Glutathione (GSH) improves sperm quality and testicular morphology in streptozotocin-induced diabetic mice

Abstract

Diabetes mellitus (DM) is known to cause reproductive impairment. In men, it has been linked to altered sperm quality and testicular damage. Oxidative stress (OS) plays a pivotal role in the development of DM complications. Glutathione (GSH) is a part of a nonenzymatic antioxidant defense system that protects lipid, protein, and nucleic acids from oxidative damage. However, the protective effects of exogenous GSH on the male reproductive system have not been comprehensively examined. This study determined the impact of GSH supplementation in ameliorating the adverse effect of type 1 DM on sperm quality and the seminiferous tubules of diabetic C57BL/6NTac mice. GSH at the doses of 15 mg kg^-1 and 30 mg kg^-1 was given intraperitoneally to mice weekly for 6 consecutive weeks. The mice were then weighed, euthanized, and had their reproductive organs excised. The diabetic (D Group) showed significant impairment of sperm quality and testicular histology compared with the nondiabetic (ND Group). Diameters of the seminiferous lumen in diabetic mice treated with 15 mg kg^-1 GSH (DGSH15) were decreased compared with the D Group. Sperm motility was also significantly increased in the DGSH15 Group. Improvement in testicular morphology might be an early indication of the protective roles played by the exogenous GSH in protecting sperm quality from effects of untreated type 1 DM or diabetic complications. Further investigation using different doses and different routes of GSH is necessary to confirm this suggestion.

Keywords: diabetes mellitus; glutathione; mice; sperm quality; testis histology.

Figure 1

Effect of GSH on (a) body weight and (b) blood glucose level in diabetic mice after 50 days of treatment (n = 6). Values are presented as mean ± s.d. ^*P < 0.05, the indicated group compared to day 0. ND: nondiabetic control group; D: diabetic control group; DGSH15: diabetic mice treated with GSH at 15 mg kg⁻¹ BW; DGSH30: diabetic mice treated with GSH at 30 mg kg⁻¹ BW; GSH: glutathione; s.d.: standard deviation; BW: body weight.

Figure 2

Effect of GSH on sperm parameters after 50 days of treatment (n = 6) on (a) sperm number, (b) sperm motility, and (c) abnormal sperm morphology. Data are represented as mean ± s.d. ^*P < 0.05, the indicated group compared to ND Group, ^#P < 0.05, the indicated group compared to D Group. ND: nondiabetic control group; D: diabetic control group; DGSH15: diabetic mice treated with GSH at 15 mg kg⁻¹ BW; DGSH30: diabetic mice treated with GSH at 30 mg kg⁻¹ BW; s.d.: standard deviation; ANOVA: analysis of variance; GSH: glutathione; BW: body weight.

Figure 3

Smears of sperms were stained with Eosin Y (×1000). (a) Normal. (b) Amorphous. (c) Bent head. (d) Headless. (e) Defective head. (f) Folded. (g) Short tail. (h) Coiled tail.

Figure 4

Effect of exogenous GSH on mice testes after 50 days of treatment (n = 6). Embedded testis tissue blocks were cut into 5-μm sections and stained with H and E. Black lines indicate diameter of seminiferous tubule, red lines indicate diameter of seminiferous lumen, and yellow lines indicate epithelial height of seminiferous tubule. Representative images of testicular morphology at different magnifications. Scale bars in the left column (a, c, e and g) represent 1000 μm, while scale bars in the right column (b, d, f and h) represent 200 μm. ST: seminiferous tubule; SL: seminiferous lumen; EH: epithelial height; ND: nondiabetic control group; D: diabetic control group; DGSH15: diabetic mice treated with GSH at 15 mg kg⁻¹ BW; DGSH30: diabetic mice treated with GSH at 30 mg kg⁻¹ BW; GSH: glutathione; H and E: hematoxylin and eosin; BW: body weight.

Figure 5

Effect of exogenous GSH on changes in the testicular morphology of seminiferous tubules in diabetic mice after 50 days of treatment (n = 6). (a) Diameter of seminiferous tubules, (b) diameter of seminiferous lumen, and (c) epithelial height. All measurements were done under the same magnification. Data are represented as mean ± s.d. ^*P < 0.05, the indicated group compared to ND Group, ^#P<0.05, the indicated group compared to D Group. ND: nondiabetic control group; D: diabetic control group; DGSH15: diabetic mice treated with GSH at 15 mg kg⁻¹ BW; DGSH30: diabetic mice treated with GSH at 30 mg kg⁻¹ BW. GSH: glutathione; s.d.: standard deviation; ANOVA: analysis of variance; BW: body weight.