Naringenin protects against isoniazid- and rifampicininduced apoptosis in hepatic injury

AIM To explore the protective effects and mechanisms of naringenin(NRG) on hepatic injury induced by isoniazid(INH) and rifampicin(RIF).METHODS Male mice were randomly divided into four groups and treated for 14 d as follows: normal control group was administered intragastrically with normal saline solution alone; model group was administered intragastrically with INH(100 mg/kg) and RIF(100 mg/kg); lowand high-dosage NRG pretreatment groups were administered intragastrically with different doses of NRG(50 or 100 mg/kg) 2 h before INH and RIF challenge. Mice were killed 16 h after the last dose of drug treatment to determine activity of serum transaminases. Oxidative stress was evaluated by measuring hepatic glutathione(GSH) and superoxide dismutase(SOD) and malondialdehyde(MDA) levels. Histopathological changes in hepatic tissue were observed under the optical microscope. Hepatocyte apoptosis was measured by TUNEL assay and caspase-3 activation. Expression of Bcl-2 and Bax in liver was determined by western blot.RESULTS Both low- and high-dosage NRG pretreatment obviously alleviated serum levels of alanine aminotransferase and aspartate aminotransferase, liver index, hepatic MDA content, and increased hepatic GSH content and SOD activity compared with the INH and RIF-treated group(44.71 ± 8.15 U/L, 38.22 ± 6.64 U/L vs 58.15 ± 10.54 U/L; 98.36 ± 14.78 U/L, 92.41 ± 13.59 U/L vs 133.05 ± 19.36 U/L; 5.34% ± 0.26%, 4.93% ± 0.25% vs 5.71% ± 0.28%; 2.76 ± 0.67 nmol/mgprot, 2.64 ± 0.64 nmol/mgprot vs 4.49 ± 1.12 nmol/mgprot; 5.91 ± 1.31 mg/gprot, 6.42 ± 1.42 mg/gprot vs 3.11 ± 0.73 mg/gprot; 137.31 ± 24.62 U/mgprot, 148.83 ± 26.75 U/mgprot vs 102.34 ± 19.22 U/mgprot; all P < 0.01 or 0.05). Histopathological evaluation showed obvious necrosis and inflammatory cell infiltration in liver of mice administered INH and RIF; however, mice pretreated with NRG showed minor hepatic injury. In addition, INH and RIF resulted in hepatocyte apoptosis, and NRG pretreatment dramatically suppressed INHand RIF-induced hepatocytes apoptosis. Furthermore, NRG-mediated anti-apoptotic effects seemed to be in connection with its regulation of Bax and Bcl-2 protein expression in hepatic tissue.CONCLUSION NRG might attenuate INH- and RIF-induced hepatic injury via suppression of oxidative stress and hepatocyte apoptosis.

Ionic conductivity of infiltrated Ln (Ln = Gd, Sm, Y)-doped ceria

This work studies the ionic conductivity of nanosized Gd-, Sm-, and Y-doped ceria prepared by the infiltration/impregnation method. The nanoparticles were deposited onto porous pure ceria substrates via infiltration- heating processes, and the conductivity was determined with the electrochemical impedance spectroscopy （EIS） using the conductive model for infiltrated phases. The conductivity of the infiltrated doped ceria changes with the doping amount, and Gd0.25Ce0.75O2-δ, Sm0.2Ce0.8O2-δ, and Y0.15Ce0.85O2-δ show the highest values of 2.56, 3.01, and 2.07 × 10-3 S.cm-1 at 600 ℃, respectively. Overall, Sin-doped samples show the highest conductivity, whileY-doped samples show the lowest conductivity. In con- sideration of the Bruggeman factor, the intrinsic conduc- tivity of the infiltrated doped ceria was calculated. Compared with the bulk doped ceria, the intrinsic con- ductivity is higher while the activation energy is lower, which may suggest different conduction mechanisms. Besides, co-doping effects on the conductivity of the infiltrated sample are less obvious than those of the bulk sample.