Lemon Balm Attenuates Methotrexate‐Induced Testicular Damage Through Modulation of Oxidative Stress and p‐p38 <scp>MAPK</scp> Signaling

Abstract

This study investigated the protective effects of Lemon balm (Melissa officinalis) extract against methotrexate (MTX)-induced testicular toxicity in male Wistar rats. Thirty-two rats were divided into four groups: control, Lemon balm, MTX, and MTX + Lemon balm. MTX was administered intraperitoneally at 20 mg/kg on day 23, while Lemon balm was given orally at 100 mg/kg daily. The MTX-treated group showed significant reductions in body and testicular weight, sperm quality, and reproductive hormone levels [testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH)]. There was also a marked increase in oxidative stress markers [malondialdehyde (MDA), nitric oxide (NO)] and inflammation markers [tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, 8-hydroxy-2'-deoxyguanosine (8-OHdG)]. Immunohistochemical analysis revealed strong p-p38 mitogen-activated protein kinase (MAPK) expression in testicular tissues of the MTX group. Co-treatment with Lemon balm significantly improved sperm parameters and hormone levels while reducing oxidative and inflammatory responses, including marked downregulation of p-p38 MAPK expression. These findings suggest that Lemon balm extract may alleviate MTX-induced testicular toxicity through antioxidant, anti-inflammatory, and p-p38 MAPK pathway modulation.