Establishment of safe and efficient infertile goat model using cyclophosphamide and its implications at the cellular and molecular level

Although several cell- and organoid culture-based systems have been developed to investigate the adverse effects of antineoplastic drugs, they have potential limitations, such as the loss of cellular structure and functions while in vitro culturing or genetic and phenotypic differences from their in vivo counterparts. Overcoming these challenges is crucial for cancer and fertility research. The development of a practicable workflow for generating infertile goat models represents a promising application for the future. For this, 12 healthy female goats were divided randomly into two equal groups (test and control). The test group (n = 6) received cyclophosphamide (CTX) intravenously at 30 mg/kg body weight in a single dose, and no treatment was given to the control group (n = 6). Blood samples were taken at different time points, i.e., 0-h, 6-h, 12-h, 18-h, 24-h, 36-h, 48-h, 72-h, 168-h, and 240-h post-CTX injection. The FSH receptor staining was done by the immunohistochemistry technique on formalin-fixed paraffin-embedded (FFPE) tissue sections. The samples chosen for IHC were based on the microscopic lesions observed in histopathology. The hemoglobin concentration (%) and total erythrocyte count (million/µl) were markedly reduced from 9.58 ± 0.37 (0 h) to 7.25 ± 0.28 (240 h, p < 0.05) and 24.28 ± 1.05 to 14.34 ± 0.99 (p < 0.001), respectively. However, TLC was the least affected among all the hematological parameters, and in DLC, neutrophil percentage was significantly (p < 0.001) increased at 6 h, and lymphocyte percentage was significantly decreased (p < 0.001). The serum urea and creatinine levels were increased post-CTX treatment, and serum estrogen (pg/ml) and progesterone (ng/ml) concentrations declined from 115.43 ± 19.10 (0 h) to 63.49 ± 8.98 (240 h) and 0.55 ± 0.07 (0 h) to 0.24 ± 0.03 (240 h), respectively. The histological analysis revealed a marked reduction in follicle numbers, suggesting POF post-CTX treatment. Furthermore, the expression analysis of glutathione peroxidase and CuZnSOD was down-regulated. The CuZnSOD expression was down-regulated from 674.64 at 0 h to 0.27 at 18-h post-treatment. However, the expression level of CuZnSOD was significantly (p < 0.001) up-regulated at 36 h of sampling. The expression of glutathione peroxidase was down-regulated from 0 to 24 h (p < 0.05). At the same time, that of Interferon γ and Interleukin 1β were down-regulated initially but up-regulated after 36 h with a 2.90-fold change at 168-h posttreatment for Interferon γ and a 9.96-fold change for Interleukin 1β. CTX induces POF by diminishing follicle numbers, hormonal synthesis, and damage at cellular and molecular levels. In conclusion, we were successfully able to establish a safe and efficient infertile goat model, which will be useful to understand the fundamentals and development of efficient antineoplastic and infertility treatments.