Protective Effect And Mechanism Of Melatonin On Cisplatin-induced Ovarian Damage In Mice

Background Cisplatin(CP)is one of the most powerful antitumor agents and is widely used against various malignancies liver,lung,colorectal and cervical cancers.However,dose-related toxicity is considered to be one of the natural factors limiting the administration of cisplatin.Cisplatin has now been shown to have side effects such as toxicity to the kidneys,ears and hearing,liver and heart,in addition to causing changes in fertility,organ structure,sex hormones and function,and even leading to loss of fertility,thus reducing quality of life.Melatonin(MT)has been shown to have more beneficial effects on ovarian function due to its antioxidant,inflammation,autophagy and apoptosis modulating functions.In addition,melatonin has been found to exert anticancer effects by inhibiting cancer cell proliferation and regulating mitochondrial function.In this study,we aimed to investigate the effect of MT on CP-induced ovarian injury and its molecular mechanism by establishing an animal model of cisplatin-induced ovarian injury.Methods Seven-week-old female C57BL/6J mice were selected for inclusion in this study,and after one week of acclimatization,they were randomly divided into the following four groups(10 mice per group): control(Con),CP,CP+MT and MT groups.For the CP treatment group,mice were injected intraperitoneally with 2 mg/kg CP,repeated every other day(dissolved in isotonic saline)until day 21.Mice in the control group were injected intraperitoneally with an equal amount of 0.9% saline.For CP+MT treatment,mice were pretreated with 30 mg/kg of MT by intraperitoneal injection 3days prior to CP treatment,the CP injection dose was the same as that of the CP group.The MT group was injected with 30 mg/kg intraperitoneally daily.After 21 days,the mice were executed by decervicalization under anesthesia.Mouse ovaries were collected and part of them were stored frozen at-80°C for protein immunoblotting(WB)to detect the expression of TOM20、OPA1、Mitofilin and other proteins.The other part of the ovaries were fixed in 4% paraformaldehyde and paraffin-embedded.The expression of AMH,BMP15 and ovarian inflammatory factor IL-18 was examined using immunohistochemistry.Results Compared with the control group,ovarian reserve and follicle development-related proteins(AMH,BMP15)were significantly reduced in the CP group,and protein expression increased after the addition of melatonin treatment(P <0.05).decreased cell cycle-related protein CDC2 and increased apoptosis caused by CP treatment also returned to normal after the addition of melatonin treatment.In addition,CP resulted in increased ovarian inflammatory factors IL-1β and IL-18 in mice(P <0.05),which were normalized by melatonin.In addition to these effects,CP disrupts mitochondrial function in the ovaries,such as abnormal expression of mitochondrial dynamics-related proteins DRP1 and Fis1,which are restored to normal after melatonin treatment.Finally,the expression of MAPK pathway-related proteins P-ERK,P-JNK,and P-P38 was also found to be significantly elevated in the CP-treated group(P < 0.05),and no significant abnormalities in the pathway proteins were observed after melatonin treatment.Conclusion Under cisplatin exposure conditions,ovarian function was impaired in mice with a significant decrease in reserve function,cell cycle arrest,increased apoptosis and inflammatory factors,and impaired mitochondrial function,a process that may be related to the MAPK pathway,and melatonin could protect ovarian function in mice by decreasing MAPK pathway-related proteins.