Testicular thermoregulation with respect to spermatogenesis and contraception.

There has been some evidence that a short heating exposure of the testicles can lead to temporary sterility. However, little attention has been paid to analyzing the temperature/time pattern throughout the testicle and how metabolism and blood perfusion affect the temperature profile. We use the Penne bioheat equation that accounts for the elements of conduction, perfusion, and metabolism along with the COMSOL Finite Element Method for the analysis of this thermoregulation problem. Typically, the testicles were modeled as two uniform spheres and exposed to an increase in surface temperature of 42 °C for 30 min. We found that heat produced by tissue metabolism had a minor effect on the temperature pattern. However, blood flow from the core (at 37 °C) could prevent the region where the testicles touch each other from reaching the target temperature of 42 °C. Further, we found that for animals, as rodents and monkeys that are used for contraception studies, the temperature distribution on heating testicles is much more uniform than for humans. Thus, extrapolation results from animal models to humans should be done with caution.