Evidence for tissue-specific toxicity of malathion by biochemical biomarkers and histopathological indexin two weeks-treated Wistar rats

Malathion (MAL), a kind of organophosphate pesticide (OPs), is one of the oldest phosphoric pesticides used for both domestic and commercial agricultural purposes. However, it possesses adverse effects and organ-specific toxicity for the heart, kidney, and other vertebrate organs. The exact effects of the short-term toxicity of MAL on lipid peroxidation, antioxidant activity, and pro-inflammatory cytokines have not been sufficiently elucidated yet.

We evaluated lipid peroxidation (MDA level), antioxidant activity [superoxide dismutase (SOD) and catalase (CAT)], tumor necrosis factor alpha (TNF-α), and Interleukin-1 beta (IL-1β) in different tissues of MAL-treated Wistar rats, at doses of 50, 100, and 200 mg/kg.

After 14 days of exposure, CAT and SOD activities and MDA level increased in most tissues. Based on the histopathological results, the liver, kidney, and heart were the most affected, while the testes and lungs showed no damage. Also, increased TNF-α was measured as an inflammatory cytokine compared to untreated rats. IL-1β levels showed a dual response to the toxic effects of MAL, such as an increase in testis, kidney, and lung tissues and reduced in liver, heart, and blood tissues.

The present findings reinforce the concept that MAL can cause tissue-specific damage while enhancing the activity of antioxidant enzymes and reducing cytokine levels.