O-17: Human Ovarian Tissue Xenotransplantation Application in Drug Discover

Background: Reproductive toxicity studies (RTS) represent an important part of pre-clinical safety evaluation of any drug development process for human consumption. It is mandatory requirement that RTS must be completed before any drug can be administered to women of childbearing age. Therefore, at first segment of toxicity check the toxic effect of the drug on fertility must be tested on non-clinical studies. In line with it, segment II and III are performed to detect effects on embryonic and post-natal development. Materials and Methods: Two random agents of AX384 and CR21 were received for evaluation blindly. We used our previously introduced human-to-SCID mice (dorsal muscle) ovarian tissue xenotransplantation model as a potential for preclinical RTS. Therefore, xenotransplanted animals were let to recover for the duration of four weeks and proposed dose of each agent was administered using proposed route of administration. Animals in each study group were sacrificed at different time points after drug administration and the grafts were recovered (No=50±6) for further evaluations. Samples were processed for immunonohistochemical evaluated. Number of existing and apoptotic ovarian follicles (using Active caspase-3) was counted in each sample. Follicles were also collected using laser capture microdissection for microarray-based gene expression profiling. Results: While a single dose administration of AX384 presented a sever toxicity demonstrated by follicular loss evaluated on day 7 (8.1 ± 1.2 vs. 16.4 ± 0.8 %, p<0.01) and apoptotic follicles in general (12 ± 5.3 % vs. 3.5 ± 2.2 %, p<0.05), CR21 had very moderate follicular toxicity effect (p>0.1). From 9100 targeted analyzed genes, 112 were discriminated in samples collected one week after one dose administration of AX384 and 53 genes in CR21 group. In general Discriminating genes were mostly those involved in stress responses, apoptosis, cell cycle control and DNA repair response. Conclusion: Our experiment approved the ability of human ovarian tissue xenografting model as a new in vitro testing approach to predict chemical toxicity in drug development procedure. However, further studies are still ongoing till obtaining adequate data to establish a standard protocol.