Reproductive and immune-related consequences of Achillea fragrantissima (Forssk.) in male rats via modulation of steroidogenesis- and immune-related genes expression

Introduction Achillea fragrantissima (AFG) is known for its medicinal properties, while different Achillea species have shown both beneficial and detrimental impacts on male fertility. This investigation evaluated the effects of AFG oral administration on behavior, steroidogenesis, and immune-related gene expression in Sprague-Dawley male rats. Methods Forty-five mature rats were randomly grouped into: Control, Low-dose group (AFG-L: 500 mg/kg extract), and High-dose group (AFG-H: 1000 mg/kg extract). The AFG extract was orally administered for 30 days. Behavioral, hematological, reproductive, immune, and oxidative stress-related indices were evaluated. Results The AFG administration at both doses significantly ( p < 0.05) modulated the feeding and drinking, hole-board, swimming performance, tube dominance, and modified Y-maze tests outcomes. The AFG-L group displayed significant ( p < 0.05) increases in final weight gain, sperm count, motility, and viable sperms %, with significant ( p < 0.05) reductions in aberrant and dead sperms %. AFG significantly ( p < 0.05) increased phagocytic index (PhI) and phagocytic %. However, erythrogram and leukocyte counts were not significantly altered. The AFG-L group displayed significant ( p < 0.05) increases in serum testosterone (TEST), FSH, LH, and Estradiol (E2) hormones. Additionally, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-ɑ) concentrations were significantly decreased ( p < 0.05). AFG extract administration significantly improved ( p < 0.05) lipid profile, increased the testicular and splenic glutathione peroxidase (GPx), superoxide dismutase (SOD), total antioxidant capacity (TAC) levels, whereas the malondialdehyde (MDA), protein carbonyl (PCO), 8-hydroxy-2-deoxyguanosine (8OH2dG), and testicular lactate dehydrogenase (LDH) levels were significantly reduced ( p < 0.05). AFG administration significantly ( p < 0.05) upregulated mRNA expression of StAR, CYP11A1, CYP17A1 , and HSD17B3 in the testes, as well as CD3, CD4, CD20 , and IL-10 in the spleen, but expression levels of CYP19A1 and Caspase -3 in testes, along with CD8 and Caspase-3 in spleen, were significantly ( p < 0.05) downregulated. The AFG-L group maintained normal testicular architecture with preserved seminiferous tubules and only mild interstitial edema alongside mild splenic sinusoid dilatation with macrophage infiltration. In contrast, the AFG-H group exhibited significant histopathological alterations, including irregular seminiferous tubules, reduced mature sperm, and increased interstitial edema, while the spleen showed preserved lymphoid follicles with congested vasculature. Discussion The findings of the ongoing work demonstrate for the first time that A. fragrantissima extract exerts reproductive and immune-enhancing outcomes in male rats, with the low dose exhibiting greater efficacy than the high dose, indicating a clear dose-dependent response.