Chronic scrotal heat stress induces dose-dependent collapse of male sexual behavior in mic

Journal of Animal Behaviour and Biometeorology - WoS (ESCI), Q2

Author: Đặng Ngọc Phúc - Trường Đại học Đông Á

Abstract:

Scrotal hyperthermia is known to impair male reproductive physiology. However its dose- and time-dependent effects on copulatory behaviors have not been fully characterized. This study aimed to systematically quantify the longitudinal effects of chronic scrotal heat stress at moderate (37°C) and severe (40°C) temperatures on the sexual behavior of male mice and correlate these behaviors with testicular mass. Male ICR mice were randomized into control, moderate-heat (H37), and severe-heat (H40) groups. Copulatory behaviors, including mounting, intromission, and ejaculation parameters, were assessed weekly for seven weeks. Testicular and body weights were measured at the conclusion of the study. Control mice maintained stable sexual behavior throughout the study. In the H37 group, progressive impairment was observed starting at week three; with increasing mount, intromission, and ejaculation latencies and decreasing, whereas the frequencies of these behaviors correspondingly decreased over the seven-week period. The H40 group exhibited more severe and rapid deterioration. Behavioral latency increased sharply through week five before all copulatory activities,—including mounting, intromission, and ejaculation,—ceased entirely from week six onward. These behavioral deficits were linked to a significant, dose-dependent reduction in testicular mass. Chronic scrotal heat stress impairs male sexual performance in a dose- and time-dependent manner, ranging from gradual functional decline to complete behavioral collapse. This study established a robust murine model with sensitive behavioral endpoints that is useful for investigating the pathophysiology of heat-induced reproductive dysfunction and for evaluating potential therapeutics.