Gynura procumbens Improved Fertility of Diabetic Rats: Preliminary Study of Sperm Proteomic

Abstract

Gynura procumbens (GP) is a medicinal herb that has long been known as anti-inflammatory and antihyperglycaemic. Recently, this herbal extract has been associated with a profertility effect, suggesting its applicability in treating both diabetes and male infertility. In this study, the effects of GP aqueous extract (GPAE) on diabetic rats were investigated through evaluating testes histology and androgen hormone levels as well as the implantation sites of female rats on copulation with the treated male rats. Three dosages of GPAE were used (150, 300, and 450 mg/kg), and there were three control groups [normal, diabetic, and metformin-treated diabetic]. Testes histology, androgen hormone levels, and number of implantation sites of the GPAE-treated groups matched those of the normal group in contrast to the diabetic and metformin-treated diabetic controls. Sperm proteomics analysis identified 666 proteins, but only 88 were consistently found in all the control and 450-mg/kg GPAE-treated groups. Four proteins, including cysteine-rich secretory protein 1, carboxylesterase 5A, zona pellucida binding protein, and phosphatidylethanolamine-binding protein 1, were significantly upregulated with GPAE treatment compared with the diabetic control, matching the protein levels of the normal group. These proteins were mainly involved in sperm maturation, sperm capacitation, and sperm-egg interaction, suggesting that GP treatment was able to restore the fertility of male diabetic rats at molecular protein level. In conclusion, GP treatment effectively treats infertility of male diabetic rats, possibly through the upregulation of proteins related to sperm maturation and sperm-egg interaction.

Figure 1

Cross-section of testes for each group at magnification 400×. (a) Normal (nontreated) control, (b) diabetic control (nontreated diabetic), (c) metformin-treated diabetic as well as Gynura procumbens aqueous extract (GPAE) treatment; (d) 150 mg/kg, (e) 300 mg/kg, and (f) 450 mg/kg on diabetic rats.

Figure 2

Representative figures of the number of implantation sites after mated with male rats from the (a) diabetic group (nontreated) and (b) Gynura procumbens aqueous extract (GPAE) treated group (450 mg/kg).

Figure 3

Classification of 88 sperm proteins by gene ontology: cellular component, molecular function, and biological process.

Figure 4

Four significantly expressed proteins in Gynura procumbens aqueous extract (GPAE) treatment compared to the diabetic nontreated group. These proteins including carboxylesterase (CES5A) (a), cysteine-rich secretory protein 1 (CRISP1) (b), phosphatidylethanolamine-binding protein1 (PEBP1) (c), and zona pellucida binding protein (ZPBP) (d) are related to sperm development and sperm-egg interaction.