Glycyrrhizic acid ameliorates submandibular gland oxidative stress, autophagy and vascular dysfunction in rat model of type 1 diabetes

Traditional Chinese medicine and its active substances reduce vascular injury in diabetes via regulating autophagic activity

Due to its high prevalence, poor prognosis, and heavy burden on healthcare costs, diabetic vascular complications have become a significant public health issue. Currently, the molecular and pathophysiological mechanisms underlying diabetes-induced vascular complications remain incompletely understood. Autophagy, a highly conserved process of lysosomal degradation, maintains intracellular homeostasis and energy balance via removing protein aggregates, damaged organelles, and exogenous pathogens. Increasing evidence suggests that dysregulated autophagy may contribute to vascular abnormalities in various types of blood vessels, including both microvessels and large vessels, under diabetic conditions. Traditional Chinese medicine (TCM) possesses the characteristics of "multiple components, multiple targets and multiple pathways," and its safety has been demonstrated, particularly with minimal toxicity in liver and kidney. Thus, TCM has gained increasing attention from researchers. Moreover, recent studies have indicated that Chinese herbal medicine and its active compounds can improve vascular damage in diabetes by regulating autophagy. Based on this background, this review summarizes the classification, occurrence process, and related molecular mechanisms of autophagy, with a focus on discussing the role of autophagy in diabetic vascular damage and the protective effects of TCM and its active compounds through the regulation of autophagy in diabetes. Moreover, we systematically elucidate the autophagic mechanisms by which TCM formulations, individual herbal extracts, and active compounds regulate diabetic vascular damage, thereby providing new candidate drugs for clinical treatment of vascular complications in diabetes. Therefore, further exploration of TCM and its active compounds with autophagy-regulating effects holds significant research value for achieving targeted therapeutic approaches for diabetic vascular complications.

Glycyrrhizin regulates antioxidation through Nrf2 signaling pathway in rat temporomandibular joint osteoarthritis

BACKGROUND

Regulation of redox homeostasis could reduce osteoarthritis severity and limit disease progression, while glycyrrhizin (GL) shows great antioxidant and anti-inflammatory capacity.

OBJECTIVE

The aim of this study was to investigate the role of GL on oxidative stress and the potential regulatory mechanism in rat temporomandibular joint (TMJ) chondrocytes under oxidative stress, and investigate the effect of GL in the rat temporomandibular joint osteoarthritis (TMJOA) model.

METHODS

Rat TMJ chondrocytes were cultured in oxidative stress with different doses of GL. The effect of glycyrrhizin on the nuclear factor-erythroid 2-related factor 2 (Nrf2) in oxidative stress was evaluated by western blot and immunofluorescence staining. A rat model of TMJOA was treated with GL. Micro-computed tomography, histological and immunohistochemical analysis were used to assess the pathological change of TMJOA.

RESULTS

The expression of superoxide dismutase 1 (SOD1), heme oxygenase-1 (HO-1), and peroxiredoxin 6 (PRDX6) were decreased, and intracellular Nrf2 signaling pathway was activated in chondrocytes in oxidative stress. GL upregulates the expression of antioxidants, especially PRDX6, as well as increases Nrf2 expression and nuclear translocation in rat condylar chondrocytes. Administration of GL attenuates condylar bone destruction, cartilage degeneration, and synovitis in rats TMJOA. Meanwhile, GL alleviated oxidative stress and enhanced the antioxidant capacity of TMJOA cartilage.

CONCLUSION

This study suggested that GL alleviates rat TMJOA by regulating oxidative stress in condylar cartilage.

Glycyrrhizin alleviates radiation-induced lung injury by regulating the NLRP3 inflammasome through endoplasmic reticulum stress

Objective

Radiation pneumonitis (RP) is the major adverse response of radiation therapy for thoracic malignant tumors, and there is a lack of effective interventions. The aim of this study was to investigate the radioprotective effect of Glycyrrhizin (GL) on RP and its potential mechanism.

Method

The body weight and lung weight of mice were monitored. HE staining was used to observe lung injury, and the expression of endoplasmic reticulum (ER) stress biomarkers and the activation of NLRP3 inflammasome were determined by Western blotting and immunohistochemistry. Flow cytometry was performed to check MLE-12 apoptosis. ER stress activator, Tunicamycin (Tuni), was used to verify the potential mechanism of GL. A systemic pharmacology explored the potential targets and pathways of GL.

Results

In this study, the lungs of irradiated mice showed significant pneumonic changes. In vivo and in vitro assay, NLRP3 inflammasome was significantly activated, the expression of ER stress biomarkers was elevated, flow cytometry confirms increased apoptosis in irradiated MLE-12 cells. GL inhibits the activation of NLRP3 inflammasome and ER stress pathways. Furthermore, systemic pharmacology revealed that the radioprotective effect of GL may be related to the MAPK signaling pathway.

Conclusion

In the present study, the results indicated that GL may regulate NLRP3 inflammasome through ER stress, thus exerting irradiation-protective effects on RP, and the ER stress pathway may be a potential target for RP treatment.

Assessment of redox state and biochemical parameters of salivary glands in streptozotocin-induced diabetic male rats treated with mate tea (Ilex paraguariensis)

OBJECTIVE

The study aimed to assess the effects of mate tea [Ilex paraguariensis] on the redox state and biochemical parameters of salivary glands in diabetic male rats.

DESIGN

Twenty-four male Wistar rats (3 months old) were randomly divided into groups (n = 8 per group): control rats that received water (C); diabetic rats that received water (D); diabetic rats treated with mate tea (DMT). The treated streptozotocin-induced diabetic rats were given mate tea powder by intragastric gavage at a dose of 20 mg/kg daily for 28 days. Content of total protein, amylase, oxidative lipid damage, measured as thiobarbituric acid reactive substances (TBARs), oxidative protein damage, measured as protein carbonyl, total antioxidant capacity, uric acid, reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were examined by the spectrophotometric method in the parotid and submandibular glands.

RESULTS

The D group showed lower total protein, amylase, TBARs, protein carbonyl, total antioxidant capacity, GSH, uric acid, and GPx than the C group in both salivary glands, as well as higher SOD and CAT activities. The DMT group showed higher total protein, amylase, total antioxidant capacity, GSH, uric acid, and GPx than the D group in both salivary glands. Moreover, mate tea increased SOD in the parotid gland and CAT in the submandibular gland of diabetic rats but did not influence TBARs and protein carbonyl in either salivary gland compared to D group.

CONCLUSION

Mate tea increased tissue protein synthesis and improved antioxidant defenses in the salivary glands of streptozotocin-induced diabetic male rats.

Sepsis-induced AKI: From pathogenesis to therapeutic approaches

Sepsis is a heterogenous and highly complex clinical syndrome, which is caused by infectious or noninfectious factors. Acute kidney injury (AKI) is one of the most common and severe complication of sepsis, and it is associated with high mortality and poor outcomes. Recent evidence has identified that autophagy participates in the pathophysiology of sepsis-associated AKI. Despite the use of antibiotics, the mortality rate is still at an extremely high level in patients with sepsis. Besides traditional treatments, many natural products, including phytochemicals and their derivatives, are proved to exert protective effects through multiple mechanisms, such as regulation of autophagy, inhibition of inflammation, fibrosis, and apoptosis, etc. Accumulating evidence has also shown that many pharmacological inhibitors might have potential therapeutic effects in sepsis-induced AKI. Hence, understanding the pathophysiology of sepsis-induced AKI may help to develop novel therapeutics to attenuate the complications of sepsis and lower the mortality rate. This review updates the recent progress of underlying pathophysiological mechanisms of sepsis-associated AKI, focuses specifically on autophagy, and summarizes the potential therapeutic effects of phytochemicals and pharmacological inhibitors.

Role of Dapagliflozin and Liraglutide on Diabetes-Induced Cardiomyopathy in Rats: Implication of Oxidative Stress, Inflammation, and Apoptosis

The current study aims to assess the protective effects of dapagliflozin (Dapa; a sodium-glucose cotransporter-2 inhibitor) and/or liraglutide (Lira; a glucagon-like peptide 1 agonist) in an experimental model of diabetic cardiomyopathy (DCM). A single dose of streptozotocin (STZ) was administrated to male Sprague-Dawley rats by intraperitoneal injection at a dose of 50 mg/kg to induce diabetes mellitus (DM). Dapa (1 mg/kg, orally), Lira (0.4 mg/kg, s.c.), and Dapa-Lira combination were administrated for 8 weeks once-daily. Blood samples were evaluated for glucose level and biochemical markers of cardiac functions. Cardiac tissue was dissected and assessed for redox homeostasis (malondialdehyde (MDA), glutathione (GSH), and catalase (CAT)), pro-inflammatory mediators (NF-κB and tumor necrosis factor-α (TNF-α)), and apoptotic effectors (caspase-3). Moreover, the effect of treatments on the cardiac cellular structure was studied. Dapa and/or Lira administration resulted in significant improvement of biochemical indices of cardiac function. Additionally, all treatment groups demonstrated restoration of oxidant/antioxidant balance. Moreover, inflammation and apoptosis key elements were markedly downregulated in cardiac tissue. Also, histological studies demonstrated attenuation of diabetes-induced cardiac tissue injury. Interestingly, Dapa-Lira combination treatment produced a more favorable protective effect as compared to a single treatment. These data demonstrated that Dapa, Lira, and their combination therapy could be useful in protection against DM-accompanied cardiac tissue injury, shedding the light on their possible utilization as adjuvant therapy for the management of DM patients.