High-fat diet-induced obesity amplifies HSP70-2a and HSP90 expression in testicular tissue; correlation with proliferating cell nuclear antigen (PCNA)

Aims: Current study was conducted to uncover the effect of high-fat diet (HFD)-induced obesity on heat shock proteins 70-2a and 90 expression levels and to investigate the network between these proteins with PCNA expression, endocrine status of testicular tissue and nucleotide backbone damages. Main methods: For this purpose, 20 mature male Wistar rats were divided into two groups of control and HFDreceived obese animals (n = 10/group). After 8 weeks from obesity approval, the animals were euthanized. The expression levels of Hsp70-2a, Hsp90 and PCNA were analyzed by qRT-PCR and immunohistochemical staining techniques. The Leydig cell distribution/mm2 of interstitial tissue, serum level of testosterone, testicular total antioxidant capacity (TAC), and mRNA and DNA damage were investigated. Key findings: The obese (HFD-received) animals represented a remarkable (p < 0.05) increment in the mRNA levels of hsp70-2a and Hsp90, and the percentages of Hsp70-2a+ and Hsp90+ cells/seminiferous tubules with the same criteria. The PCNA mRNA level and the percentage of PCNA+ cells were decreased in the obese (HFDreceived) group. The obesity, significantly decreased testicular TAC and with no effect on the Leydig cell distribution, but by reducing their steroidogenic activity resulted in a remarkable (p < 0.05) reduction in serum testosterone level. Finally, severe mRNA and DNA damage were revealed in the obese (HFD-received) group. Significance: Therefore, considering massive testicular DNA damage in the obese (HFD-received) animals, we can conclude that an increased expression of Hsp70-2a and Hsp90 with no harmony with PCNA could not properly maintain the cellular DNA integrity and/or appropriately finalize the DNA repair process.

Automated summary

The study found that obese rats induced by HFD showed a significant increase in mRNA levels of Hsp70-2a and Hsp90, while the mRNA levels of PCNA and the percentage of PCNA+ cells were decreased in the obese group. Additionally, obesity led to a significant decrease in testicular TAC, resulting in a reduction in serum testosterone levels, along with cell DNA and RNA damage.