Comparative Study on Different Recovery Periods of the Spermatogenic Dysfunction Mouse Model Induced by Cyclophosphamide

Abstract

ObjectiveTo compare and evaluate the improvement degree of spermatogenic dysfunction mice at different recovery periods after cyclophosphamide modeling.MethodsForty-eight male ICR mice aged 4-5 weeks with the body weight of approximately 18-20 g were randomly divided into three control groups and three model groups, with 8 mice in each group. Each mouse of three model groups was intraperitoneally injected with 60 mg/kg cyclophosphamide continuously from the 1st to 7th day of the experiment, while each mouse of three control groups was intraperitoneally injected with the corresponding volume of normal saline. Then these mice were continued to be fed for another 7, 14 and 21 days after cyclophosphamide injection, respectively. A corresponding control group was set for each model group. The mice in each group were sacrificed after blood collection through orbital veins at corresponding time points. Testis, epididymis and seminal vesicle were taken and weighed, and their reproductive organ indexes were calculated. Histopathological changes of testis and epididymis were compared after HE staining.Sperm quality analysis was used to determine sperm-related indexes. Serum reproductive hormone content, testicular oxidative stress level and testicular signature enzyme activity were detected by ELISA and related kits.Results Compared with the control group, on the 7th, 14th and 21st day after cyclophosphamide treatment, the testicular index of mice in the model group decreased significantly (P<0.01). The epididymis index decreased significantly on the 7th and 14th day, and the seminal vesicle index decreased obviously on the 7th and 21st day (P<0.05). And the histopathological damage of testis and epididymis of the model group gradually alleviated over time. On the 7th and 14th day after cyclophosphamide treatment, the sperm count of the model group declined remarkably (P<0.01), the serum testosterone (T) level reduced (P<0.05), the malonaldehyde (MDA) content of testis increased significantly (P<0.01), the content of reduced glutathione (GSH) and superoxide dismutase (SOD) decreased obviously (P<0.05),the lactic dehydrogenase (LDH) activity of testis reduced obviously (P<0.05), the gamma-glutamyl transpeptidase (γ-GT) activity increased significantly (P<0.05), the latter two of which are important testicular signature enzymes. Therein on the 7th day after cyclophosphamide treatment, the sperm motility decreased significantly (P<0.001), the rate of sperm malformation increased obviously (P<0.05), the serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) increased notably (P<0.01). Nevertheless on the 21st day after cyclophosphamide treatment, the sperm-related indexes, the content of serum reproductive hormone, the level of testicular oxidative stress and the activity of testicular signature enzyme did not change significantly (P＞0.05).ConclusionThe reproductive toxicity in mice was more apparent on the 7th day after intraperitoneal injection with 60 mg/kg cyclophosphamide for seven days, at which time the more desirable spermatogenic dysfunction model of mice could be established. However, with the prolongation of the recovery period, the indexes of spermatogenic dysfunction in mice gradually recovered and approached the normal level on the 21st day after cyclophosphamide treatment.

Keywords

• cyclophosphamide
• spermatogenic dysfunction
• recovery stage
• icr mice