Investigation of the protective effects of hesperidin against the possible toxicity of nivolumab on the male reproductive system

Nivolumab is an immune checkpoint inhibitor and an effective immunotherapy drug. Hesperidin is a flavonoid with strong antioxidant activity. In this thesis study, the potential effects of hesperidin against the possible toxicity that nivolumab may cause in testicular tissue were investigated. 32 male Wistar Albino rats were used in the study. The animals were divided into 4 groups, with 8 animals in each group; Control, Nivolumab (3 mg/kg), Hesperidin (50 mg/kg), Nivolumab (3 mg/kg) + Hesperidin (50 mg/kg). After 30 days of drug administration, the animals were sacrificed and blood and testicular tissue samples were taken. Elisa, Real Time PCR and histopathological analyzes were performed to determine oxidative damage in testicular tissue. The results obtained showed that nivolumab caused oxidative stress by disrupting the total oxidant and antioxidant balance, and on the other hand, hesperidin reduced oxidative damage by increasing antioxidant activity. Nivolumab significantly reduced serum testosterone levels, while hesperidin administration increased serum testosterone levels. Additionally, nivolumab interrupted this pathway by reducing the expressions of PI3K, AKT, and MTOR in testicular tissue. On the other hand, hesperidin application increased PI3K, AKT, MTOR expressions and brought them closer to the control level. Additionally, while nivolumab decreased PD-1 expression levels, hesperidin did not cause a change in PD-1 expression levels. Histopathological analysis determined that nivolumab caused damage to the testicular tissue, and this damage was alleviated by hesperidin. In immunofluorescence analysis, severe cytoplasmic 8-hydroxyguanosine (8OhDG) and Caspase-3 expressions were detected in spermatocytes. It was observed that hesperidin application alleviated these expressions. Taken together, nivolumab caused oxidative damage in rat testicular tissue, and hesperidin provided significant protection against the damage caused by nivolumab in testicular tissue with its antioxidant and anti-apoptotic effects. Keywords: Nivolumab, Testis, Hesperidin, Monoclonal antibody, PD-1