OBJECTIVE: To investigate the effects of sera from rats fed with tablets (HGT) on endoplasmic reticulum (ER) stress in a steatotic hepatocyte model of free fatty acids (FFAs)-induced nonalcoholic fatty liver disease (NAFLD) and explore the possible mechanism. METHODS: FFAs prepared by mixing oleic acid and palmitic acid at the ratio of 2:1. HepG2 cells were treated with the sera from rats fed with low-, moderate-or high-dose HGT (HGT sera) or sera of rats fed with fenofibrate (fenofibrate sera), followed by treatment with 1 mmol/L FFAs for 24 h to induce hepatic steatosis. Oil red O staining was used to observe the distribution of lipid droplets in the cells. The biochemical parameters including triglyceride (TG), lactated hydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured using a commercial kit. The morphological changes of the ER in the cells were observed using transmission electron microscopy. The protein/mRNA expressions of ER stress-related signal molecules including GRP78, PERK, p-PERK, ATF6, ATF4, CASPASE-12, CHOP, XBP-1, PKC, and p-PKC-δ were detected using Western blotting and/or quantitative real-time PCR (qRT-PCR). The changes in the protein expressions of GRP78, p-PERK, CASPASE-12 and CHOP were also detected in cells with transient transfection of PKC-δ siRNA for PKC-δ knockdown. RESULTS: Compared with the control cells, the cells treated with FFAs showed significantly increased levels of TG, AST, and ALT ( < 0.05). Compared with FFAs-treated cells, the cells pretreated with HGT sera or fenofibrate sera all showed significantly decreased TG, AST and ALT levels ( < 0.05), reduced accumulation of the lipid droplets ( < 0.05), and lowered protein or mRNA expression levels of GRP78, p-PERK, ATF6, ATF4, CHOP, CASPASE-12, XBP-1 and p-PKC-δ ( < 0.05). PKC-δ knockdown caused significantly reduced protein expressions of GRP78, p-PERK, CASPASE-12 and CHOP in the cells with FFA-induced hepatic steatosis ( < 0.001); treatment with high-dose HGT serum more significantly reduced the expressions of GRP78 ( < 0.001) and P-PERK ( < 0.01) in FFAs-induced cells with PKC-δ knockdown. CONCLUSIONS HGT serum can effectively prevent FFAs-induced steatosis in HepG2 cells by alleviating ER stress, in which PKC-δ may act as an important target.
Alanine Transaminase ; blood ; Animals ; Aspartate Aminotransferases ; blood ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; Endoplasmic Reticulum ; ultrastructure ; Endoplasmic Reticulum Stress ; drug effects ; Fatty Acids, Nonesterified ; Fenofibrate ; administration & dosage ; Hep G2 Cells ; Humans ; Hypolipidemic Agents ; administration & dosage ; Microscopy, Electron, Transmission ; Non-alcoholic Fatty Liver Disease ; blood ; etiology ; prevention & control ; RNA, Messenger ; blood ; Rats ; Serum ; Tablets ; Triglycerides ; blood

OBJECTIVE: To compared the effect of different drying methods on drying characteristics, water effective diffusion coefficient and biased activation energy of Codonopsis Radix and to definite 3 different drying methods of varying temperature(45-55-60, 60-55-45, 60-45-60℃) and 3 constant temperature(45, 55, 60℃) on drying characteristic curves of different commercial grades of Codonopsis Radix. METHODS: Used R2, χ2 and RMSE as evaluation indexes, 10 typical drying kinetic models were selected to fit the drying curve of Codonopsis Radix, and the effective moisture diffusion coefficient and biased activation energy under different drying method were calculated. RESULTS: It was found that the Midilli model could well describe the drying process of different commercial grades of Codonopsis Radix, the water ratio of Codonopsis Radix showed an exponential downward trend. If the initial drying temperature was set above 55℃, the maximum drying rate could be reached within 2 h. And commercial grades temperature had certain influence on the effective water diffusion coefficient of Codonopsis Radix. Under the same temperature condition, the average speed of moisture migration during drying of Codonopsis Radix was:first-class> second-class>third-class, and the Deffwere 10.433 9×10-8, 5.545 2×10-8, 2.249 6×10-8·m2·s, respectively. The calculated bias activation energy of Codonopsis Radix was 2.943×104-4.378×104 J·mol-1, the order of bias activation energy of different drying methods was as follows:60-55-45℃ variable temperature<60-45-60℃ variable temperature<45-55-60℃ variable temperature<55℃ constant temperature<60℃ constant temperature <45℃ constant temperature, which indicated that the moisture in the medicinal materials was more likely to evaporate and overflow and consumes less energy than the constant temperature drying. In particular, the bias activation energy of 60-55-45℃ drying method was 77.54% and 81.86% of the other 2 variable temperature drying methods, which were 67.22%, 75.13% and 74.26% of the 3 kinds of constant temperature drying. CONCLUSION The use of cooling mode in the drying process can save more time and energy, and can provide experimental basis for the improvement of drying technology and optimization of drying process of Codonopsis Radix.