Icariin improves testicular dysfunction via enhancing proliferation and inhibiting mitochondria-dependent apoptosis pathway in high-fat diet and streptozotocin-induced diabetic rats

Abstract

Background Diabetes mellitus (DM), a chronic metabolic disease, severely impairs male reproductive function. However, the underpinning mechanisms are still incompletely defined, and there are no effective strategies or medicines for these reproductive lesions. Icariin (ICA), the main active component extracted from Herba epimedii, is a flavonoid traditionally used to treat testicular dysfunction. Whether ICA can improve male reproductive dysfunction caused by DM and its underlying mechanisms are still unclear. In this study, by employing metformin as a comparative group, we evaluated the protective effects of ICA on male reproductive damages caused by DM and explored the possible mechanisms. Methods Rats were fed with a high fat diet (HFD) and then intraperitoneally injected with streptozotocin (STZ) to induce diabetes. Diabetic rats were randomly divided into T2DM + saline group, T2DM + metformin group and T2DM + ICA group. Rats without the treatment of HFD and STZ were used as control group. The morphology of testicular tissues was examined by histological staining. The mRNA expression levels were determined by quantitative real-time PCR. Immunostaining detected the protein levels of proliferating cell nuclear antigen (PCNA), hypoxia-inducible factor 1-alpha (HIF-1α) and sirtuin 1 (SIRT1) in testicular tissues. TUNEL assay was performed to determine cell apoptosis in the testicular tissues. The protein expression levels of HIF-1α and SIRT1 in the testicular tissues were determined by western blot assay. Results ICA effectively improved male reproductive dysfunction of diabetic rats. ICA administration significantly decreased fasting blood glucose (FBG) and insulin resistance index (IRI). In addition, ICA increased testis weight, epididymis weight, sperm number, sperm motility and the cross-sectional area of seminiferous tubule. ICA recovered the number of spermatogonia, primary spermatocytes and Sertoli cells. Furthermore, ICA upregulated the expression of PCNA, activated SRIT1-HIF-1α signaling pathway, and inhibited intrinsic mitochondria dependent apoptosis pathway by upregulating the expression of Bcl-2 and downregulating the expression of Bax and caspase 3. Conclusion These results suggest that ICA could attenuate male reproductive dysfunction of diabetic rats possibly via increasing cell proliferation and decreasing cell apoptosis of testis. ICA potentially represents a novel therapeutic strategy against DM-induced testicular damages.

Tropisetron improved testicular inflammation in the streptozotocin‐induced diabetic rats: The role of toll‐like receptor 4 (TLR4) and mir146a

“…[44] In other studies, Proanthocyanidin, icariin, and cerium oxide nanoparticles improved testicular apoptosis induced by diabetes by decreasing caspase 3 and NF-κB. [45,46] On the other hand, tropisetron inhibited F I G U R E 6 Histochemical analysis of caspase3 protein expression in different groups. (Mean ± SEM, N = 7), *compared with the control group, $ compared with the DM group (one-way ANOVA followed by Tukey's post hoc test).…”

“…[ 44 ] In other studies, Proanthocyanidin, icariin, and cerium oxide nanoparticles improved testicular apoptosis induced by diabetes by decreasing caspase 3 and NF‐κB. [ 45,46 ] On the other hand, tropisetron inhibited NF‐κB, caspase 3, and TNF‐α and protected amyloid‐beta‐induced neurotoxicity. [ 27 ] Moreover, Aminzadeh reported the protective effect of tropisetron on PC12 cells against high glucose‐induced apoptosis by suppressing Bax and caspase‐3 expressions.…”

Quercetin Ameliorates Testicular Damage in Zucker Diabetic Fatty Rats through Its Antioxidant, Anti-Inflammatory and Anti-Apoptotic Properties

“…Correspondingly to caspase-3 overexpression recorded in this study, Nna et al [42] observed caspase-3 mRNA as well as protein up-regulation, which correlated with an abrupt loss of testicular cells in STZ-induced diabetic rats. Similarly, He et al [67] commented on a significant caspase-3 positive immunocytochemical signal located primarily in Sertoli cells, spermatogonia, and spermatocytes of rats presenting with a severe hyperglycemia caused by STZ and a high fat diet. According to Ojo and Olorunsogo [18], who observed an increased release of cytochrome-c in diabetic rats, testicular apoptosis is primarily regulated by the mitochondrial pathway which corroborates our data on the BAX and Bcl-2 proteins whose interactions on the mitochondrial membrane have a decisive role in the initiation of apoptotic cell death.…”

Deciphering the myth of icariin and synthetic derivatives in improving erectile function from a molecular biology perspective: a narrative review

“…Although testosterone supplementation therapy (TST) has been reported to be potentially effective for these conditions, TST has potential adverse effects (81). The effect of ICA and ICAII in increasing testosterone levels could be related to their ability to mitigate the effects of Leydig cell damage in a variety of testicular damaging environmental exposures (e.g., diabetes, toxic substances) (82,84,85). More importantly, ICA and ICAII directly increase the level of steroids (the raw material required for testosterone production) and the expression of several key enzymes in testosterone synthesis (86)(87)(88).…”