Naringenin protects against isoniazid- and rifampicin-induced 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); low- and 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 58.15 ± 10.54 U/L; 98.36 ± 14.78 U/L, 92.41 ± 13.59 U/L 133.05 ± 19.36 U/L; 5.34% ± 0.26%, 4.93% ± 0.25% 5.71% ± 0.28%; 2.76 ± 0.67 nmol/mgprot, 2.64 ± 0.64 nmol/mgprot 4.49 ± 1.12 nmol/mgprot; 5.91 ± 1.31 mg/gprot, 6.42 ± 1.42 mg/gprot 3.11 ± 0.73 mg/gprot; 137.31 ± 24.62 U/mgprot, 148.83 ± 26.75 U/mgprot 102.34 ± 19.22 U/mgprot; all < 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 INH- and 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 suppression of oxidative stress and hepatocyte apoptosis.