Effects of leptin on stress-induced changes of caspases in rat gastric mucosa

Acetyl-L-carnitine attenuates chronic ethanol-induced oxidative stress, ER stress and apoptosis in rat gastric tissue

Consuming alcohol affects almost all organs. Acetaldehyde, formed as the main product as a result of alcohol metabolism, causes the production of free superoxide radicals when oxidized, and accordingly oxidative and apoptotic processes are triggered. There are studies showing that carnitine has effects on oxidative and apoptotic processes that occur in various conditions. However, the mechanisms showing the effects of L-carnitine on these effects of alcohol have not been fully elucidated. In our study, the effects of acetyl-L-carnitine administration on the molecular mechanisms of oxidative stress, endoplasmic reticulum stress, and apoptotic parameters in gastric tissue of rats chronically exposed to alcohol were investigated. Hematoxylin-eosin staining was used for histopathological studies. Endoplasmic reticulum stress markers were detected with immunohistochemical staining and western blotting. Apoptotic index was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Total oxidant and antioxidant status were examined by ELISA. Our results showed that chronic alcohol administration caused a significant increase in TOS levels, an indicator of oxidative stress, the levels of ER-stress-associated proteins XBP1, GRP78, and CHOP, and % apoptotic index values in rat gastric tissues. Additionally, it was determined that acetyl-L-carnitine administration caused an improvement in those values. Based on our data, we can conclude that acetyl-L-carnitine has a tissue protective effect by scavenging free oxygen radicals and reducing ER stress-related proteins XBP1, GRP78, and CHOP and apoptosis in chronic ethanol-administered rats, and that this natural antioxidant may be beneficial in the treatment of oxidative stress-induced diseases.

Sodium metabisulfite induces lipid peroxidation and apoptosis in rat gastric tissue

Sodium metabisulfite (Na 2S2O5) is used as an antioxidant and antimicrobial agent in a variety of drugs and functions as a preservative in many food preparations. This study was performed to elucidate the dose-dependent effects of sodium metabisulfite ingestion on rat gastric tissue apoptotic changes and lipid peroxidation. Forty male wistar rats, aged 3 months were used. They were randomly divided into four groups: control (C), the group treated with Na2S2O5 (10 mg/kg; S1), the group treated with Na2S2O5 (100 mg/kg; S2), the group treated with Na2S2O5 (260 mg/kg; S3). Na 2S2O5 was given by intragastric intubation for 35 days. In the S2 and S3 groups, malondialdehyde (MDA) levels increased markedly when compared with the control group. High doses of sulfite administration elevated number of apoptotic cells both in mucosa and submucosa layers of stomach in parallel with increased MDA levels. These results suggest that sodium metabisulfite increased lipid peroxidation and thus number of apoptotic cells on gastric tissue in dose-dependent manner.