EFFECT OF CHLOROQUINE ON THE FORMATION OF TIGHT JUNCTIONS IN CULTUREDIMMATURE RAT SERTOLI CELLS

Adjoining immature Sertoli cells in the seminiferous epithelium form a tight junctional complex leading to the development of the blood-test is barrier. Protease and antiprotease activities have been implicated in the process of formation of tight junctions. Here, we report the ef fect of chloroquine, an antimalarial drug with antiprotease activity, on the development of intercellular tight junctions in cultured immatu re rat Sertoli cells. For positive control, the classical lysosomotrop ic agent ammonium chloride was used. Sertoli cells were seeded in seru m-free defined medium at a density of 3 x 10(6) cells/0.64-cm(2) well on Matrigel-covered Millicell-HA filters. Chloroquine at concentration s ranging from 25 to 100 mu M was added to the outer chamber of the bi cameral system on either day 1 or 7 of the culture. The formation of t he tight junction was monitored by the measurement of the transepithel ial resistance (TER) at 24-hour intervals using an impedance meter. TE R in untreated controls was 50 ohms/cm(2) on day 1, it increased progr essively to 80 ohms/cm(2) by day 7 and plateaued until day 12. The cel ls treated from day 1 with chloroquine also showed a dose-dependent pr ogressive increase in TER until day 9, reaching 225 ohms/cm(2) in cell s treated with the 100 mu M concentration. In comparison to controls, the increase in TER was significantly higher. In cells treated with ch loroquine starting from day 7 of culture onwards, there was no observa ble difference in TER from the untreated control. These observations d emonstrate that chloroquine and ammonium chloride increase the TER of immature Sertoli cells in the bicameral chamber.