Factors Affecting Arterial Supply of Testis Under Experimental Conditions.

The presence of well defined anastomoses between the 3 arteries of the testis at the cauda epididymidis has been repeatedly demonstrated by morphological studies. The testicular atrophy, however, that has followed experimental and clinical ligation of the internal spermatic vessels, indicates the need of an investigation of factors affecting the arterial supply of the testis. It has been shown that after ligation of the internal spermatic artery and vein, the testis undergoes sloughing or complete atrophy while the epididymis remains normal. This difference toward ligation became a primary consideration in the present investigation. The tunica albuginea covering the epididymis is thinner and less resistant than the part covering the testis. Was the congestion in the testis following ligation due to the unyielding nature of its fibrous investment? A characteristic reaction associated with ligation of the internal spermatic vessels is a sudden appearance of firmness or so-called “stone-hardness” in the testis, and this stone-hardness is remarkably uniform in degree. Our objective was to duplicate this increased tension experimentally and test the degree of penetration of injection-media under these conditions. Hill, while injecting the human testis, observed that the organ became firm when perfused with normal salt solution under a pressure of 60-80 mm. of mercury. This increase in tension occurred with a pressure below the normal systolic pressure, and Hill believed that the phenomenon was due to an extravasation of fluid between the endothelial cells of the capillaries, induced by the rapid death of these cells. In the present work we have been able to duplicate the “stone-hardness” of the testis by means of saline perfusions. A control condition which will here be designated as “normal tension” was maintained with saline perfusions of a duration of 4 minutes, under a pressure not exceeding 120 mm. of murcury. A degree of tension, which will here be used as the standard of “increased tension”, was produced by saline perfusions under the same pressure prolonged to 20 minutes. This increased tension corresponds to the stone-hardness found in the living testis after ligation of the internal spermatic vessels.