Tetrandrine Enhances Radiosensitization in Human Hepatocellular Carcinoma Cell Lines.

The goal of this study was to determine whether tetrandrine enhanced radiosensitization in different hepatocellular carcinoma cell lines and to elucidate the potential mechanism. We also tested whether PA28γ was regulated by tetrandrine. The human hepatocellular carcinoma cell lines HepG2 and LM3 were divided into six groups: control; low-dosage (0.5 or 5 µg/ml) tetrandrine alone; high-dosage (1.0 or 10 µg/ml) tetrandrine alone; irradiation alone; irradiation with low-dosage (0.5 µg/ml or 5 µg/ml) tetrandrine; and irradiation with high-dosage (1.0 µg/ml or 10 µg/ml) tetrandrine. Colony-forming assays were performed. Expression of cyclin and apoptosis-related proteins, including cyclin B1, phosphorylated cyclin-dependent kinase 1 [phospho-CDC2 (Tyr15)], Bax and caspase-3, as well as PA28γ expression, were evaluated using Western blot analysis. Apoptosis rate and cell cycle distribution were examined using flow cytometry analysis. Tetrandrine enhanced radiosensitivity in HepG2 and LM3 cells, as characterized by a narrower shoulder area and steeper linear area, and the enhanced radiosensitization increased with tetrandrine dosage. After tetrandrine treatment, the apoptosis rate significantly increased, whereas the proportion of cells in the G2 phase dramatically decreased in dose- and time-dependent manners after irradiation. However, the effect of reverse G2 arrest was weaker in p53-mutant cells (LM3 cells). Finally, we observed that tetrandrine downregulated PA28γ expression. Moreover, when PA28γ was downregulated, apoptosis and cell cycle distribution were also altered; however, the effects were weaker in p53-mutant cells. Therefore, we propose that tetrandrine-mediated apoptosis induction and G2 arrest attenuation are at least partly mediated by PA28γ.

Effect of cold stress on immunity in rats.

An increase in the morbidity of upper respiratory tract infections and the attack and exacerbation of autoimmune diseases has been observed to occur in the few days following sudden environmental temperature decreases, but the mechanisms for these phenomena are not well understood. To determine the effect of a sudden ambient temperature drop on the levels of stress hormones and T-lymphocyte cytokines in the plasma, the Toll-like receptor 4 (TLR4) expression of immunocompetent cells in rat spleens and the levels of regulatory T (Treg) cells in the peripheral blood, Sprague Dawley rats were divided into three groups of different ambient temperatures (20, 4 and -12°C). In each group, there were four observation time-points (1, 12, 24 and 48 h). Each ambient temperature group was subdivided into non-stimulation, lipopolysaccharide-stimulation and concanavalin A-stimulation groups. The levels of adrenocorticotropin (ACTH), epinephrine (EPI), angiotensin-II (ANG-II), interleukin-2 (IL-2), interferon-γ (IFN-γ), IL-4 and IL-10 in the plasma were determined using ELISA. The cellular expression levels of TLR4 and the presence of cluster of differentiation (CD)4+CD25+ and CD4+CD25+Forkhead box P3 (Foxp3)+ cells were determined using flow cytometry. The experiments demonstrated that the ACTH, EPI, ANG-II and IL-10 levels in the plasma were significantly increased at 4 and -12°C compared with those at 20°C, while the plasma levels of IFN-γ, IL-2 and IL-4, the TLR4 expression rates of immunocompetent cells in the rat spleen and the percentage of CD4+CD25+Foxp3+ Treg cells among the CD4+CD25+ Treg cells in the peripheral blood were decreased at 4 and -12°C compared with those at 20°C. These data indicate that cold stress affects the stress hormones and the innate and adaptive immunity functions in rats.

Neuroprotective effects of Rhizoma Dioscoreae polysaccharides against neuronal apoptosis induced by in vitro hypoxia.

Rhizoma Dioscoreae polysaccharides (RDPS) are the primary active ingredient of Rhizoma Dioscoreae, which is a traditional Chinese medicine. RDPS have previously been shown to scavenge reactive oxygen species, and protect against D-galactose-induced mimetic aging. The present study aimed to investigate the neuroprotective effects of RDPS against hypoxia-induced neuronal cell apoptosis. Neuronal cells harvested from pregnant Sprague-Dawley rats were divided into groups, as follows: i) Normal control group; ii) hypoxia-induced apoptosis neuronal cell model; iii) 0.025 g/l RDPS-treated group; iv) 0.05 g/l RDPS-treated group; v) 0.1 g/l RDPS-treated group; and vi) 0.25 g/l RDPS treated group. Neuronal cell viability was investigated using an MTT assay, and neuronal cell apoptosis was analyzed using Annexin V-fluorescein isothiocyanate/propidium iodide double-staining, Hoechst 33342 fluorescent staining, Rhodamine 123 staining, polymerase chain reaction and immunocytochemical staining. The RDPS-treated neuronal cells exhibited improved viability, and decreased hypoxia-induced mitochondrial injury and apoptosis. In addition, the mRNA and protein expression levels of caspase-3 and B-cell lymphoma (Bcl)-2-associated X protein (Bax) were significantly downregulated, whereas the mRNA and protein expression levels of Bcl-2 were significantly upregulated, in the RDPS-treated hypoxic neurons, as compared with the apoptosis model (P<0.05). Furthermore, the ratio of Bcl-2 expression:Bax expression significantly increased following RDPS treatment, as compared with the apoptosis model (P<0.05). The results of the present study suggested that RDPS may attenuate hypoxia-induced neuronal cell apoptosis by altering the expression levels of key apoptosis-regulating proteins in hypoxic neurons.

Radioprotective effect of kupffer cell depletion on hepatic sinusoidal endothelial cells.

Radiation-induced liver injury remains a clinical problem and data suggest that sinusoidal endothelial cells (SECs) are an important target. The purpose of this study was to determine whether the inhibition of Kupffer cells before exposure would protect SECs from radiation-induced injury. Sprague-Dawley rats were intravenously injected 24 h before irradiation with Kupffer cell inhibitor gadolinium chloride (GdCl3) (10 mg/kg body weight). Three groups of animals were treated: 1. control group (saline and sham irradiation); 2. GdCl3 + 30 Gy radiation group and 3. 30 Gy radiation only group. Specimens were collected at 2, 6, 12, 24 and 48 h after completion of each treatment. Liver tissue was assessed for inflammatory cytokine expression and radiation-induced SEC injury based on serum hyaluronic acid (HA) level, apoptosis and ultrastructural and histological analyses. The results showed that radiation exposure caused apoptosis of SECs, but not hepatocytes. Inflammatory cytokine expression, including tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) expression, was significantly attenuated in the GdCl3 + 30 Gy radiation group, compared with the 30 Gy radiation-only group (P < 0.05). The GdCl3 + radiation-treated rats exhibited significantly lower levels of HA and SEC apoptosis than the radiation-treated only rats at early time points, and radiation-induced liver injury was also attenuated. In conclusion, we hypothesize that selective Kupffer cell inhibition by gadolinium chloride was shown to reduce apoptosis in SECs caused by irradiation of the live and protected the liver against radiation-induced injury.

Neuroprotective effect of Atractylodes macrocephalaon polysaccharides in vitro on neuronal apoptosis induced by hypoxia.

Rhizoma Atractylodis macrocephalae have an important role in treating cerebrovascular diseases in Traditional Chinese Medicine (TCM). The purpose of the present study was to determine the neuroprotective effect of Atractylodis macrocephalaon polysaccharides (AMPS) on hypoxia-induced apoptosis of cerebral cortical neurons. Neuronal cells obtained from neonatal rats were divided into the following groups: Normal control (group C); apoptosis positive induced by hypoxia-reoxygenation culture of rat primary cerebral cortical neurons (group A); treated with 0.025 g/l AMPS prior to hypoxia culture of neurons (AMPS1); treated with 0.05 g/l AMPS (AMPS2); treated with 0.1 g/l AMPS (AMPS3); and treated with 0.25 g/l AMPS (AMPS4). Neuronal apoptosis was examined with Annexin V-fluorescein isothiocyanate/propidium iodide, Hoechst 33342 fluorescent staining, Rhodamine 123 staining, polymerase chain reaction assay and immunocytochemical staining. The results showed that the AMPS significantly prevented the growth inhibition, mitochondrial injury and apoptosis of neurons induced by hypoxia. The levels of Caspase-3 and Bax mRNAs and proteins were significantly downregulated by AMPS in neurons exposed to hypoxia, and the levels of B-cell lymphoma 2 (Bcl-2) protein was significantly upregulated by AMPS in neurons exposed to hypoxia, as compared with group A (P<0.05). The ratio of Bcl-2/Bcl-2-associated X protein (Bax) mRNA and protein was significantly increased by AMPS in neurons exposed to hypoxia as compared with group A (P<0.05). The observed improved neuronal growth and inhibition neuronal apoptosis by AMPS may be due to a decrease in the levels of Bax and Caspase-3 and an increase in the levels of Bcl-2 and the ratio of Bcl-2/Bax in hypoxic neurons.