Effects Of Tannic Acid On Adiponectin And Gonads Of Male Brandt’s Voles

Brandt’s vole(Lasiopodomys brandtii)is one kinds of small herbivorous mammal inhabits in Inner Mongolia grassland.The plants it feed on contain plant secondary metabolite,tannins,and the content of tannins fluctuates with season.Tannic acid(TA)is the simplest tannins.It was found that TA could affect the autophagy in testicular of Brandt’s voles and influence its reproduction,and TA also could change the lipid levels in Brandt’s voles.Adiponectin,an adipokine secreted by adipose tissue,had co-relation with body fat mass and could regulate the inflammation,autophagy and metabolism in the thesis of animals.So,it should be interesting to investigate whether the content of adiponectin could be changed with the change of lipids induced by TA,which in turn,could influence the function of testicular tissue in Brandt’s voles.Therefore,in this study,90-day-old male Brandt’s voles were randomly divided into three groups,they were control(distilled water),600 mg·kg-1 TA and 1200 mg·kg-1 TA group,respectively.And they were given TA by intragastric administration continuously for 18 days.The voles were weighed before and after TA treatment,and the change rate of their weight calculated.Serum adiponectin content,tumour necrosis factor(TNF-α),and interleukin-6(IL-6)levels were detected by Enzyme-linked immunosorbent assay(ELISA),RT-qPCR(Real-time quantitative PCR)was used to detect the mRNA expression level of adiponectin polymerization-related genes DsbA-L(Disulfide-bond A oxidoreductase-like protein)and Erol-Lα(Endoplasmic oxidoreductin-l-like protein alpha),as well as ERp44(Endoplasmic reticulum resident protein 44)in epididymal adipose tissue of male Brandt’s vole.Western blot(WB)was used to detect the expression levels of adiponectin signalling pathway-related proteins,glucose transport protein and lactate transport protein in the gonads of male Brandt’s voles.In order to observe the morphology of testicular tissue,its frozen sections were dyed by hematoxylin-eosin staining.The enzyme activity of Superoxide dismutase(SOD),Catalase(CAT)and Lactate dehydrogenase(LDH)was assayed with test kits.The contents of malondialdehyde(MDA),pyruvate and lactate were detected with chromogenic method.So,the effect of TA on the adiponectin and its receptors could be observed,as well as the proteins related to its polymerization and signaling pathway.And the effect of TA on the inflammation status,antioxidation and the metabolite of glucose,all of them related to the adiponectin also would be measured.Finally,the role of adiponectin in the influence of TA on the thesis of Brandt’s voles would be explored,which would be benefit to elucidate the mechanism of the influence of TA on the reproduction of Brandt’s voles.The main results were as follows.1.TA significantly reduced the weight of male Brandt’s vole and had dose-dependently.2.After treatment with 600 mg·kg-1 TA,the serum adiponectin content increased significantly compared with the control group.RT-qPCR results showed that DsbA-L and Erol-La transcription levels increased significantly only in 600 mg·kg-1 tannic acid group.1200 mg·kg-1 TA made voles expressed more ERp44 than 600 mg·kg-1 TA.These results showed that 600 mg·kg-1 TA increased the serum adiponectin content of male Brandt’s vole,which may be induced by the transcription of the adiponectin polymerization gene in adipose tissue.And the increase of ERp44 made by 1200 mg·kg-1 TA might keep adiponectin in cells.3.The results of western blot showed that the expression of AdipoR1 and AMPK in the testis of 600 mg·kg-1 TA group increased significantly,but there was no difference in the expression of AdipoR2 and PPARa among three groups.And 600 mg·kg-1 TA also increased the expression of GLUT1 and MCT4,meanwhile,1200 mg·kg-1 TA only increased the expression of MCT4.Both of the testicular content of pyruvate and lactic acid increased after voles treated with 600 mg·kg-1 TA,but 1200 mg·kg-1 TA only increased lactic acid content.The results meant that 600 mg·kg-1 TA could activate the adiponectin signal pathway in the testis and increase glucose uptake and lactate transport to germ cells in the testis,which was beneficial to spermatogenesis.4.Treatment with different doses of TA had no significant effect on the gonad index.Compared with the control group,only the epididymal index in 1200 mg·kg-1 TA group decreased significantly.The epididymal fat index of Brandt’s vole treated with 600 mg·kg-1 TA was significantly lower than that of the control group。After the testis was dyed with HE dyeing,it could be detected that 600 mg·kg-1 TA significantly enlarged the inner diameter of seminiferous tubules.In contrast,1200 mg·kg-1 TA did not change the inner diameter of seminiferous tubules.5.The antioxidant capacity of Brandt’s vole testis is greatly enhanced after TA treatment.Compared with the control group,the treatment of 600 mg·kg-1 TA increased the CAT activity of male Brandt’s vole testis and 1200 mg·kg-1 TA reduced the MDA content.TA treatment also regulates the secretion of inflammatory factors in testis of male Brandt’s vole.Compared with the control group,the treatment of 600 mg·kg-1 TA decreased the TNF-α in the testis of male Brandt’s vole,1200 mg·kg-1 TA reduced the content of IL-6 in testis.It indicated that TA could alleviate testicular inflammation of Brandt’s vole.So,all of these results suggested that TA influence adiponectin and its signal pathway in testis of adult male Brandt’s vole dose-dependently.600 mg·kg-1 TA could increase the serum adiponectin content of Brandt’s vole,which in turn,activate AMPK signaling pathway in testis.Then,the uptake of glucose in testis and the transport of lactic acid to germ cells were promoted by the increase of the expression of GLUT1 and MCT4 proteins,which providing energy support for germ cell development.Meanwhile,the alleviation of inflammation and improvement of antioxidatation also provides a stable environment for spermatogenesis.So,the inner diameter of seminiferous tubule was increased.1200 mg·kg-1 TA treatment also improved the antioxidant level and inflammatory status in testis,but it did not activate the adiponectin signaling pathway in testis.