Daily Low-intensity Pulsed Ultrasound Ameliorates Renal Fibrosis and Inflammation in Experimental Hypertensive and Diabetic Nephropathy

Low-intensity pulsed ultrasound improves metabolic dysregulation in obese mice by suppressing inflammation and extracellular matrix remodeling

Chronic inflammation in white adipose tissue is crucial in obesity and related metabolic disorders. Low-intensity pulsed ultrasound (LIPUS) is renowned for its anti-inflammatory effects as a non-invasive treatment, yet its precise role in obesity has been uncertain. Our study investigates the therapeutic effect of LIPUS and its underlying mechanism on obesity in mice, thereby offering a novel approach for non-invasive treatment of obesity and associated metabolic disorders for human. Male C57BL/6J mice aged 10 weeks were fed a high-fat diet (HFD) for 8 weeks to establish obesity model, then underwent 8 weeks of LIPUS (frequency: 1.0 MHz, duty cycle: 20 %, Isata: 58-61 mW/cm2, 20 min per day) stimulation of the epididymal white adipose tissue. Fat and lean mass were measured using nuclear magnetic resonance (NMR), while energy homeostasis was evaluated using metabolic cages. Insulin resistance was assessed using glucose tolerance tests (GTT) and insulin tolerance tests (ITT). Regulatory mechanisms were explored using RNA sequencing. Results showed that LIPUS significantly reduced obesity markers in obese mice, including body and adipose tissue weight, and improved insulin resistance, without affecting food intake. RNA sequencing showed 250 up-regulated and 351 down-regulated genes between HFD-LIPUS group and HFD-Sham group, suggesting anti-inflammatory action. Quantitative PCR confirmed reduced pro-inflammatory gene expression and macrophage infiltration in eWAT. Gene set enrichment analysis showed decreased NF-κB signaling and extracellular matrix-receptor interactions in LIPUS-treated mice. Thus, LIPUS effectively mitigates metabolic dysregulation in HFD-induced obesity through inflammation suppression and extracellular matrix remodeling, which provides a potential physical therapy for metabolic syndrome in clinic.

Current perspectives and trends of the research on hypertensive nephropathy: a bibliometric analysis from 2000 to 2023

Hypertensive nephropathy continues to be a major cause of end-stage renal disease and poses a significant global health burden. Despite the staggering development of research in hypertensive nephropathy, scientists and clinicians can only seek out useful information through articles and reviews, it remains a hurdle for them to quickly track the trend in this field. This study uses the bibliometric method to identify the evolutionary development and recent hotspots of hypertensive nephropathy. The Web of Science Core Collection database was used to extract publications on hypertensive nephropathy from January 2000 to November 2023. CiteSpace was used to capture the patterns and trends from multi-perspectives, including countries/regions, institutions, keywords, and references. In total, 557 publications on hypertensive nephropathy were eligible for inclusion. China (n = 208, 37.34%) was the most influential contributor among all the countries. Veterans Health Administration (n = 19, 3.41%) was found to be the most productive institution. Keyword bursting till now are renal fibrosis, outcomes, and mechanisms which are predicted to be the potential frontiers and hotspots in the future. The top seven references were listed, and their burst strength was shown. A comprehensive overview of the current status and research frontiers of hypertensive nephropathy has been provided through the bibliometric perspective. Recent advancements and challenges in hypertensive nephropathy have been discussed. These findings can offer informative instructions for researchers and scholars.

Salidroside Pre-Treatment Inhibits Hypertensive Renal Injury and Fibrosis Through Inhibiting Wnt/β-Catenin Pathway

Objectives

This study aimed to explore the protective effects and underlying mechanisms of salidroside (SAL) in angiotensin II (Ang II)-induced hypertensive renal injury and fibrosis, using in vivo and in vitro models.

Methods

In this study, we generated Ang II-induced hypertensive renal injury and fibrosis in mice and the recombinant interferon-gamma (IFN-γ)-stimulated murine podocyte clone 5 (MPC5) model in vitro. Histological and oxidative stress analyses were performed to evaluate the renal injury.

Results

SAL pre-treatment reduced systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and attenuated serum creatinine (Scr), blood urea nitrogen (BUN), and serum cystatin C (Cys-C) levels in Ang II-infused mice (all, P < 0.001). SAL reduced renal fibrosis and related molecules expression, including Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) (all, P < 0.001). SAL decreased the content of malondialdehyde (MDA) while increasing superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in Ang II-treated mice (all, P < 0.001). In addition, SAL pre-treatment inhibited AT1R, Wnt1, Wnt3a, and β-catenin expressions (all, P < 0.001), both in vivo and in vitro.

Conclusion

Our experimental data demonstrate that SAL pre-treatment protects against Ang II-induced hypertensive renal injury and fibrosis by suppressing the Wnt/β-catenin pathway in vivo and in vitro.

BRD4: an effective target for organ fibrosis

Fibrosis is an excessive wound-healing response induced by repeated or chronic external stimuli to tissues, significantly impacting quality of life and primarily contributing to organ failure. Organ fibrosis is reported to cause 45% of all-cause mortality worldwide. Despite extensive efforts to develop new antifibrotic drugs, drug discovery has not kept pace with the clinical demand. Currently, only pirfenidone and nintedanib are approved by the FDA to treat pulmonary fibrotic illness, whereas there are currently no available antifibrotic drugs for hepatic, cardiac or renal fibrosis. The development of fibrosis is closely related to epigenetic alterations. The field of epigenetics primarily studies biological processes, including chromatin modifications, epigenetic readers, DNA transcription and RNA translation. The bromodomain and extra-terminal structural domain (BET) family, a class of epigenetic readers, specifically recognizes acetylated histone lysine residues and promotes the formation of transcriptional complexes. Bromodomain-containing protein 4 (BRD4) is one of the most well-researched proteins in the BET family. BRD4 is implicated in the expression of genes related to inflammation and pro-fibrosis during fibrosis. Inhibition of BRD4 has shown promising anti-fibrotic effects in preclinical studies; however, no BRD4 inhibitor has been approved for clinical use. This review introduces the structure and function of BET proteins, the research progress on BRD4 in organ fibrosis, and the inhibitors of BRD4 utilized in fibrosis. We emphasize the feasibility of targeting BRD4 as an anti-fibrotic strategy and discuss the therapeutic potential and challenges associated with BRD4 inhibitors in treating fibrotic diseases.

Low-Intensity Pulsed Ultrasound: A Physical Stimulus with Immunomodulatory and Anti-inflammatory Potential

Ultrasound has expanded into the therapeutic field as a medical imaging and diagnostic technique. Low-intensity pulsed ultrasound (LIPUS) is a kind of therapeutic ultrasound that plays a vital role in promoting fracture healing, wound repair, immunomodulation, and reducing inflammation. Its anti-inflammatory effects are manifested by decreased pro-inflammatory cytokines and chemokines, accelerated regression of immune cell invasion, and accelerated damage repair. Although the anti-inflammatory mechanism of LIPUS is not very clear, many in vitro and in vivo studies have shown that LIPUS may play its anti-inflammatory role by activating signaling pathways such as integrin/Focal adhesion kinase (FAK)/Phosphatidylinositol 3-kinase (PI3K)/Serine threonine kinase (Akt), Vascular endothelial growth factor (VEGF)/endothelial nitric oxide synthase (eNOS), or inhibiting signaling pathways such as Toll-like receptors (TLRs)/Nuclear factor kappa-B (NF-κB) and p38-Mitogen-activated protein kinase (MAPK). As a non-invasive physical therapy, the anti-inflammatory and immunomodulatory effects of LIPUS deserve further exploration.

Effects of Neuromuscular Electrical Stimulation and Therapeutic Ultrasound on Quadriceps Contracture of Immobilized Rats

Quadriceps contracture is a condition where the muscle-tendon unit is abnormally shortened. The treatment prognosis is guarded to poor depending on the progress of the disease. To improve the prognosis, we investigated the effectiveness of therapeutic ultrasound and NMES in treating quadriceps contracture in an immobilized rat model. Thirty-six Wistar rats were randomized into control, immobilization alone, immobilization and spontaneous recovery, immobilization and therapeutic ultrasound, immobilization and NMES, and immobilization and therapeutic ultrasound and NMES combination groups. The continuous therapeutic ultrasound (frequency, 3 MHz, intensity 1 W/cm2) and NMES (TENS mode, frequency 50 Hz; intensity 5.0 ± 0.8 mA) were performed on the quadriceps muscle. On Day 15, immobilization-induced quadriceps contracture resulted in a decreased ROM of the stifle joint, reduction in the sarcomere length, muscle atrophy, and muscle fibrosis. On Day 43, therapeutic ultrasound, NMES, and combining both methods improved muscle atrophy and shortening and decreased collagen type I and III and α-SMA protein. The combination of therapeutic ultrasound and NMES significantly reduced the mRNA expression of IL-1β, TGF-β1, and HIF-1α and increased TGF-β3. Therefore, the combination of therapeutic ultrasound and NMES is the most potent rehabilitation program for treating quadriceps contracture.

Research trends and perspective of low-intensity pulsed ultrasound in orthopedic rehabilitation treatment based on Web of Science: A bibliometric analysis

BACKGROUND

Ultrasound has a long history as a diagnostic and therapeutic tool. Low-intensity pulsed ultrasound (LIPUS), whose intensity is below 300 mW/cm2, has been widely used in orthopedic rehabilitation treatment. However, the detailed bioeffects and underlying mechanisms of LIPUS treatment need to be explored.

OBJECTIVE

To make a comprehensive view of the field, bibliometric and visualization analysis was used to reveal the global research trends of LIPUS in orthopedics and rehabilitation treatment between 1994 and 2023.

METHODS

All literature data on LIPUS were retrieved from the Web of Science Core Collection database. VOSviewer and CiteSpace were applied for the bibliometric and visualization analysis.

RESULTS

A total of 760 publications were included. The distribution of publications generally showed an unstable rising trend. China had the highest number of publications (28.0%), and Chong Qing Medical University was the organization with the highest number of publications (5.8%). Ultrasound in Medicine and Biology had the highest number of publications (8.8%), while BMJ-British Medical Journal had the highest impact factor among the retrieved journals. Ling Qin from the Chinese University of Hong Kong was the most active researcher. Our overlay visualization map showed that the keywords such as pain, knee osteoarthritis, apoptosis, chondrocytes, cartilage, and autophagy, which link to osteoarthritis, have becoming the new research trends and hotspots.

CONCLUSION

LIPUS is a popular and increasingly important area of orthopedic rehabilitation, and collaboration of authors from different countries should be further strengthened. Predictably, clinical application of LIPUS on chronic inflammation-related diseases and regenerative medicine, and in-depth biological mechanisms are the orientations of LIPUS in orthopedic rehabilitation treatment.

LIPUS Alleviates Knee Joint Capsule Fibrosis in Rabbits by Regulating SOD/ROS Dynamics and Inhibiting the TGF-β1/Smad Signaling Pathway

OBJECTIVE

The aim of the work described here was to investigate the efficacy and potential mechanisms of low-intensity pulsed ultrasound (LIPUS) for the treatment of arthrogenic contracture induced by immobilization in rabbits.

METHODS

The left knee joint of rabbits was immobilized for 6 wk to establish the model of extending knee joint contracture. The rabbits were divided into a control group (C), a group immobilized for 6 wk (IM-6w), a group remobilized for 1 wk (RM-1w), a group subjected to LIPUS intervention for 1 wk (LIPUS-1w), a group remobilized for 2 wk (RM-2w) and a group subjected to LIPUS intervention for 2 wk (LIPUS-2w). The degrees of arthrogenic contracture and joint capsule fibrosis were assessed, as were the levels of reactive oxygen species (ROS) and the activation status of the TGF-β1/Smad signaling pathway in the joint capsule.

RESULTS

After immobilization for 6 wk, the degrees of arthrogenic contracture and joint capsule fibrosis increased. The ROS level increased, as evidenced by an increase in malondialdehyde content and a decrease in superoxide dismutase content. In addition, the TGF-β1/Smad signaling pathway was significantly activated. The degrees of knee joint contracture increased in the first week after remobilization and decreased in the second week. Furthermore, joint capsule fibrosis continued to develop during the 2 wk of remobilization, and the ROS level increased, while the TGF-β1/Smad signaling pathway was significantly activated. LIPUS effectively reduced the level of ROS in the joint capsule, which further inhibited activation of the TGF-β1/Smad signaling pathway, thereby improving joint capsule fibrosis and reducing arthrogenic contracture.

CONCLUSION

The high ROS levels and overactivation of the TGF-β1/Smad signaling pathway may be reasons why immobilization induces knee joint capsule fibrosis. LIPUS can alleviate the degree of knee joint capsule fibrosis induced by immobilization by inhibiting the production of ROS and the activation of the TGF-β1/Smad signaling pathway.

Low intensity pulsed ultrasound ameliorates Adriamycin-induced chronic renal injury by inhibiting ferroptosis

OBJECTIVE

It is very important to develop a new therapeutic strategy to cope with the increasing morbidity and mortality of chronic kidney disease (CKD). As a kind of physical therapy, low intensity pulsed ultrasound (LIPUS) has remarkable anti-inflammatory and repair-promoting effects and is expected to become a new therapeutic method for CKD. This study aims to clarify the treatment effect of LIPUS on CKD-related renal inflammation and fibrosis, and to further explore the potential signal network of LIPUS treatment for ameliorating chronic renal injury.

METHODS

A rat model simulating the progress of CKD was established by twice tail-vein injection of Adriamycin (ADR). Under anesthesia, bilateral kidneys of CKD rats were continuously stimulated by LIPUS for four weeks. The parameters of LIPUS were 1.0 MHz, 60 mW/cm2, 50% duty cycle and 20 min/d.

RESULTS

LIPUS treatment effectively inhibited ADR-induced renal inflammation and fibrosis, and improved CKD-related to oxidative stress and ferroptosis. In addition, the therapeutic effect of LIPUS is closely related to the regulation of TGF-β1/Smad and Nrf2/keap1/HO-1 signalling pathways.

DISCUSSION

This study provides a new direction for further mechanism research and lays an important foundation for clinical trials.

Therapeutic Myogenesis Induced by Ultrasound Exposure in a Volumetric Skeletal Muscle Loss Injury Model

BACKGROUND

Low-intensity pulsed ultrasound (LIPUS) irradiation has been shown to induce various responses in different cells. It has been shown that LIPUS activates extracellular signal-regulated kinase 1/2 (ERK1/2) through integrin.

PURPOSE

To study the effects of LIPUS on myogenic regulatory factors and other related myogenesis elements in a volumetric skeletal muscle loss injury model.

STUDY DESIGN

Controlled laboratory study.

METHODS

C57BL/6J mice were subjected to full-thickness muscle defect injury of the quadriceps and treated with direct application of LIPUS 20 min/d or non-LIPUS treatment (control) for 3, 7, and 14 days. LIPUS was also applied to C2C12 cells in culture in the presence of low and high doses of lipopolysaccharides. The expression levels of myogenic regulatory factors and the expression levels of myokine-related and angiogenic-related proteins of the control and LIPUS groups were analyzed.

RESULTS

Muscle volume in the injury site was restored at day 14 with LIPUS treatment. Paired-box protein 7, myogenic factor 5, myogenin, and desmin expressions were significantly different between control and LIPUS groups at days 7 and 14. Myokine and angiogenic cytokine-related factors were significantly increased in the LIPUS group at day 3 and decreased with no significant difference between the groups by day 14. LIPUS induced different responses of myogenic regulatory factors in C2C12 cells with low and high doses of lipopolysaccharides. LIPUS promoted myogenesis through short-lived increase in interleukin-6 and heme oxygenase 1, together with activation of ERK1/2.

CONCLUSION

LIPUS had a constant effect on the variables of tissue damage, from macrotrauma to microtrauma, leading to efficient muscle regeneration.

CLINICAL RELEVANCE

The focus of therapeutic strategies with LIPUS has been not only for microvascular regeneration but also for skeletal muscle and related local tissue recovery from acute or chronic damage.

Transcriptome profile analysis revealed the potential mechanism of LIPUS treatment for Adriamycin-induced chronic kidney disease rat

Background

Developing effective therapeutic strategies to delay the progression of chronic kidney disease (CKD) remains a significant challenge. Low-intensity pulsed ultrasound (LIPUS) has demonstrated potential for treating CKD, but the underlying molecular mechanisms are still elusive. This study aimed to evaluate the therapeutic efficacy of LIPUS and to elucidate the involved genes and signaling pathways.

Methods

The CKD model was established in rats using Adriamycin (ADR). The bilateral kidneys of CKD rats were continuously stimulated with LIPUS for a period of four weeks. The therapeutic efficacy was defined by renal function and histopathological evaluation. RNA sequencing was employed to profile the transcriptome of rat kidneys in each group. Cluster analysis was utilized to identify differentially expressed genes (DEGs), followed by enrichment analysis of their associated pathways using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases.

Results

LIPUS treatment improved ADR-induced renal dysfunction in the CKD group. Renal fibrosis and pathological damages were also alleviated in the ADR + LIPUS group compared to the ADR group. Cluster analysis identified 844 DEGs. GO enrichment analysis revealed enrichment in inflammatory response terms, while KEGG enrichment analysis highlighted the nuclear factor kappa B (NF-κB) signaling and ferroptosis-related pathways.

Conclusion

Continuous LIPUS treatment improved ADR-induced renal fibrosis and dysfunction. The therapeutic effect of LIPUS was primarily due to its ability to suppress the CKD-related inflammation, which was associated with the modulation of the NF-κB and ferroptosis signaling pathways. These findings provide a new insight into the potential molecular mechanisms of LIPUS in treating CKD. Further research is necessary to confirm these findings and to identify potential therapeutic targets within these pathways.

Translation Animal Models of Diabetic Kidney Disease: Biochemical and Histological Phenotypes, Advantages and Limitations

Animal models play a crucial role in studying the pathogenesis of diseases, developing new drugs, identifying disease risk markers, and improving means of prevention and treatment. However, modeling diabetic kidney disease (DKD) has posed a challenge for scientists. Although numerous models have been successfully developed, none of them can encompass all the key characteristics of human DKD. It is essential to choose the appropriate model according to the research needs, as different models develop different phenotypes and have their limitations. This paper provides a comprehensive overview of biochemical and histological phenotypes, modeling mechanisms, advantages and limitations of DKD animal models, in order to update relevant model information and provide insights and references for generating or selecting the appropriate animal models to fit different experimental needs.

The sustainable antihypertensive and target organ damage protective effect of transcranial focused ultrasound stimulation in spontaneously hypertensive rats

OBJECTIVE

In this study, we aimed to investigate the sustainable antihypertensive effects and protection against target organ damage caused by low-intensity focused ultrasound (LIFU) stimulation and the underlying mechanism in spontaneously hypertensive rats (SHRs) model.

METHODS AND RESULTS

SHRs were treated with ultrasound stimulation of the ventrolateral periaqueductal gray (VlPAG) for 20 min every day for 2 months. Systolic blood pressure (SBP) was compared among normotensive Wistar-Kyoto rats, SHR control group, SHR Sham group, and SHR LIFU stimulation group. Cardiac ultrasound imaging and hematoxylin-eosin and Masson staining of the heart and kidney were performed to assess target organ damage. The c-fos immunofluorescence analysis and plasma levels of angiotensin II, aldosterone, hydrocortisone, and endothelin-1 were measured to investigate the neurohumoral and organ systems involved. We found that SBP was reduced from 172 ± 4.2 mmHg to 141 ± 2.1 mmHg after 1 month of LIFU stimulation, P  < 0.01. The next month of treatment can maintain the rat's blood pressure at 146 ± 4.2 mmHg at the end of the experiment. LIFU stimulation reverses left ventricular hypertrophy and improves heart and kidney function. Furthermore, LIFU stimulation enhanced the neural activity from the VLPAG to the caudal ventrolateral medulla and reduced the plasma levels of ANGII and Aldo.

CONCLUSION

We concluded that LIFU stimulation has a sustainable antihypertensive effect and protects against target organ damage by activating antihypertensive neural pathways from VLPAG to the caudal ventrolateral medulla and further inhibiting the renin-angiotensin system (RAS) activity, thereby supporting a novel and noninvasive alternative therapy to treat hypertension.

Design and characteristic analysis of flexible CNT film patch for potential application in ultrasonic therapy

Ultrasonic therapy has drawn increasing attention due to its noninvasiveness, great sensitivity and strong penetration capabilities. However, most of traditional rigid ultrasonic probes cannot achieve a solid interfacial contact with irregular nonplanar surfaces, which leads to unstable therapeutic effects and limitations of widespread use in practical applications. In this paper, a new flexible ultrasonic patch based on carbon nanotube (CNT) films is designed and fabricated to achieve a potential application in ultrasonic therapy. This patch is composed of a CNT film, a thermal protective layer and a heat sinking layer, and has the advantages of simple structure, soft, ultrathin and completely conforming to the treatment area. Theoretical and experimental studies are performed to investigate the acoustic and temperature fields before and after deformation. Effects of key design parameters of the patch on acoustic performances and temperature distributions are revealed. Numerical results indicate that the CNT film patch can produce ultrasounds over a wide frequency range and temperatures under the threshold of burn injury whether it is bent or not. Furthermore, it is also noted that the sound waves emitted from the bending patch are focused at the center of the bending patch, which demonstrates that the target treatment area can be controlled.

Low-intensity pulsed ultrasound enhances bone marrow-derived stem cells-based periodontal regenerative therapies

BACKGROUND

Alveolar bone loss is one of the most common consequence for periodontitis, which is a major obstacle in periodontal regeneration. Bone marrow stromal cells (BMSCs) have shown significant promise in the treatment of various disease, which also contribute to the natural bone repair process. Low-intensity pulsed ultrasound (LIPUS) is a therapeutic ultrasound used in our previous studies to promotes alveolar bone regeneration. In addition, LIPUS was found to be a promising method to enhance mesenchymal stromal cell-based therapies. In the current study, we have investigated the effects of LIPUS combined with BMSCs therapies on BMSCs homing and its potential to promote alveolar bone regeneration.

METHODS

BMSCs were isolated from rat and characterized by multilineages differentiation assay. Then these cells were labeled with luciferase and green fluorescent protein (GFP) by lentivirus in vitro. Periodontal bone defect was made on the mesial area of the maxillary first molar in rats. A total of 1 × 10⁶ Luc-GFP labeled BMSCs were injected into rat tail vein. Bioluminescence imaging was utilized to track BMSCs in vivo. The rats were sacrificed eight weeks after surgery and the samples were harvested. Micro-computed tomography (Micro-CT) was performed to evaluate alveolar bone regeneration. Paraffin sections were made and subject to hematoxylin-eosin staining, masson staining and immunohistochemistry staining.

RESULTS

BMSCs display a fibroblast-like morphology and can differentiate into adipocytes or osteoblasts under appropriate condition. The transfected BMSCs are strongly positive for GFP express. Bioluminescence imaging showed that most of BMSCs were trapped in the lung. A small portion BMSCs were homed to the alveolar bone defect area in BMSCs group, while more cells were observed in BMSCs/LIPUS group compare to other groups on day 3 and 7. Micro-CT results showed that BMSCs/LIPUS group resulted in more new bone formation than other groups. Immunohistochemical results showed higher expression of COL-I and osteopontin in BMSCs/LIPUS group compared with the other groups.

CONCLUSIONS

These results suggested that LIPUS can enhance BMSCs-based periodontal alveolar bone regeneration. This study provides new insights into how LIPUS might provide therapeutic benefits by promoting BMSCs homing.

Cordyceps cicadae Ameliorates Renal Hypertensive Injury and Fibrosis Through the Regulation of SIRT1-Mediated Autophagy

Hypertensive renal injury is a complication of hypertension. Cordyceps cicadae (C. cicadae) is a traditional Chinese medicine used to treat chronic kidney diseases especially renal fibrosis. Autophagy is described as a cell self-renewal process that requires lysosomal degradation and is utilized for the maintenance of cellular energy homeostasis. The present study explores the mechanism underlying C. cicadae’s renoprotection on hypertensive nephropathy (HN). First, HN rat models were established on spontaneously hypertensive rats (SHRs). The expression of fibrosis-related protein and autophagy-associated protein was detected in vivo. NRK-52E cells exposed to AngII were chosen to observe the potential health benefits of C. cicadae on renal damage. The level of extracellular matrix accumulation was detected using capillary electrophoresis immunoquantification and immunohistochemistry. After treatment with lysosomal inhibitors (chloroquine) or an autophagy activator (rapamycin), the expression of Beclin-1, LC3II, and SQSTM1/p62 was further investigated. The study also investigated the change in sirtuin1 (SIRT1), fork head box O3a (FOXO3a), and peroxidation (superoxide dismutase (SOD) and malondialdehyde (MDA)) expression when intervened by resveratrol. The changes in SIRT1 and FOXO3a were measured in patients and the SHRs. Here, we observed that C. cicadae significantly decreased damage to renal tubular epithelial cells and TGFβ1, α-smooth muscle actin (α-SMA), collagen I (Col-1), and fibronectin expression. Meanwhile, autophagy defects were observed both in vivo and in vitro. C. cicadae intervention significantly downregulated Beclin-1 and LC3II and decreased SQSTM1/p62, showing an inhibition of autophagic vesicles and the alleviation of autophagy stress. These functions were suppressed by rapamycin, and the results were just as effective as the resveratrol treatment. HN patients and the SHRs exhibited decreased levels of SIRT1 and FOXO3a. We also observed a positive correlation between SIRT1/FOXO3a and antifibrotic effects. Similar to the resveratrol group, the expression of SIRT1/FOXO3a and oxidative stress were elevated by C. cicadae in vivo. Taken together, our findings show that C. cicadae ameliorates tubulointerstitial fibrosis and delays HN progression. Renoprotection was likely attributable to the regulation of autophagic stress mediated by the SIRT1 pathway and achieved by regulating FOXO3a and oxidative stress.

Neuroimmune system-mediated renal protection mechanisms

The autonomic nervous system plays an important role in maintaining homeostasis in organisms. Recent studies have shown that it also controls inflammation by directly altering the function of the immune system. The cholinergic anti-inflammatory pathway (CAP) is one of the neural circuits operating through the vagus nerve. Acetylcholine released from the terminal of the vagus nerve, which is a parasympathetic nerve, acts on the α7 nicotinic acetylcholine receptor of macrophages and reduces inflammation in the body. Previous animal studies demonstrated that vagus nerve stimulation reduced renal ischemia-reperfusion injury. Furthermore, restraint stress and pulsed ultrasound had similar protective effects against kidney injury, which were mainly thought to be mediated by the CAP. Using optogenetics, which can stimulate specific nerves, it was also revealed that activation of the CAP by restraint stress was mediated by C1 neurons in the medulla oblongata. Nevertheless, there still remain many unclear points regarding the role of the nervous and immune systems in controlling renal diseases, and further research is needed.