Administration of Lacticaseibacillus casei CSL3 in Swiss Mice with Immunosuppression Induced by Cyclophosphamide: Effects on Immunological, Biochemical, Oxidative Stress, and Histological Parameters

The study aimed to evaluate the effects of supplementation with Lacticaseibacillus casei CSL3 in Swiss mice immunosuppressed with cyclophosphamide on immunological, biochemical, oxidative stress, and histological parameters. The animals were distributed into four groups (control, CSL3, cyclophosphamide, and CSL3 + cyclophosphamide), where two groups were treated with L. casei CSL3 (10 log CFU mL⁻¹) for 30 days, and two groups received chemotherapy (days 27 and 30—total dose of 250 mg kg⁻¹). Counts of lactic acid bacteria (LAB) and bile-resistant LAB in stool samples; blood count (erythrogram, leukogram, and platelets); serum total cholesterol levels; catalase enzyme activity; and thiobarbituric acid reactive substances (TBARS) levels in liver, kidney, and brain; IL-4 expression; IL-23, TNF-α, NF-κβ in the spleen; and histological changes in the liver, kidneys, and intestine were evaluated. The CSL3 + cyclophosphamide group showed a significant increase in bile-resistant LAB counts in feces (p = 0.0001), leukocyte counts, and expression of IL-23, TNF-α, and NF-κβ (p < 0.05) significantly reduced total cholesterol levels (p = 0.001) and protected liver damage of supplemented animals. For oxidative stress damage, the bacterium did not influence the results. It is concluded that the bacterium is safe at a concentration of 10 log CFU mL⁻¹ and has probiotic potential due to its positive influence on the immune response and lipid metabolism.