Changes in the permeability of the testicular capillaries and of the 'blood-testis barrier' after injection of cadmium chloride in the rat.

Abstract

SUMMARY Blood flow, capillary permeability and the entry of rubidium into the testis, epididymis, skeletal muscle and brain of male rats were examined within 6 hr. of giving an s.c. injection of cadmium chloride (3 μmole/100g. body wt). Sapirstein's (1958) indicator fractionation technique was used to measure blood flow with [125I]iodoantipyrine and simultaneously capillary permeability and rubidium uptake were assessed using 131I-labelled human serum albumin and [86Rb]rubidium chloride respectively. Blood flow in the testis and the initial segment of the caput of the epididymis increased in the first 2 hr. after cadmium administration, returned to control levels at 3 hr., and thereafter sharply decreased. Labelled albumin began to accumulate in extravascular compartments 3–4 hr. after cadmium; in the head of the epididymis this increase in capillary permeability appeared earlier than in the testis and preceded the fall of blood flow. The limited transport of rubidium into the seminiferous tubules was again observed and used as a criterion of tubular integrity. The uptake of 86Rb by the testis increased within 2 hr. of giving cadmium and thus preceded the extravascular transport of albumin from the capillaries. This is the earliest indication of cadmium damage to the tubules so far reported. There were no systematic changes in these parameters in the rest of the epididymis, skeletal muscle or brain.