Changes in Cytomorphology, Expression of Retinoblastoma Related Gene, and Superoxide Dismutase Enzyme Activity in Maize Cell Culture Exposed to Silver Nanoparticles

The ever-increasing use of silver nanoparticles (nAg) in various products necessitates investigation of the behavior of biological systems encountering these particles. In this paper, considering maize as a biological model, the effects of colloidal nAg (<;80nm) on its cell culture were investigated. For comparison purposes, silver nitrate was used as a representative of silver ion (Ag
⁺
). After stabilization of cell suspensions, they were treated with nAg and Ag
⁺
(1 mg/l), then cell suspension growth was measured and the microscopic analysis and a cell viability test were performed. In addition, the activity of superoxide dismutase (SOD) enzyme was explored. Owing to the key role of retinoblastoma-related protein (RBR) in cell cycle as well as in development and differentiation processes, the relative expression of ZmRBR1 was studied in nAg and Ag
⁺
exposure. Microscopic analyses revealed that cells in suspensions treated by nAg and Ag
⁺
were morphologically classified into five types: embryogenic; larvae-like; long; swollen; and polarized. The results showed an increase in percentages of large and live cells in the treated suspensions. Remarkably, we observed some cells which were differentiated into trichomes along with some stages of trichome development in the treated cell suspensions. Moreover, exposure to nAg and Ag
⁺
did not elevate the activity of SOD enzyme in the treated cells. Also, the relative expression of ZmRBR1 was slightly reduced in the treated cells. The findings of these experimentations indicated that nAg affected maize suspension-cultured cells in the same manner as Ag
⁺
.