Wenlie Chen

Experimental study on the suppression of sodium nitroprussiate-induced chondrocyte apoptosis by Tougu Xiaotong Capsule (透骨消痛胶囊)-containing serum

ObjectiveTo study the mechanism of action of Tougu Xiaotong Capsule (透骨消痛胶囊, TGXTC) ex vivo in suppressing chondrocyte (CD) apoptosis induced by sodium nitroprussiate (SNP).MethodsThirty New Zealand rabbits, 2 months old, were randomized by lottery into five groups, six in each: the blank group treated with saline, the positive control group treated with Zhuanggu Guanjie Pill (壮骨关节丸, 70 mg/kg), and the three experimental groups, EGA, EGB, and EGC, treated with low dose (35 mg/kg), moderate dose (70 mg/kg), and high dose (140 mg/kg) of TGXTC, respectively. All treatments were administered via gastrogavage twice a day for 3 days. Arterial blood was collected from the abdominal aorta and drug or drug metabolites-containing serum was prepared. CDs obtained from knee joints of 16 four-week-old New Zealand rabbits were cultured to the third passage and confirmed by toluidine blue staining. SNP of various final concentrations (0, 0.5, 1.0, and 2.0 mmol/L) was used to induce CD apoptosis, and the dosage-effect relationship of SNP in inducing CD apoptosis was determined. Serum samples from the blank, control, and three dosages of TGXTC-treated rabbits were tested in the CD culture in the presence of SNP. Cell apoptosis was determined by Hoechst 33342 staining, viability of CDs was quantified by MTT, CD apoptosis rate was determined by annexin V-FITC/PI staining, levels of p53 and Bcl-2 mRNA expression in CDs were determined with RT-PCR, and contents of caspase-3 and caspase-9 proteins were determined by colorimetry.ResultsCD apoptosis was induced by SNP at all concentrations tested and in a dose-dependent manner. The SNP concentration of 1 mmol/L and treatment duration of 24 h appeared to be optimal and were selected for the study. Serum samples from the positive control rabbits and from the two higher doses of TGXTC-treated rabbits showed reduction of SNP-induced CD apoptosis, decrease in p53 mRNA expression, inhibition of catalytic activities of caspase-3 and caspase-9, and increase in Bcl-2 mRNA expression when compared with the serum from the blank group (P<0.05).ConclusionTGXTC-containing sera antagonized SNP-induced CD apoptosis and the molecular basis for the action was associated with up-regulation of Bcl-2, down-regulation of p53 expression, and inhibition of caspase-3 and caspase-9 catalytic activities.

In vitro study of inhibitory millimeter wave treatment effects on the TNF-α-induced NF-κB signal transduction pathway

Abnormal activation of the nuclear factor-κB (NF-κB) in chondrocytes initiates the transcription of inflammatory mediators, promotes their generation and release, and amplifies initial inflammatory signals. This results in the release of chondral matrix-degrading enzymes and accelerates the degeneration of articular cartilage. As a non-pharmaceutical and non-invasive physical therapy regimen, millimeter wave treatment has been successfully used for the treatment of osteoarthritis. In this study, chondrocytes were derived from the cartilages of knee joints of 4-week-old male Sprague-Dawley rats and were mechanically digested by collagenase type II treatment for further culture in vitro. The third-passage chondrocytes were stained with toluidine blue and treated with a gradient of tumor necrosis factor-α (TNF-α) for various times. Chondrocytic activity was measured by MTT assay, and the apoptotic rate of the chondrocytes was determined with Hocehst 33342 staining to identify effective treatment concentrations and durations and to establish an apoptosis model for the chondrocytes in response to TNF-α. Using this model, the chondrocytes were randomly divided to receive millimeter wave treatment for various times. The apoptotic rate of the chondrocytes was measured by Annexin V-FITC staining and the protein expression levels of RIP, TAK1, IκB kinase (IKK)-ß, IκB-α and NF-κB, were determined by Western blotting. Chondrocytic structure was examined by transmission electronic microscopy. The apoptotic rates were significantly lower at 4 and 8 h of treatment than at 0 and 2 h. The expression levels of RIP, TAK1, IKK-ß and NF-κB were also significantly lower at 4 and 8 h than at 0 and 2 h, whereas that of IκB-α was significantly higher at 4 and 8 h than at 0 and 2 h. Therefore, we can conclude that millimeter wave treatment can inhibit the activation of the TNF-α-mediated NF-κB signal transduction pathway through the down-regulation of RIP, TAK1, IKK-ß and NF-κB, and the up-regulation of IkB-α, in chondrocytes.

Duhuo Jisheng Decoction promotes chondrocyte proliferation through accelerated G1/S transition in osteoarthritis

Duhuo Jisheng Decoction (DHJSD), a well known traditional Chinese folk medicine, is used for eliminating stagnation, removing blood stasis, promoting blood circulation and alleviating pain; it is commonly used for the treatment of various diseases, including osteoarthritis (OA). However, the molecular mechanisms behind the therapeutic effects of OA remain unclear. In the present study, the effects of DHJSD on the morphology of articular cartilage and the G1/S cell cycle progression in chondrocytes, as well as the underlying mechanisms, were investigated. A total of 27 two‑month‑old male Sprague Dawley rats were randomly divided into 3 groups: the control group (no papain-induced OA; received an equivalent amount of saline only), the model group (papain-induced OA; received an equivalent amount of saline only) and the DHJSD group [papain-induced OA; received a clinical oral dose of DHJSD (9.3 g/kg/day)]. After 8 consecutive weeks of treatment, the morphological changes in articular cartilage were observed under an optical microscope and by transmission electron microscopy (TEM) and the mRNA and protein expression levels of cyclin D1, CDK4, CDK6, retinoblastoma protein (Rb) and p16 were measured by RT‑PCR and immunohistochemistry, respectively. Treatment with DHJSD significantly improved the arrangement of collagen fibers in the articular cartilage, as well as its structure and reduced cell degeneration compared with the model group. The mRNA and protein expression levels of cyclin D1, CDK4, CDK6 and Rb in the DHJSD‑treated group were significantly increased compared with those in the model group, whereas p16 expression was significantly downregulated. Taken together, these results indicate that DHJSD treatment promotes chondrocyte proliferation by promoting the G1/S checkpoint transition in the cell cycle and by upregulating the expression of cyclin D1, CDK4, CDK6 and Rb and downregulating the expression of p16 and this may, in part, explain its clinical efficacy in the treatment of osteoarthritis.

Millimeter wave radiation induces apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 human chondrosarcoma cells.

The efficacy and safety of millimeter wave radiation has been proven for various types of malignant tumors. However, the mechanisms underlying effects of millimeter wave radiation on apoptosis are still unclear. The present study was undertaken to examine the effects of millimeter wave radiation on cell apoptosis and mitochondrial membrane potential, and to determine the molecular mechanism of millimeter wave radiation-induced apoptosis by investigating the expression of Bcl-2 family proteins (Bcl-2, Bax), caspase-9 and caspase-3 in SW1353 cells. We found that millimeter wave radiation suppressed the viability of SW1353 cells, demonstrating that millimeter wave radiation induced cell apoptosis and reduced cell viability in a time-dependent manner. Furthermore, we observed that treatment of cells with millimeter wave radiation significantly induced loss of mitochondrial membrane potential, upregulated proapoptotic Bax, caspase-9 and caspase-3, but did not significantly change levels of antiapoptotic Bcl-2. These data suggested that millimeter wave radiation may induce apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 cells.

Millimeter wave treatment promotes chondrocyte proliferation via G1/S cell cycle transition

Millimeter waves, high-frequency electromagnetic waves, can effectively alleviate the clinical symptoms in osteoarthritis patients, as a non-pharmaceutical and non-invasive physical therapy regimen. However, the molecular mechanisms of the therapeutic effects of millimeter wave treatment are not well understood. In the present study, the effect of millimeter waves on the G1/S cell cycle progression in chondrocytes and the underlying mechanism was investigated. Chondrocytes isolated from the knee of SD rats were cultured and identified using toluidine blue staining. The second generation chondrocytes were collected and stimulated with or without millimeter waves for 48 h. Chondrocyte viability was analyzed using the MTT assay. The cell cycle distribution of chondrocytes was analyzed by flow cytometry. mRNA and protein expression levels of cyclin D1, cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) and p21 were detected using real-time PCR and western blotting, respectively. Millimeter wave stimulation was found to significantly enhance chondrocyte viability. Moreover, the percentage of chondrocytes in the G0/G1 phase was significantly decreased, whereas that in the S phase was significantly increased. In addition, following millimeter wave treatment, cyclin D1, CDK4 and CDK6 expression was significantly upregulated, whereas p21 expression was significantly downregulated. The results indicate that millimeter wave treatment promotes chondrocyte proliferation via cell cycle progression.

Bushen Zhuangjin Decoction promotes chondrocyte proliferation by stimulating cell cycle progression

Bushen Zhuangjin Decoction (BZD), a well-known formulation in Traditional Chinese Medicine, has been widely used for the treatment of osteoarthritis (OA). Due to the poor intrinsic repair capacity of chondrocytes, promoting the proliferation of chondrocytes is an efficient treatment to delay the progression of cartilage degradation. The present study, therefore, focused on the effect of BZD on chondrocyte proliferation, exploring the mechanism of BZD on the inhibition of cartilage degradation. Chondrocytes isolated from the knee articular cartilage of Sprague Dawley rats were cultured and identified by type II collagen immunohistochemistry. It was found that BZD promoted chondrocyte viability in a dose- and time-dependent manner. To investigate if BZD promoted the chondrocyte viability by stimulating the cell cycle progression a flow cytometer was used, and the results showed that the percentage proportion of G0/G1 cells was significantly lower, and the percentage proportion of S cells was significantly higher, in treated cells compared with that in untreated cells. To gain insight into the mechanism underlying the effect of BZD on the cell cycle progression, the mRNA and protein expression of cyclin D1, cyclin-dependent kinase 4 (CDK4), CDK6 and p21 was measured by reverse transcription-polymerase chain reaction and western blotting, respectively. The mRNA and protein expression of cyclin D1, CDK4 and CDK6 in the BZD-treated chondrocytes was significantly upregulated, while the mRNA and protein expression of p21 was significantly downregulated, compared with that in the untreated chondrocytes. These results suggested that BZD promoted chondrocyte proliferation by accelerating G1/S transition, indicating that BZD is a potential therapeutic agent for the treatment of OA.

Tougu Xiaotong formula induces chondrogenic differentiation in association with transforming growth factor-β1 and promotes proliferation in bone marrow stromal cells

Indian hedgehog (Ihh), one of the hedgehog gene families, is indicated in the regulation of chondrocyte differentiation. Tougu Xiaotong formula (TXF), a traditional Chinese medicinal compound, has been used for the treatment of bone and joint disease. However, the underlying molecular mechanisms of TXF on the function of bone marrow stromal cells (BMSCs) remain unclear. In the present study, the affect of TXF on proliferation and chondrogenic differentiation was investigated in primary BMSCs from four‑week‑old Sprague Dawley rats. The cell viability in BMSCs treated with TXF was higher compared to the untreated cells. Additionally, the percentage of G(0)/G(1) phase cells was significantly decreased, whereas that of the S phase cells was significantly increased. Furthermore, following TXF treatment, cyclin D1, cyclin‑dependent kinase 4 (CDK4) and CDK6 expression in BMSCs was significantly enhanced. The results showed that TXF had no cytotoxicity to BMSCs. To explore the effect of TXF on the differentiation in BMSCs, whether TXF induced chondrogenic differentiation of BMSCs by the regulation of Ihh signaling pathway was investigated. The protein expression of Ihh, Patched and Smoothened in the induction group were significantly increased when compared to those in the control group, and the highest protein level of Ihh was in the induction group that was treated with the combination of TXF and transforming growth factor‑β1 (TGF‑β1). In addition, TXF combined with TGF‑β1 significantly induced the protein expression of cartilage oligomeric matrix protein and collagen II compared to the TGF‑β1 group. Taken together, these results indicate that TXF promotes the proliferation via accelerating the G(1)/S transition, and induces chondrogenic differentiation in BMSCs by activation of the Ihh signaling pathway in association with TGF‑β1.

Tougu Xiaotong capsule promotes chondrocyte autophagy by regulating the Atg12/LC3 conjugation systems.

We have previously reported that Tougu Xiaotong capsule (TXC) inhibits tidemark replication and cartilage degradation by regulating chondrocyte autophagy in vivo. Autophagy, a cell protective mechanism for maintaining cellular homeostasis, has been shown to be a constitutively active and protective process for chondrocyte survival. However, it remains unclear whether TXC promotes chondrocyte autophagy by regulating the autophagy-related (Atg)12/microtubule-associated protein 1 light chain 3 (LC3) conjugation systems. Thus, in the present study, we investigated the effects of TXC on primary chondrocytes treated with cobalt chloride (CoCl2). We found that CoCl2 induced a decrease in chondrocyte viability and the autophagosome formation of chondrocytes, indicating that CoCl2 induced autophagic death in a dose- and time-dependent manner. To determine the effects of TXC on CoCl2-exposed chondrocytes, we assessed cell viability by MTT assay. Our results revealed that TXC enhanced the viability of CoCl2-exposed chondrocytes. To gain insight into the mechanisms responsible for the enhancing effects of TXC on CoCl2-exposed chondrocytes, the expression of Atg genes was assessed in chondrocytes exposed to CoCl2 and treated with or without TXC. The results revealed that the expression of beclin 1, Atg3, Atg5, Atg7, Atg10, Atg12 and LC3 II/LC3 I in the chondrocytes treated with TXC increased, compared to that in the untreated chondrocytes. In addition, ultrastructural analysis indicated that treated chondrocytes contained more autophagosomes than the untreated cells, suggesting that TXC increased the formation of autophagosomes in the chondrocytes to clear the CoCl2-induced autophagic death. Therefore, these data suggest that TXC is a potential therapeutic agent for the reduction of cartilage degradation that occurs in osteoarthritis.

Electro‑acupuncture ameliorates cognitive impairment via improvement of brain‑derived neurotropic factor‑mediated hippocampal synaptic plasticity in cerebral ischemia‑reperfusion injured rats

A previous study by our group found that electro-acupuncture (EA) at the Shenting (DU24) and Baihui (DU20) acupoints ameliorates cognitive impairment in rats with cerebral ischemia-reperfusion (I/R) injury. However, the precise mechanism of action has remained largely unknown. The present study investigated whether brain-derived neurotropic factor (BDNF) mediates hippocampal synaptic plasticity as the underlying mechanism. Rats were randomly divided into three groups: The sham operation control (Sham) group, the focal cerebral ischemia-reperfusion (I/R) group, and the I/R with EA treatment (I/R+EA) group. The I/R+EA group received EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints after the operation. EA treatment was found to ameliorate neurological deficits (P<0.05) and reduce the cerebral infarct volume (P<0.01). In addition, EA improved cognitive function in cerebral I/R-injured rats (P<0.05). Furthermore, EA treatment promoted synaptic plasticity. Simultaneously, EA increased the hippocampal expression of BDNF, its high-affinity tropomyosin receptor kinase B (TrkB) and post-synaptic density protein-95 (PSD-95) in the rats with cerebral I/R injury. Collectively, the findings suggested that BDNF-mediated hippocampal synaptic plasticity may be one mechanism via which EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints improves cognitive function in cerebral I/R injured rats.

Protective effects of the Tougu Xiaotong capsule on morphology and osteoprotegerin/nuclear factor-κB ligand expression in rabbits with knee osteoarthritis

The imbalance of subchondral bone remodeling is a common pathological feature in the progression of osteoarthritis. In the current study, using a rabbit model of knee osteoarthritis, the effects of the Tougu Xiaotong capsule (TGXTC) on the cartilage and subchondral bone were investigated. In addition, osteoprotegerin (OPG), an inducer of bone formation, and receptor activator of nuclear factor‑κB ligand (RANKL), a regulator of bone resorption in the subchondral bone, were assessed, in order to further explore the protective role of TGXTC in subchondral bone remodeling. The rabbit model of knee osteoarthritis, which was induced by a modified version of Hulths method, was treated with TGXTC or glucosamine hydrochloride for 4 or 8 weeks. Subsequently, the tibia and femur were harvested for observation of cartilage histology, and the subchondral bone was observed by scanning electron microscopy. The expression levels of OPG and RANKL at the gene and protein levels were determined by reverse transcription‑quantitative polymerase chain reaction and western blotting. TGXTC and glucosamine hydrochloride were identified to mitigate cartilage injury, reduce trabecular number and thickness and accelerate trabecular separation. It was additionally observed that the level of OPG mRNA and protein expression was reduced, and the RANKL mRNA and protein expression level was increased, in addition to the observation of a lower OPG/RANKL ratio in the TGXTC and hydrochloride groups. Taken together, these results suggest that TGXTC may mitigate cartilage injury and subchondral sclerosis, thus delaying the pathological development of osteoarthritis. This is suggested to be mediated partly through the reduction of OPG expression and increase of RANKL expression, which reduces the OPG/RANKL ratio, suppressing excessive bone formation.