Workers involved in mining activities are exposed to crystalline
silica, which leads to constant pulmonary inflammatory reactions and severe oxidative damage, resulting in
silicosis. In this work, we aimed to evaluate inflammatory and oxidative stress parameters as potential early
biomarkers of effect to assess crystalline
silica toxicity in workers who had occupational exposure during mining. We enrolled 38 workers exposed to crystalline
silica (WECS), 24 individuals with
silicosis (IWS), and 30 occupationally unexposed workers (OUW), a total of 92 participants. The WECS were divided into 2 groups, according to the time of exposure: 19 workers with 1-15 years of occupational exposure (WECS I) and 19 workers with >16 years of occupational exposure (WECS II). The inflammatory parameters assessed were
L-selectin, β-2
integrin, and
intercellular adhesion molecule-1 (ICAM-1)
surface protein expression in lymphocytes and monocytes,
complement C3 and C4,
high sensitivity C-reactive protein (
hsCRP), and
adenosine deaminase (ADA) in serum. Plasma levels of
malondialdehyde (MDA) and serum levels of
vitamin C were determined as
biomarkers of oxidative stress. Biochemical and hematological parameters were also investigated.
L-selectin surface protein expression was significantly decreased in the WECS II group (p < 0.05), indicating the importance of this immune system component as a potential marker of crystalline-
silica-induced toxicity. The MDA levels were significantly increased in the WECS I, WECS II, and IWS groups compared to the OUW group (p < 0.05).
Vitamin C levels were decreased, while C3,
hsCRP, ADA, and
aspartate aminotransferase (AST) levels were increased in the IWS group compared to the OUW group (p < 0.05).
Glucose and
urea levels were significantly higher in the WECS I, II, and IWS groups compared to the OUW group (p < 0.05). Negative partial association was found between
L-selectin and time of exposure (p < 0.001), supporting the relevance of this
biomarker evaluation in long-term exposure to crystalline
silica. Significant associations were also observed among inflammatory and oxidative stress
biomarkers. Therefore, our results demonstrated the relevance of
L-selectin as a potential peripheral
biomarker for monitoring crystalline
silica-induced toxicity in miners after chronic exposure, before
silicosis has developed. However, more studies are necessary for better understanding of the use
L-selectin as an early
biomarker in exposed workers.