There are also data showing potential

There are also data showing potential beneficial effects of SGLT2i on non-alcoholic fatty liver disease (NAFLD) [[14], [15], [16], [17]], a hepatic manifestation of the metabolic syndrome that has been linked to type 2 diabetes mellitus (T2DM) development and increased cardiovascular (CV) as well as liver morbidity and mortality [[18], [19], [20], [21]]. Furthermore, SGLT2i have been reported to decrease epicardial fat [[22], [23], [24], [25], [26]]. It should be noted that increased epicardial adiposity has been related to coronary artery disease, cardiac arrhythmias, CV risk factors, T2DM, NAFLD and chronic kidney disease [[27], [28], [29], [30], [31]]. In this context, excessive peri-organ or intra-organ adipose tissue, including epicardial, perivascular, peripancreatic, perirenal and intramuscular fat has been suggested as an underestimated CV risk factor [32].
Declaration of interest
Introduction For most mammalian cells, glucose is an important metabolic substrate and also the basic fuel molecule, including germ Licofelone (Gómez et al., 2006; Kim and Moley, 2007). Glucose play an important role in normal reproductive functions (Gómez et al., 2006). Glucose is transported into the cell via the facilitative glucose transporter (GLUT) proteins (Kim and Moley, 2007). Currently, the GLUT family has 14 members (Scheepers et al., 2004, Uldry and Thorens, 2004, Wood and Trayhurn, 2003, Zhao and Keating, 2007). According to sequence similarities, the GLUT family is divided into three classes, namely class I (GLUT 1–4 and GLUT14), class II (GLUT 5, 7, 9 and 11) and class III (GLUT 6, 8, 10, 12 and H+/myo-inositol transporter (HMIT)) (Joost and Thorens, 2001). Among them, glucose transporter 8 (GLUT8) appears to be the major transporter for transporting glucose in testis (Doege et al., 2000, Ibberson et al., 2000, Kim and Moley, 2007). The expression level of GLUT8 is higher in testes than other tissues in the testes of human (Schürmann et al., 2002), mouse (Gómez et al., 2006, Kim and Moley, 2007) and rat (Ibberson et al., 2002). Whereas, cellular localization of GLUT8 protein in testis of different mammalian species remains controversial. It has been reported that GLUT8 was expressed in spermatids in mouse (Gómez et al., 2006, Schürmann et al., 2002) and human testes (Schürmann et al., 2002). A report has showed that localization of GLUT8 was more intensive in the round spermatids than in other germ cells of mouse testis (Kim and Moley, 2007). In the rat testes, GLUT8 protein was expressed in type I spermatocytes (Ibberson et al., 2002) and spermatids (Gómez et al., 2009). In spermatozoa fuel supply, GLUT8 paly a pivotal role (Gómez et al., 2006, Schürmann et al., 2002). The normal sperm function and spermatogenesis were affected by glucose uptake via GLUT8 in the mouse (Kim and Moley, 2007). On the basis of these data, we suggested that GLUT8 is associated with germ cells development and spermatogenesis. To our knowledge, the GLUT8 expression level and pattern were yet unknown in the boar testis. Pigs are not only the major source of meat for humans, but also an indispensable model for biological research. The pig is a common farm animal in China. The study of pig reproduction is of important significance to pig breeding. Therefore, the present study was designed to determine the expression of GLUT8 mRNA and protein in boar testis. In addition, the cellular localization of GLUT8 was examined in seminiferous tubules by immunohistochemistry. Whether the expression of GLUT8 play an important role in boar spermatogenesis was evaluated. The data provide a histological basis for glucose uptake via GLUT8 in spermatogenesis in boar testes.
Materials and methods
Results
Discussion In the present study, the expression and localization of GLUT8 were investigated by using RT-PCR, Western Blotting and immunohistochemistry in the adult boar testes. The results of RT-PCR and Western Blotting analysis showed that the GLUT8 mRNA and protein were expressed in the adult boar testes. Western Blotting analysis showed the antibody specificity for boar testes protein. Immunohistochemistry results showed that the expression of GLUT8 mainly in the spermatocytes, elongated and round spermatids in the adult boar seminiferous tubules. The GLUT8 stage specific expression was observed in the seminiferous tubules (Fig. 1, Fig. 2). And the GLUT8 expression persists during eight stages of boar spermatogenesis.