Influence of the long-term exposure to tartrazine and chlorophyll on the fibrogenic signalling pathway in liver and kidney of rats: the expression patterns of collagen 1-α, TGFβ-1, fibronectin, and caspase-3 genes

Colouring agents are highly present in diverse products in the human environment. We aimed to elucidate the fibrogenic cascade triggered by the food dyes tartrazine and chlorophyll. Rats were orally given distilled water, tenfold of the acceptable daily intake of tartrazine, or chlorophyll for 90 consecutive days. Tartrazine-treated rats displayed a significant rise (p < 0.05) in the mRNA levels and immunohistochemical localization of the renal and hepatic fibrotic markers collagen 1-α, TGFβ-1, and fibronectin and the apoptotic marker caspase-3. Moreover, a significant increment (p < 0.05) in the levels of AST, ALP, creatinine, and urea was evident in both experimental groups but more significant differences were noticed in the tartrazine group. Furthermore, we found a marked increment in the MDA level and significant declines (p < 0.05) in the levels of the SOD, CAT, and GSH enzymes in the kidney and liver from tartrazine-treated rats. The histological investigation reinforced the aforementioned data, revealing hepatocytes with fibrous connective tissue proliferation, apoptotic hepatocytes and periportal fibrosis with tubular necrosis, and shrunken glomeruli and interstitial fibrous tissue proliferation. We concluded that, even at the exposure to high concentrations for long durations, chlorophyll exhibited a lower propensity to induce fibrosis, apoptosis, and histopathological perturbations than tartrazine.