Comparative haemato-immunotoxic impacts of long-term exposure to tartrazine and chlorophyll in rats

The haemato-immunotoxic effects of the food colourants tartrazine and chlorophyll were evaluated. Thirty adult Sprague Dawley rats were distributed into three groups and orally administered water, tartrazine (1.35 mg/kg), or chlorophyll (1.35 mg/kg) daily for 90 days. Erythrogram and leukogram profiles were evaluated. The lysozyme, nitric oxide, phagocytic activity, and immunoglobulin levels were measured. Histological and immunohistochemical evaluations of splenic tissues were conducted. Changes in the interleukin (IL) 1β, 6, and 10 mRNA expression levels were assessed. In the tartrazine-treated rats, a significant anaemic condition and marked leukocytosis were observed. Both the innate and humoural parameters were significantly depressed. Different pathological lesions were observed, including red pulp haemorrhages, vacuolation of some splenic cells, focal hyperplasia of the white pulp, and capsular and parenchymal fibrosis. A marked increase in vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (e-NOS) immunolabelling was evident. Marked upregulation of IL-1β, IL-6, and IL-10 was recorded. In contrast, the chlorophyll-treated rats showed minimal haemato-immune responses. These results indicate that tartrazine exerts haematotoxic and immunotoxic effects following long-term exposure, whereas chlorophyll is a less hazardous food colourant.