Voluntary exercise improves spermatogenesis and testicular apoptosis in type 2 diabetic rats through alteration in oxidative stress and mir-34a/SIRT1/p53 pathway

Abstract

Objectives: This research was designed to demonstrate the impact of voluntary exercise on sperm parameters including sperm count, morphology, motility, viability, testicular apoptosis, oxidative stress, and the mir-34a/SIRT1/p53 pathway in type 2 diabetic rats.

Materials and methods: 32 Wistar male rats were separated into four groups: control (C), voluntary exercise (VE), diabetic (D), and diabetic rats that performed voluntary exercise (VED). To induce diabetes, animals were injected with streptozotocin (35 mg/kg) after receiving a high-fat diet. The testicular protein levels of SIRT1 and P53, miR-34a expression, MDA, GPx, SOD, catalase, and sperm parameters were evaluated.

Results: Diabetes caused increased testicular MDA content, miR-34a expression, acetylated p53 protein expression, and the percent of immotile sperm (P<0.01 to P<0.001) as well as reduced testicular GPx, SOD and catalase activities, SIRT1 protein expression, and sperm parameters (P<0.05 to P<0.001). Voluntary exercise reduced testicular MDA content, miR-34a, and acetylated p53 protein expression compared with the D group (P<0.001), however, GPx, SOD, catalase activities, and sperm parameters in voluntarily exercised rats were elevated compared with diabetic rats (P<0.05 to P<0.001).

Conclusion: It seems that voluntary exercise has significant positive impacts that can be employed to reduce the complications of type 2 diabetes in the testis of male rats.

Keywords: Apoptosis; Oxidative stress; Sperm parameters; Type 2 diabetes; Voluntary exercise; miR-34a; p53.

Figure 1

Testicular (a) malondialdehyde (MDA) content (nmol/mg protein), (b) Glutathione peroxidase (GPX) activity (U/mg protein), (c) Superoxide dismutase (SOD) activity (U/mg protein) and (d) catalase activity (IU/mg protein) of control (C), voluntary exercise (VE), diabetic (D) and voluntary exercise diabetic (VED) groups. Data are presented as Mean±SEM (n=8). Comparisons were done by one-way ANOVA followed by Tukey’s post hoc test. Statistical differences between control and different groups: *; P<0.05, **; P<0.01, ***; P<0.001, statistical differences between diabetic and different groups: #; P<0.05, ###; P<0.001

Figure 2

Testicular expression of miR-34a (a) and protein levels of Silent information regulator 1 (SIRT1) (b) and Ac-p53 (c) and their immunoblotting in control (C), voluntary exercise (VE), diabetic (D), and voluntary exercise diabetic (VED) groups. Data are presented as Mean±SEM (n= 8). Comparisons were done by one-way ANOVA followed by Tukey’s post hoc test. Statistical differences between control and different groups: *; P<0.05, **; P<0.01, ***; P<0.001, statistical differences between diabetic and different groups: ##; P<0.01, ###; P<0.001

Figure 3

Photomicrographs of TUNEL test in the testicles of control (C), voluntary exercise (VE), diabetic (D), and voluntary exercise diabetic (VED) groups. The TUNEL-positive cells (apoptotic) display dark nuclei and TUNEL-negative cells (normal) display blue nuclei. (TUNEL immunohistochemistry staining, ×400)

Figure 4

(A) cellular apoptosis index (%) and (B) tubular apoptosis index (%) in control (C), voluntary exercise (VE), diabetic (D) and voluntary exercise diabetic (VED) groups. Data are presented as Mean±SEM (n= 8). Comparisons were done by one-way ANOVA followed by Tukey’s post hoc test. Statistical differences between control and different groups: ***; P<0.001, statistical differences between diabetic and different groups: ###; P<0.001