Interleukin-1 beta but not interleukin-1 alpha, induces acute inflammation-like changes in the testicular microcirculation of adult rats.

A number of inflammatory mediators and cytokines were injected locally into the testis of adult rats in order to test their ability to induce leukocyte accumulation and increased vascular permeability (as studied by a carbon labelling technique). Human recombinant interleukin-1 beta (IL-1 beta) caused increased vascular permeability and leukocyte migration. All the other factors studied--histamine, serotonin, bradykinin, interleukin-1 alpha (IL-1 alpha), and a partially purified interleukin-1 alpha-like factor (tIL-1) from rat testis--did not induce any acute signs of increased vascular permeability or inflammatory response after local injection. It is suggested that local production of IL-1 beta from testicular macrophages could be responsible for the inflammation-like changes that are seen in rat testes after treatment with human chorionic gonadotrophin.