Heparin can cause some complications in tissues when it is used for a long term therapy. Besides its beneficial effects, it may have some side effects.

In this study, we investigated the possible hematological and histopatholgical changes in rabbit tissues under long term (one month) and overdoses (1000 and 2000 IU/kg/day) heparin applications.

Group I was injected with serum physiologic and kept as control while Group II and Group III were injected with heparin as a dosage of 1000 IU/kg/day and 2000 IU/kg/day, respectively.

There was no significant differences between the average values of serum electrolytes and copper levels of two experimental groups and the control group while their serum zinc levels (4.54 ± 0.52 mg/ml and 4.72 ± 0.65 mg/ml) were significantly ( p<0.05) lower than the controls (5.75 ± 0.72 mg/ml). The hemoglobin level of the Group III was significantly lower than both Group II and the control.

In this study, it is investigated the possible histopathological changes in rabbit kidneys under long term and overdoses heparin applications. In the light microscopic observations of kidney tissues of Group II and III were observed renal lesions in glomerular and tubular structures of cortex and medulla. Focal segmental necrotising glomerular lesions were seen. Cortex contained dilated distal tubules lined by flattened cells. Some of the proximal tubuler cells had no nuclei and their cytoplasm appeared pale stained. Some lesions observed to involve the cells of the medullary ray and outer stripe of the medulla. Interstitial spaces contained inflammatory infiltrated cells.

These results suggested that long term and overdose heparin application have degenerative side effects on renal tissues and on serum zinc level.