Objective: 

Paraquat (1,1'-dimethyl-4,4'-bipyridinium; PQ), a non-selective contact herbicide, is highly toxic to humans. Kidney is one of major target organs affected during PQ poisoning. Dexamethasone (Dexa) has anti-inflammatory effects used in PQ poisoning. The aim of this study was to investigate hemodynamic and immunohistochemical effects of Dexa treatment in acute PQ poisoning on rat kidney.

Methods: 

Adult male Sprague Dawley rats (240–270 g) were divided as: 1) Control, 2) Dexa: 100 mg/kg/ip, 3) PQ: 25 mg/kg/ip 4) PQ+Dexa groups. Total blood volume (TBV), mean arterial pressure (MAP) and heart rate (HR) were recorded during the experimental period. Kidney samples were obtained and were fixed in 10% formalin solution. Routine paraffin tissue procedure was executed and paraffin blocks were stained with Hematoxylin-Eosin. Anti-cyclooxygenase-1 (COX1), anti-cyclooxygenase-2 (COX2), anti-angiotensin converting enzyme (ACE), anti-aquaporin-1 (AQU-1), anti-vascular cell adhesion molecule (VCAM) primary antibodies were used for immunohistochemical examination. Immunoreactivities were scored as mild, moderate or severe, and results were evaluated comparatively using ANOVA statistical test.

Results: 

TBV was increased when 10 and 20 min values were compared in PQ group. MAP value at 10 min was significantly increased especially in Dexa group. HR was also increased in all groups compared with the control group at the 120 minute. Immunoreactivies were observed as moderate/severe in the control group, mild in Dexa group whereas it was severe in the PQ group. Immunoreactivities were observed as moderate in group PQ + Dexa, as closer or the same in the control group.

Conclusions: 

The decreasing effect of Dexa and increasing effect of paraquat on TBV were found to be related to acute changes in the tissue level.