Long-term Effects Of Cyclophosphamide On Gonads In Boys And Protection Of GnRH Antagonist In Pubertal Rats

As a cytotoxic alkylating agent,cyclophosphamide(CPA)is a commonly used anti-tumor drug and immunosuppressant in clinical practice.It is widely used in the treatment of various solid tumors and autoimmune diseases.It is one of the important therapeutic drugs for children with acute lymphocytic leukemia and severe systemic lupus erythematosus including lupus nephritis and nephritis.However,due to its damage to its own cells,it has certain side effects,especially gonad damage.With the continuous improvement of the long-term survival rate of childhood tumors and some serious autoimmune diseases[this part of the survivors into adulthood,the quality of long-term life,especially the influence of gonads,has gradually attracted more and more attention from both doctors and patients.The study found that the smaller the age of the long-term gonadal histological changes,the smaller the damage,suggesting that it is an effective protective method to prevent the gonads from being damaged by anti-tumor drugs and to make the germ cells proliferate and differentiate in an undifferentiated state.Therefore,the use of drugs to specifically target the pituitary gland axis will likely protect the gonads after chemotherapy.Gonadotropin-releasing hormone antagonists(GnRH antagonists)can directly cause rapid inhibition of the gonadal axis by competitively blocking the pituitary GnRH receptor.Therefore,this study conducted a long-term follow-up study of children who had received cyclophosphamide shock to analyze whether these children had gonad damage.Using a simulated cyclophosphamide to intervene in a male model of puberty to study whether GnRH antagonists can improve Long-term gonad damage and a preliminary mechanism of action.Part I A single-center clinical observation of the long-term effects of cyclophosphamide on gonads in boysObjective:To observe the long-term effects of intravenous cyclophosphamide shock therapy on testes in male children.Methods:A retrospective study of children with primary nephrotic syndrome,allergic purpura nephritis,systemic lupus erythematosus-associated nephritis treated with cyclophosphamide intravenous shock in children from Suzhou University from December 2003 to December 2013 The data were followed up for children who had been discontinued for more than 5 years,including the height,weight,the volume of the left and right testis,the age at which cyclophosphamide was started,the medication(cumulative dose and course of treatment),the age at follow-up,the time of withdrawal at follow-up,and the levels of sex hormones,testicular ultrasound.Results:A total of 53 male patients met the inclusion criteria,successfully followed up by telephone to 19 patients.The age of starting cyclophosphamide treatment was 7-16 years old,and the cumulative dose was 32-210 mg/kg.The age of follow-up was 16-25 years old,and the cyclophosphamide has been stopped for 5-11 years.A total of 9 patients who came to our hospital for physical examination,no abnormalities in testicular size via ultrasound,and no significant difference was measured in serum sex hormone levels(follicle stimulating hormone FSH,luteinizing hormone LH,testosterone,anti-Mullerian hormone AMH,inhibin B InhB,prolactin.)between adult patients and healthy men for the same age males.However,there was one case whose FSH level increased and InhB decreased.Conclusion:Cyclophosphamide intravenous pulse treatment has no obvious changes on testes for patients who have been stopped treatment for more than 5 years.Part ?GnRH Antagonist Improves Pubertal Cyclophosphamide-Induced Long-Term Testicular Injury in Adult RatsObjective:Gonadal injury following chemotherapy is of increasing importance with the continuous improvement of survival rates.The protection of gonadotropin hormone antagonist(GnRHant)in long-term adult survivors of adolescent cancers and some serious autoimmune diseases has not yet been evaluated.Methods:The present study was aimed at longitudinally exploring whether the GnRHant could alleviate testicular damage induced by cyclophosphamide(CPA)in a rat model.24 pubertal male Wistar rats were randomly divided into 4 groups.There were 6 rats in each group:(1)normal control group,(2)cyclophosphamide group,(3)GnRH antagonist+cyclophosphamide group,and(4)GnRH antagonist group.Cyclophosphamide was administrated at a single dose(100 mg/kg).GnRHant was started one hour prior to CPA injection and continued for four weeks(0.1 mg/kg,3 times a week)which lasted for 4 weeks.9 weeks after the end of intervention,just a spermatogenic cycle,the rat body weight and testicular weight,serum sex hormones(testosterone,anti-Mullerian hormone AMH,inhibin B)were compared.The morphological changes of testicular tissue were observed via light microscope.The expression of androgen receptor(AR)in the testis was analyzed by immunohistochemistry,RT-PCR and western blot.Results:Our results showed that body weight,histological injury,and AR expression in the testis were obviously improved in the GnRHant+cyclophosphamide group compared with cyclophosphamide group.However,testes weight and testicular hormones(anti-Mullerian hormone,inhibin B,and testosterone)did not significantly change.Conclusion:Our results indicate that the GnRHant administration before and after cyclophosphamide in pubertal rats can protect long-term testicular injury induced by cyclophosphamide via increased AR expression in the testes.