Haixia Zhao

Chikusetsu saponin V attenuates H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells through Sirt1/PGC-1α/Mn-SOD signaling pathways

Oxidative stress plays a vital role in the pathogenesis of neurodegenerative diseases. Chikusetsu saponin V (CsV), the most abundant member of saponins from Panax japonicus (SPJ), has attracted increasing attention for its potential to treat neurodegenerative diseases. However, the mechanisms are unclear. Our study intended to investigate the antioxidative effects of CsV in human neuroblastoma SH-SY5Y cells. Our data showed that CsV attenuated H2O2-induced cytotoxicity, inhibited ROS accumulation, increased the activities of superoxide dismutase (SOD) and GSH, and increased mitochondrial membrane potential dose-dependently. Further exploration of the mechanisms showed that CsV exhibited these effects through increasing the activation of oxidative-stress-associated factors including Sirt1, PGC-1α, and Mn-SOD. Moreover, CsV inhibited H2O2-induced down-regulation of Bcl-2 and up-regulation of Bax in a dose-dependent manner and, thus, increased the ratio of Bcl-2/Bax. In conclusion, our study demonstrated that CsV exhibited neuroprotective effects possibly through Sirt1/PGC-1α/Mn-SOD signaling pathways.

Chikusetsu saponin IVa ameliorates high fat diet-induced inflammation in adipose tissue of mice through inhibition of NLRP3 inflammasome activation and NF-κB signaling

Chronic metabolic inflammation in adipose tissue plays an important role in the development of obesity-associated diseases. Our previous study indicated that total saponins of Panax japonicus (SPJ) rhizoma and Chikusetsu saponin V, one main component of SPJ, could exert the anti-oxidative and anti-inflammatory effects. The present study aimed to investigate the in vivo and Ex vivo anti-inflammatory activities of another main component of SPJ, namely Chikusetsu saponin IVa (CS). CS could significantly inhibited HFD-induced lipid homeostasis, and inhibited inflammation in adipose tissue, as reflected by the decreased mRNA expression levels of inflammation-related genes and secretion of the chemokines/cytokines, inhibited the accumulation of adipose tissue macrophages (ATMs) and shifted their polarization from M1 to M2, suppressed HFD-induced expression of NLRP3 inflammasome component genes and decreased IL-1β and Caspase-1 production in mice. Moreover, CS treatment also inhibited the activation of NLRP3 inflammasome in bone marrow-derived macrophages (BMDMs). Meanwhile, CS treatment inhibited an NLRP3-induced ASC pyroptosome formation and lipopolysaccharide (LPS)-induced pyroptosis. Furthermore, CS treatment suppressed HFD-induced NF-κB signaling in vivo and LPS-induced NF-κB activation as reflected by the fact that their phosphorylated forms and the ratios of pNF-κB/NF-κB, pIKK/IKK, and pIκB/IκB were all decreased in EAT from HFD-fed mice treated with CS as compared with those of HFD mice. Taking together, this study has revealed that CS effectively inhibits HFD-induced inflammation in adipose tissue of mice through inhibiting both NLRP3 inflammasome activation and NF-κB signaling. Thus, CS can serve as a potential therapeutic drug in the prevention and treatment of inflammation-associated diseases.

Vaccine adjuvant ginsenoside Rg1 enhances immune responses against hepatitis B surface antigen in mice

The adjuvant effect of ginsenoside Rg1 on immune responses against hepatitis B surface antigen (HBsAg) in mice was investigated. Female BALB/c mice were subcutaneously injected with saline or HBsAg antigen with or without Rg1 on days 7 and 21. Samples were collected 2 weeks after the boosting for the detection of anti-HBsAg immunoglobulin G (IgG) isotypes in sera and gamma interferon (IFN-γ) and interleukin-4 (IL-4) produced in splenocytes. The innate and adaptive immune responses were measured in mice immunized as described above. The results showed that ginsenoside Rg1 had adjuvant properties in stimulating IgG, splenocyte proliferation, and mRNA expression of cytokines IFN-γ and IL-4, as well as the expression of cell surface marker TLR4 in the HBsAg-immunized mice. These results indicate that Rg1 enhances both Th1 (IgG2b and IFN-γ) and Th2 (IgG1 and IL-4) responses. In addition, the TLR4 signaling pathway is involved in the adjuvant activities of ginsenoside Rg1.

Oleanolic acid rejuvenates testicular function through attenuating germ cell DNA damage and apoptosis via deactivation of NF ‐κB, p53 and p38 signalling pathways

Inflammation can cause degenerative changes of reproductive function. Oleanolic acid (OA), the effective component from Ligustrum lucidum Ait., exhibits significantly anti‐inflammation and antiageing activity. However, whether OA restores testicular dysfunction via inhibition of inflammation with ageing is unclear. Here, in a natural ageing rat model, we investigated the protection effects of OA and its mechanism of action.

Total flavonoids of Epimedium reduce ageing-related oxidative DNA damage in testis of rats via p53-dependent pathway

Increased DNA damage in testis is considered as a major factor for ageing‐related dysfunction. Total flavonoids of Epimedium (TFE), the main active compositions of Epimedium, have been used to treat sexual dysfunction and delay ageing. However, whether TFE could improve ageing‐related testicular dysfunction remains unknown. Therefore, we investigated the protection effects of TFE and its mechanisms of action in a naturally ageing rat model. Eighteen‐month‐old SD rats were randomised to receive either vehicle or TFE (10 and 20 mg/kg). Nine‐month‐old SD rats were used as adult controls. Morphology, protein expression and immunohistochemistry were determined. Compared with adult control group, intragastric administration of TFE for 6 months significantly improved testicular morphology, increased the activities of SOD and decreased the levels of MDA of testis. In addition, TFE decreased γH2AX expression levels and γH2AX focal formation in spermatogonia and primary spermatocyte with concomitant downregulation of 8‐OHdG levels. Furthermore, TFE inhibited p‐P53/p21 and chk1/chk2 expression levels. Collectively, TFE effectively reduce oxidative DNA damage in testis of ageing rats via a p53‐dependent pathway. Thus, inhibition of oxidative DNA damage is likely to represent a promising strategy for restoration of ageing‐related testicular dysfunction.

Panax notoginseng saponins attenuate cardiomyocyte apoptosis through mitochondrial pathway in natural aging rats

Panax notoginseng saponins (PNS) have been widely used in the cardiovascular system for the treatment of cardiovascular diseases and stroke in China. In this study, we investigated the anti‐apoptotic effect of PNS on cardiomyocytes in the natural aging rat and explored the potential mechanisms regarding oxidative stress and mitochondrial function signaling pathways. Male Sprague–Dawley rats were randomly divided into five groups: adult control (3‐month old), aging control (24‐month old), and different doses of PNS‐treated aging rat groups (10, 30, 60 mg/kg/day, orally). After treatment of PNS or saline for 6 months, the effects of PNS on the cardiomyocytes were evaluated. Results showed that PNS significantly improved the morphological changes in myocardium, prevented the increase of cardiomyocyte apoptosis in the aging rats, and improved mitochondrial dysfunction associated aging in a dose‐dependent manner. PNS also significantly reversed the down‐regulation of FoxO3a and Mn‐SOD and up‐regulated PGC‐1α, LC3β, and Beclin‐1 levels. Our data demonstrated that during aging, mitochondrial dysfunction caused an increase of oxidative damage, which played a key role in cardiomyocyte apoptosis. PNS exerted an anti‐apoptotic effect via attenuating oxidative damage through oxidative stress‐ and mitochondrial function‐related signaling pathways.

Preventive effects of total saponins of Panax japonicus on fatty liver fibrosis in mice

Introduction Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat accumulates in the liver of a patient without a history of alcohol abuse. Fatty liver fibrosis, a severe form of NAFLD, is a key step which can be reversed by effective medical intervention. This paper aims to describe the protective role and mechanisms of action of total saponins of Panax japonicus (SPJ) against fatty liver fibrosis in mice. In this study, fatty liver fibrosis was induced by a high-fat (HF) diet combined with intraperitoneal injection of porcine serum. Material and methods The fatty liver fibrosis model was induced by HF diet combined with intraperitoneal injection of porcine serum. The endoplasmic reticulum stress (ERS) response and C/EBP homologous protein (CHOP) and p-Jun N-terminal kinase (JNK)-mediated apoptosis and inflammation were assessed by serum biochemistry, hematoxylin-eosin (H + E), Masson and electronic microscopy staining, Hyp content detection, Western blotting and real time polymerase chain reaction (RT-PCR). Results Saponins of Panax japonicus could significantly improve liver function and decrease the lipid level in the serum. The liver steatosis, collagen fibers and inflammatory cell infiltration were significantly improved in the SPJ group according to microscope observation. The RT-PCR analysis revealed that the collagen I (Coll), α smooth muscle actin (α-SMA), tissue inhibitors of MMPs (TIMP), CHOP and GRP78 mRNA expression levels were distinctly weakened by SPJ treatment; and western blotting analysis indicated that the phosphorylated JNK (p-JNK), Coll and 78 kD glucose-regulated protein (GRP78) protein expression levels were significantly alleviated, which might be associated with the inhibition of the ERS response and the CHOP and JNK-mediated apoptosis and inflammation pathway. Conclusions Based on this research, SPJ as a preventive medicine has great potential in prevention of liver fibrosis.

Regulatory effects of saponins from Panax japonicus on colonic epithelial tight junctions in aging rats

Background Saponins from Panax japonicus (SPJ) are the most abundant and main active components of P. japonicus, which replaces ginseng roots in treatment for many kinds of diseases in the minority ethnic group in China. Our previous studies have demonstrated that SPJ has the effects of anti-inflammation through the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways. The present study was designed to investigate whether SPJ can modulate intestinal tight junction barrier in aging rats and further to explore the potential mechanism. Methods Aging rats had been treated with different doses (10 mg/kg, 30 mg/kg, and 60 mg/kg) of SPJ for 6 mo since they were 18 mo old. After the rats were euthanized, the colonic samples were harvested. Levels of tight junctions (claudin-1 and occludin) were determined by immunohistochemical staining. Levels of proinflammatory cytokines (interleukin-1β and tumor necrosis factor-α) were examined by Western blot. NF-κB and phosphorylation of MAPK signaling pathways were also determined by Western blot. Results We found that SPJ increased the expression of the tight junction proteins claudin-1 and occludin in the colon of aging rats. Treatment with SPJ decreased the levels of interleukin-1β and tumor necrosis factor-α, reduced the phosphorylation of three MAPK isoforms, and inhibited the expression of NF-κB in the colon of aging rats. Conclusion The studies demonstrated that SPJ modulates the damage of intestinal epithelial tight junction in aging rats, inhibits inflammation, and downregulates the phosphorylation of the MAPK and NF-κB signaling pathways.

Saponins from Panax japonicus attenuate age-related neuroinflammation via regulation of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways

Neuroinflammation is recognized as an important pathogenic factor for aging and related cognitive disorders. Mitogen-activated protein kinase and nuclear factor kappa B signaling pathways may mediate neuroinflammation. Saponins from Panax japonicus are the most abundant and bioactive members in rhizomes of Panax japonicus, and show anti-inflammatory activity. However, it is not known whether saponin from Panax japonicus has an anti-inflammatory effect in the aging brain, and likewise its underlying mechanisms. Sprague-Dawley rats were divided into control groups (3-, 9-, 15-, and 24-month-old groups) and saponins from Panax japonicus-treated groups. Saponins from Panax japonicus-treated groups were orally administrated saponins from Panax japonicus at three doses of 10, 30, and 60 mg/kg once daily for 6 months until the rats were 24 months old. Immunohistochemical staining and western blot assay results demonstrated that many microglia were activated in 24-month-old rats compared with 3- and 9-month-old rats. Expression of interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase increased. Each dose of saponins from Panax japonicus visibly suppressed microglial activation in the aging rat brain, and inhibited expression levels of the above factors. Each dose of saponins from Panax japonicus markedly diminished levels of nuclear factor kappa B, IκBα, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38. These results confirm that saponins from Panax japonicus can mitigate neuroinflammation in the aging rat brain by inhibition of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways.