The Cellular and Molecular Mechanism of Radiation-Induced Lung Injury.

The lung is one of several moderately radiosensitive organs. Radiation-induced lung injury (RILI), including acute radiation pneumonitis and chronic radiation-induced pulmonary fibrosis, occurs most often in radiotherapy of lung cancer, esophageal cancer, and other thoracic cancers. Clinical symptoms of RILI include dry cough, shortness of breath, chest pain, fever, and even severe respiratory failure and death. The occurrence of RILI is a complex process that includes a variety of cellular and molecular interactions which ultimately leads to large fibroblast accumulation, proliferation, and differentiation, resulting in excessive extracellular matrix deposits, causing pulmonary fibrosis. The progress that has been made in recent years in the understanding of cellular and molecular mechanisms of RILI is summarized in this review.

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.

Tougu Xiaotong capsule inhibits the tidemark replication and cartilage degradation of papain-induced osteoarthritis by the regulation of chondrocyte autophagy.

The tidemark is located between calcified and non-calcified cartilage matrices. Tidemark replication plays an important role in the pathogenesis of osteoarthrosis (OA). Autophagy, or cellular self-digestion, is an essential cellular homeostasis mechanism that was found to be deficient in osteoarthritic cartilage. This study evaluated the effects of Tougu Xiaotong capsule (TXC) on the tidemark replication and cartilage degradation, and also investigated LC3 I/II, which executes autophagy, the potential role of ULK1, an inducer of autophagy, and Beclin1, a regulator of autophagy, in the development of a papain-induced OA in rat knee joints. Using a papain-injected knee rat model, standard histological methods were used to validate our model as well as treatment with TXC or glucosamine (GlcN). After 12 weeks of treatment, the changes of cartilage structure were observed by digital radiography (DR), optical microscopy, scanning electron microscopy and transmission electron microscopy, and the LC3 I/II, ULK1 and Beclin1 levels were measured by western blotting. Cartilage degradation was evaluated by the Mankin score on paraffin-embedded sections stained with Safranin O-fast green. TXC was found to improve the arrangement of subchondral bone collagen fibers and calcium phosphate crystals, inhibit the tidemark replication and delay the cartilage degradation in the papain-induced OA. Our results also showed that LC3 I/II, ULK1 and Beclin1 levels in both the TXC+OA and GlcN+OA groups were significantly increased compared to those in the OA group. The results indicate that TXC could inhibit the tidemark replication and cartilage degradation by the regulation of chondrocyte autophagy.

Effects of Bauhinia championii (Benth.) Benth. polysaccharides on the proliferation and cell cycle of chondrocytes.

It has been recently shown that polysaccharides isolated from plants exhibit a number of beneficial therapeutic properties. Bauhinia championii (Benth.) Benth. has been widely used for the clinical treatment of knee osteoarthritis (OA) in China. However, the underlying molecular mechanisms of knee OA treatment have yet to be elucidated. In the present study, we investigated the effects of Bauhinia championii (Benth.) Benth. polysaccharides (BCBPs) on the proliferation and cell cycle of chondrocytes on 4-week-old male Sprague Dawley rats. Immunohistochemical staining was used to identify chondrocytes and an MTT assay was used to evaluate cell viability. Flow cytometry was used for cell cycle analysis. The mRNA and protein expression levels of cyclin D1, CDK4 and CDK6 in chondrocytes were detected using reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The data demonstrate that BCBP treatment increased the viability of chondrocytes. In addition, BCBP treatment reduced the cell population in the G0/G1 phase, whereas the cell population was increased in the S phase. Furthermore, BCBP treatment enhanced the expression of cyclin D1, CDK4 and CDK6. These results indicate that BCBP treatment promotes cell proliferation by accelerating the G1/S transition.

Chemical constituents of volatile oil from Pyrolae herba and antiproliferative activity against SW1353 human chondrosarcoma cells.

The objective of the present study was to identify chemical constituents of volatile oil from Pyrolae herba (PHVO) and evaluate the antiproliferative activity of PHVO against SW1353 human chondrosarcoma cells. The volatile oil from Pyrolae herba was prepared by hydrodistillation and characterized by gas chromatography-mass spectroscopy (GC-MS). A total of 12 components in PHVO were identified representing 81.62% of the total integrated chromatographic peaks. The major compounds were found to be n-hexadecanoic acid (29.29%), cedrol (17.08%), 6,10,14-trimethyl-2-pentadecanone (9.59%) and cis-9-octadecadienoic acid (8.23%). The antiproliferative activity of PHVO against SW1353 cells was investigated using MTT assay, flow cytometry and western blot analysis. Our results demonstrated that PHVO inhibited SW1353 cell viability in a dose- and time-dependent manner. Furthermore, PHVO treatment decreased the number of cells entering the S phase and caused a reduction in the expression of cyclin D1, cyclin-dependent kinase (CDK)4 and CDK6, whereas it caused an increase in the expression of p21. PHVO demonstrated potent antitumor activity against SW1353 cells, suggesting its potential use as a therapeutic agent in the treatment of chondrosarcoma.

Achyranthes bidentata polysaccharides induce chondrocyte proliferation via the promotion of the G1/S cell cycle transition.

Achyranthes bidentata polysaccharides (ABPS) are the major bioactive constituents of Radix Achyranthes bidentata (AB), which has been widely used in traditional Chinese medicine for the treatment of osteoarthritis. However, the molecular mechanisms behind the therapeutic effect of ABPS remain unclear. In the present study, chondrocytes were isolated from Sprague-Dawley rats. The effects of ABPS on the G1/S cell cycle transition in primary chondrocytes were investigated. The chondrocytes treated with and without ABPS were analyzed and it was observed that ABPS treatment was able to enhance chondrocyte proliferation in a dose- and time-dependent manner and promote the progression of chondrocyte cell cycle proliferation via the promotion of the G1 to S phase transition. Furthermore, using RT-PCR and western blot analysis, ABPS were observed as significantly upregulating the expression of cyclin D1 and the cyclin-dependent kinases (CDKs) CDK4 and CDK6. These results suggest that ABPS are able to promote chondrocyte proliferation via the promotion of the G1/S cell cycle transition.

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.

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.