Silica nanoparticles (SiNPs) are among the non-toxic nanoparticles (NPs) that have magnetic capabilities. It is
hypothesized that SiNPs may be able to reduce toxic effects exerted by a mixture of lead (Pb) and mercury (Hg) in
African catfish Clarias gariepinus. The in vitro magnetic potential of SiNPs to absorb Pb and Hg was tested. Fish (N
=240) were divided into four groups in triplicates for 30 days. The first group served as control and the second
group (SiNPs) was exposed to 1/10 of 96 h LC50 of SiNPs (14.45 mg/L). The third group (HMM) was exposed to
1/10 of 96-h LC50 of a mixture of mercury chloride (HgCl2) and lead chloride (PbCl2) equal to 0.04 mg/ L and
23.1 mg/L. The fourth group (SiNPs+HMM) was exposed to a suspension composed of SiNPs, HgCl2, and PbCl2
at the same concentrations as the third group. Results showed that fish exposed to heavy metals revealed the
following consequences; a significant decrease in hematological, immunological (complement-3 and nitric
oxide), and antioxidants (total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase)
indices, down-regulation of IL-1β, IL-8, TGF-β, NF-κβ, HSP70, and Hepcidin genes, the highest mortality rate
(48.33%), higher values of alkaline phosphatase, alanine, and aspartate aminotransferases, urea, creatinine, and
branchial malondialdehyde, marked up-regulation of CC chemokine and CXC chemokines, and high HMs resi
dues levels in muscles. Extensive pathology showed degeneration with diffuse vacuolation of hepatopancreatic
cells and hemorrhage in the HMM group. Interestingly, the exposed group to SiNPs and HMM demonstrated a
decline of HMs concentration in fish muscles and modulated the abovementioned parameters with the regen
eration of histological alterations of liver and gills. Based on the study outcomes, we highlight the importance
and the safety of SiNPs as a novel aqueous additive to alleviate HMs toxicity and recommend using SiNPs for
enhancing fish performance for sustaining aquaculture without adverting safety of human health by their little
accumulation in muscular tissue. |
