Exploring the effects of naringenin on cell functioning and energy synthesis in the hippocampus of male Wistar rats with chronic tinnitus, by examining genetic indicators such as Bax, Bcl-2, Tfam, and Pgc-1α.

ABSTRACT

BACKGROUND: The pivotal factors, including neural plasticity, oxidative stress, neuronal inflammation, and apoptosis, play a significant role in the pathogenesis of tinnitus. The balance between Bax/Bcl-2 genes is an important factor in determining the rate of apoptosis. Pgc-1α and Tfam genes are fundamental regulators of mitochondrial biogenesis. Naringenin possesses significant antioxidant, neuroprotective, anti-inflammatory, anti-apoptotic, and antiviral properties, and its compounds are effective on cell signaling pathways. AIMS: In light of the aforementioned information, we endeavored to evaluate the impact of naringenin on the expression levels of Bax, Bcl-2, Pgc-1α, and Tfam genes in the hippocampus of male Wistar rats with chronic tinnitus. MATERIAL AND METHODS: To demonstrate the existence of tinnitus, all rats were instructed to complete an "active avoidance test" utilizing a conditioning box. The expression levels of genes mentioned above were assessed using real-time PCR. RESULTS: The sodium salicylate at a dosage of 350 mg/kg showed an upregulation in the expression level of Bax and a downregulation in the expression level of the Bcl-2 gene (p < 0.001). Furthermore, the sodium salicylate displayed significantly higher expression levels of Tfam and Pgc-1α (p < 0.001) genes. The naringenin, at a dose of 100 mg/kg, led to a decrease in Bax gene expression (p < 0.05) and an increase in Bcl-2 gene expression (p < 0.05). On the other hand, naringenin restored the expression level of both Tfam (p < 0.001) and Pgc-1α (p < 0.01) genes. CONCLUSIONS: Our research findings demonstrate that sodium salicylate-induced tinnitus leads to enhanced apoptosis and mitochondrial biogenesis within the hippocampus. Additionally, our evidence recommends that naringenin can reduce apoptosis effectively and maintain a balanced mitochondrial state.