Investigation of TNFα Level and Metallothionein Gene Expression in Livers of Rats Exposed to Dietary Aluminum

Aluminum chloride is a chemical compound widely used in both pharmaceutical and industrial sectors. The present study aimed to assess the effect of aluminum chloride on TNF levels and metallothionein gene expression in rat livers. A total of 16 Wistar rats were used as an experimental model and assigned to four groups (n=4). The treated groups received aluminum chloride (Sigma/USA) at a dose of 25g/kg body weight via a feeding tube as follows: group 1: Non-treated rats as the control group, group 2 were treated with aluminum chloride for 8 weeks, group 3 were treated with aluminum chloride for 12 weeks, and group 4 received aluminum chloride for 16  weeks. The TNF-α was measured in liver tissue using an enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry and real-time polymerase chain reaction (RT-PCR) were used to analyze metallothionein gene expression in rat liver. To estimate TNF levels, the results revealed that levels were considerably higher (P˂0.01) in all experimental groups, especially in group 4 which underwent treatment for  16 weeks (401±22.1 ng/ml), as compared to that in the control group. For the immunohistochemistry assay, a gradient intensity of staining for liver tissue was observed, ranging from zero staining in the control group to moderate, medium, and high staining in the experimental groups after 8, 12, and 16 weeks of aluminum chloride treatment, respectively. The greatest amount of methylothionine expression was observed in the livers of group 4 which received aluminum chloride for 16 weeks (15.5-fold), with a significant difference (P˂0.01) from the other experimental groups. In both immunohistochemical and RT-PCR experiments, aluminum administration had a substantial influence on TNFα levels and metallothionein expression in rat livers.