The revelation of the mechanism of the post-fertilization effect of paternal exposure on endocrine disruptors on the development and fertilizing capacity of the male offspring.

2020 Fiscal Year Research-status Report

• Project/Area Number: 20K18092
• Research Institution: Tottori University
• Principal Investigator: ツナピ パナイオタ 鳥取大学, 医学部附属病院, プロジェクト研究員 (50767431)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: male infertility / endocrine disruptor / sperm / testis / perfluorinated chemicals

Outline of Annual Research Achievements

The animal model of exposure to low dose of perfluorooctanesulfonic acid (PFOS) for the adult rats has been created. The rats received intraperitoneal injections of PFOS for 12 weeks. Their body weight was significantly decreased compared to the Control group.
The animal model of exposure to both low and high doses of PFOS for the pre-pubertal age rats(4 week-old) had as a result all the treated animals to die before completing the treatment period of 12 weeks. During their treatment period, their body weight was gradually decreasing day by day. Some of the animals had seizures and incidents similar to heart attack.
PFOS appears to have severe effects on the well-being of the animals.

Current Status of Research Progress

3: Progress in research has been slightly delayed.

Reason

Perfluorooctanesulfonic acid (PFOS)was not available in Japan, therefore we had to wait for some time until delivered from abroad. Because of the corona virus pandemic there was a delay. Additionally, the doses of PFOS were lethal for the pre-pubertal age rat model, which had as a result to reconsider the doses of PFOS and recreate the model with lower doses. This is also another reason for the slight delay.

Strategy for Future Research Activity

Mating studies are planned. Female rats will be evaluated for pregnancy, the number of pups per female rat delivered will be listed and the body weight of the pups will be recorded daily. After the mating studies, the reproductive organs of the male rats will be obtained under general anesthesia, as well as sperm will be aspirated from the epididymal cauda and sperm parameters will be evaluated. Blood and urine samples will also be collected for further analysis. The parameters will be measured as described in the protocol.

Causes of Carryover

Because of the delay on the delivery of the chemicals required to create the animal model, the beginning of the study delayed. Therefore the animal study, due to unexpected death of the animals in the per-pubertal age groups has been transferred for the next fiscal year. The remaining amount of money needs to be transferred for the smooth process of the study.