrocyte Precursor Cells Occurs as Early as 24 h after Optic Nerve Injury in Rats.

Optic nerve injury causes secondary degeneration, a sequela that spreads damage from the primary injury to adjacent tissue, through mechanisms such as oxidative stress, apoptosis, and blood-brain barrier (BBB) dysfunction. Oligodendrocyte precursor cells (OPCs), a key component of the BBB and oligodendrogenesis, are vulnerable to oxidative deoxyribonucleic acid (DNA) damage by 3 days post-injury. However, it is unclear whether oxidative damage in OPCs occurs earlier at 1 day post-injury, or whether a critical 'window-of-opportunity' exists for therapeutic intervention. Here, a partial optic nerve transection rat model of secondary degeneration was used with immunohistochemistry to assess BBB dysfunction, oxidative stress, and proliferation in OPCs vulnerable to secondary degeneration. At 1 day post-injury, BBB breach and oxidative DNA damage were observed, alongside increased density of DNA-damaged proliferating cells. DNA-damaged cells underwent apoptosis (cleaved caspase3+), and apoptosis was associated with BBB breach. OPCs experienced DNA damage and apoptosis and were the major proliferating cell type with DNA damage. However, the majority of caspase3+ cells were not OPCs. These results provide novel insights into acute secondary degeneration mechanisms in the optic nerve, highlighting the need to consider early oxidative damage to OPCs in therapeutic efforts to limit degeneration following optic nerve injury.

Augmenting Intracellular Cargo Delivery of Extracellular Vesicles in Hypoxic Tissues through Inhibiting Hypoxia-Induced Endocytic Recycling.

As mesenchymal stem-cell-derived small extracellular vesicles (MSC-sEVs) have been widely applied in treatment of degenerative diseases, it is essential to improve their cargo delivery efficiency in specific microenvironments of lesions. However, the interaction between the microenvironment of recipient cells and MSC-sEVs remains poorly understood. Herein, we find that the cargo delivery efficiency of MSC-sEVs was significantly reduced under hypoxia in inflammaging nucleus pulposus cells due to activated endocytic recycling of MSC-sEVs. Hypoxia-inducible factor-1 (HIF-1)-induced upregulated RCP (also known as RAB11FIP1) is shown to promote the Rab11a-dependent recycling of internalized MSC-sEVs under hypoxia via enhancing the interaction between Rab11a and MSC-sEV. Based on this finding, si-RCP is loaded into MSC-sEVs using electroporation to overcome the hypoxic microenvironment of intervertebral disks. The engineered MSC-sEVs significantly inhibit the endocytic recycling process and exhibit higher delivery efficiency under hypoxia. In a rat model of intervertebral disk degeneration (IDD), the si-RCP-loaded MSC-sEVs successfully treat IDD with improved regenerative capacity compared with natural MSC-sEV. Collectively, the findings illustrate the intracellular traffic mechanism of MSC-sEVs under hypoxia and demonstrate that the therapeutic capacity of MSC-sEVs can be improved via inhibiting endocytic recycling. This modifying strategy may further facilitate the application of extracellular vesicles in hypoxic tissues.

Exosome-laden injectable self-healing hydrogel based on quaternized chitosan and oxidized starch attenuates disc degeneration by suppressing nucleus pulposus senescence

Disc degeneration is the common pathology underlying various degenerative spinal disorders and currently there is no effective cure. Here, we found nucleus pulposus (NP) cell senescence was closely associated with the severity of disc degeneration, and exosomes (Exos) derived from mesenchymal stem cells (MSCs) ameliorated NP cell senescence and promoted extracellular matrix (ECM) deposition. As chitosan-based hydrogels have been widely used as vehicles to deliver Exos due to their prominent antibacterial capacity, biocompatibility, and biodegradability, we developed an Exos-laden hydrogel based on quaternized chitosan (QCS) and oxidized starch (OST) to treat disc degeneration. The synthesized QCS-OST hydrogel is injectable, self-healing, biocompatible, and demonstrated desirable pore size, injectable properties, and sustainable release of Exos. In a rat model of disc degeneration, the QCS-OST/Exos hydrogel was able to rejuvenate NP cell senescence, promote ECM remodeling, and partially restore the structures of NP and annulus fibrosis. Our findings suggested that the novel QCS-OST/Exos hydrogel is an effective therapeutic strategy for treating disc degeneration via alleviating NP cell senescence.