Physiological, biochemical, apoptosis-linked gene expression, and histopathological insights in Nile catfish subjected to toxicity by magnetite nanogel.

The target of this novel work is to assess the immunosuppression, genotoxicity, histopathological alterations, and cumulative mortality induced by acute toxicity of magnetite nanogel (MNG) in Nile catfish. Furthermore, a subsequent 10-day depuration period is adopted to estimate the restoration of those disturbed indices. Nile catfish (n = 180) were allotted into four groups and exposed to different concentrations of MNG (0, 1/10, 1/8, and 1/5 96-h LC₅₀). The outcomes displayed a remarkable concentration-dependent decline in the immune indices level (LYZ, NO, and MPO). The gene expression of antioxidant (SOD) and apoptosis-regulatory genes (MAPK3 and JNK) was upregulated in MNG-exposed fish. Histopathological disruptions in the tissue architecture of gills and intestines were also evident in MNG-exposed groups. Interestingly, after a 10-day depuration period, marked improvement in the level of immune response mediators and gene expression of apoptotic genes was evident in all experimental groups, particularly at 1/10 of LC₅₀. Overall, exposure to higher concentrations of MNG (1/5 and 1/8 of LC₅₀) exerts multiple adverse influences on the Nile catfish, which were less pronounced at 1/10 of LC₅₀. Surprisingly, a subsequent 10-day recuperation time was adequate for alleviating those impairments, with the maximum improvement in the Nile catfish exposed to 1/10 of LC₅₀.