| Objective: The shortage of thyroid hormone will damage the target organs and tissues. That hypothyroidism leads to the change of structure and function in kidney has been proved by a lot of clinical work and experiments on animals. To study the pathogenesis of renal damage, this study was designed: To construct animal model of hypothyroid rats at various levels, and to determine the thyroid function of the rats; To investigate the expression of c-Jun and TGF-β1 in kidney of hypothyroid rats with the method of immunohistochemistry and analyse the change of protein content; To observe the gene expression of c-Jun in kidney tissue. To study the relationship between different levels of hypothyroidism and AP-1, TGF-β1 in rats, discuss the effect of AP-1 on kidney damage in hypothyroid state. More methods will be supplied to clinical works.Methods: Wistar rats were divided into gentle hypothyroid group, dense hypothyroid group, and control group at random. 12 weeks later, serum levels of thyroid hormone were determined. The expression of c-Jun and TGF-β1 in kidney was observed by immunohistochemistry and RT-PCR. This study included the following five parts:1 Experimental rats groups and reproduced hypothyroid models: Thirty Wistar rats were divided into gentle hypothyroid group(GHG), density hypthyroid group(DHG), and control group(CL) at three levels randomly. Every rat was weighted 70-100 gram and at the age of 4-5weeks. Half of the rats were male and half were female. There were 10 rats in each group. All rats were fed with low-iodine diet(the concentration of iodine is 50μg/kg) derived from an endemic goiter area. DHG, GHG, and CL Wistar rats drank deionized water containing potassium iodide of 0.00μg/L, 163.8μg/L, and 381.7μg/L. They were killed after being bred for 12 weeks. Each rat took was evaluated in 20gram feed and 30ml water every day.2 The serology determining: To take 4ml no-anticoagulant whole blood from each rat, then centrifuge the blood and obtain 2 ml serum or so. The thyroid function was determined by serum levels of TT3, TT4, FT3, FT4.3 The morphology transform of kidney in hypothyroid rats: The morphology observation was performed by using HE dyeing method, and observed under optical microscope.4 The analysis of immunohistochemistry: The protein expression of c-Jun and TGF-β1 were compared among the three groups by immunohistochemistry method.5 The gene expression of c-Jun in kidney of rats: Total RNA from fresh kidney tissue using Trizol one-step-method were reversed transcribed to be cDNA. cDNA and differert prime were mixed in PCR to amplificate target gene(c-Jun) and internal controlβ-actin gene. The product were fractionated on 1.2% agarose gels. The ratio of the intension of target gene to internal control were calculated.Results:1 Compared with CL, The TT3, TT4, FT3, FT4 of DHG were significantly decreased(P<0.01), the TT4, FT4 of GHG were significantly decreased(P<0.01), the TT3, FT3 of GHG were not significantly decreased(P>0.05). Compared with GHG, The TT3, TT4, FT3, FT4 of DHG were significantly decreased(P<0.01).2 Compared with CL, the basal membrane of glomerulus and renal tubules in GHG group was thicker, the mesentery region of glomeruli became larger and the matrix was increased, the area of glomeruli was decreased. The change of DHG group was more evident than the GHG group.3 There was a little expression of c-Jun and TGF-β1 protein in control group. Compared with CL, the c-Jun of DHG was significantly increased(P<0.01), the c-Jun of GHG was not significantly increased (P>0.05). Compare with GHG, The c-Jun of DLIG was significantly increased(P<0.05).Compared with CL, the TGF-β1 of DHG was significantly increased(P<0.01), the TGF-β1 of GHG was significantly increased (P <0.05). Compare with GHG, The TGF-β1 of DHG was significantly increased(P<0.05).4 Compared with CL, the c-Jun mRNA of DHG was significantly increased(P<0.01), the c-Jun mRNA of GHG was not significantly increased (P>0.05). Compare with GHG, the c-Jun mRNA of DHG was significantly increased(P<0.01).Conclusions:1 Wistar rats are suitable animals to produce hypothyroid animal models because hypothyroidism have been produced successfully by fed with low-iodine diet.2 Hypothyroidism caused that the basal membrane of glomerulus and renal tubules grew thicker, the mesentery region of glomeruli became larger and the matrix was increased, the area of glomeruli was decreased. The damage became more evident as hypothyroidism worsened.3 Notable upregradulation of c-Jun protein coincided with an apparent increase of TGF-β1 expression in kidney of hypothyroid rats. These alterations were enhanced significantly along with the degree of thyroid hormone deficiency.The expression of c-Jun in glomeruli was larger than renal tubules in three groups. The expression of TGF-β1 in glomeruli was similar to renal tubules in CL, GHG groups. The expression of TGF-β1 in glomeruli was larger than renal tubules in DHG group. That the kidney damage indicated in hypothyroid state was mainly in glomeruli.4 The expression of c-Jun mRNA was enhanced significantly along with the degree of hypothyroidism.5 Hypothyroidism might lead to kidney damage by activating AP-1, which can cause the activation of some cytokines and renal cells.
|
PDF Full Text Request