L-Carnitine reduces the negative effects of formalin on sperm parameters, chromatin condensation and apoptosis in mice: An experimental study

Formalin is commonly applied as an antiseptic and tissue fixative. It has reactive molecules that lead to its cytotoxic effects. According to recent studies, formalin causes a change in the testicular and sperm structure and L-carnitine (LC) acts as an antioxidant to counteract its effects.

This study aimed to investigate the protective effects of LC on the parameters, chromatin condensation and apoptosis of mice sperm exposed to formalin.

In this experimental study, 24 balb/c mice (25-40 gr ,10-12 wk) were divided into three groups (n = 8/each): group I without any injections or gavage; group II, received 10 mg/ kg formalin intraperitoneally (I.P); and group III was exposed to formalin and LC, where a dose of 10 mg/kg formalin was injected I.P daily and LC the dose of 100 mg/kg was kept in a solvent solution. After 31 days, the sperm examination was performed as follows: to evaluate chromatin and DNA quality of the sperm, we applied aniline blue (AB), toluidine blue (TB), chromomycin A3 (CMA3), and terminal transferase-mediated deoxy uridine triphosphate biotin end labeling (TUNEL) tests.

Sperm parameters such as count, motility, morphology, and viability displayed a significant decrease in the formalin group. While the data exhibited a considerable augment in sperm parameters in the formalin + LC than the formalin and control groups (p < 0.001), significant differences were detected between groups with respect to TB staining, TUNEL test, CMA3 test and AB staining in the formalin and formalin + LC groups.

LC can reduce the negative effects of formalin on sperm parameters, chromatin stability, and percentage of apoptosis in an animal model.