Effect of L-Arginine and L-NAME treatments on polymorphonuclear leukocytes and mononuclear cells influx during tumor growth.

Purpose: Evaluate polymorphonuclear leukocytes (PMN's) and mononuclear cells (MN's) involvement in the Ehrlich s solid tumor (ET) growth.

Methods: 90 Swiss mice were inoculated with 10(7) tumor cells (sc), distributed in three groups and treated once a day, via intraperitoneal (ip), with 0.1ml of diluent, L-Arginine (20mg/Kg) or L-NAME (20mg/Kg). After 7, 15 and 30 days of treatment, ten animals of each group were euthanized, the tumor mass was removed, processed and fixed for HE. Later, a morphometric analysis of the total area, parenchyma, necrosis, tumor stroma and PMN's leukocytes and MN's cells influx was performed.

Results: The L-Arginine treatment increased PMN's influx in the initial stage, whereas L-NAME reduced it. Our data suggests that NO effect on PMN's migration is dose-dependent. On the other hand, the MN s cells influx was reduced by L-NAME treatment at all evaluated periods and at the same periods an increase in tumor growth was observed.

Conclusion: At initial stages of tumor implantation, both PMN's leukocytes and MN's cells act together to control ET development.