Modulation of testicular macrophage activity by collagenase.

Testicular macrophages (TMs) are located in the interstitial tissue of male gonad. These phagocytic cells take part in forming the organ-specific functional blood-testis barrier and participate in the regulation of the local hormonal balance. In the present study, we isolated TMs from testicular tissues using previously described methods--mechanical (M-TMs) or enzymatic, by treatment with collagenase (E-TMs) and then we studied production by these cells of several cytokines and reactive oxygen intermediates (ROI's). Similarly treated oil-induced peritoneal macrophages (PMs) were used as control cells. PMs had a higher baseline level of production of TNF-alpha, IL-6, IL-10 and IL-12 than M-TMs and collagenase treatment increased the production of these cytokines (except IL-12) by both cell populations. This effect was significantly more expressed in TMs. In contrast to PMs, TMs produced little ROI's when stimulated by zymosan. We conclude that in the case of local inflammation in the testis, ROI-negative TMs do not contribute to the tissue damage and instead may direct the local immune response into humoral pathway.