Objective This study aims to define the effects of hypothyroidism on c-fos and c-jun mRNA expression in rat testes to provide a theoretical basis for prevention and control of iodine deficiency disorders (IDD). Methods According to body weight (200 - 240 g), 20 Wistar male rats were divided into control group and hypothyroidism group (1 ml/100 g, 0.1% propylthiouracil by intragastric administration) by digital table. There were 10 male rats in each group and body weight was observed every 3 days. After 60 days, all rats were killed. The levels of thyroid hormones [total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH)] were measured by radioimmunoassay. The mRNA expression levels of c-fos and c-jun in testes were detected by real-time quantitative PCR. Results Compared with control groups [(298.20 ± 12.15), (344.00 ± 13.73) g], the weights of hypothyroidism groups in 30 days [(239.00 ± 15.02) g] and in 60 days [(232.67 ± 17.86) g] were significant decreased (t=7.704, 11.380, all P<0.05). The levels of TT3 [(373.32 ± 101.31) ng/L] and TT4 [(4.00 ± 0.89) × 103 ng/L] in serum of hypothyroidism group were found to be significantly decreased, whereas the level of TSH [(5.77 ± 0.89) × 103 U/L] was increased in comparison with those of the control groups [(1 000.01 ± 273.53) ng/L, (44.33 ±7.84) × 103 ng/L, (1.87 ± 0.70) × 103 U/L, t = 5.262, 12.520, 8.413, all P< 0.05]. Compared with control group (1.00 ± 0.08, 1.01 ± 0.04), the c-fos and c-jun mRNA expression (0.67 ± 0.03, 0.75 ± 0.02) of hypothyroidism group was significant decreased (t = 12.382, 13.784, all P < 0.05). Conclusion Hypothyroidism may reduce mRNA expression levels of testicular c-fos and c-jun, and then damage the reproductive system in male rats.

Objective To define the effect of hypothyroidism on oxidative stress,p38 and c-Jun N-terminal kinases (JNK) mRNA expression in testicular mitochondria of male rats,and to explore the mechanism of hypothyroidism on reproduction.Methods According to body weight (240-270 g),30 male Wistar rats were divided into control group (C group,1 ml/kg normal saline by intragastric administration),low-dose group (L group,0.1 mg/kg propylthiouracil 1 ml/kg by intragastric administration) and high-dose group (H group,10.0 mg/kg propylthiouracil 1 ml/kg by intragastric administration),10 rats in each group,body mass was weighed once every 3 days.After 60 days,all rats were killed.The levels of thyroid hormones [total triiodothyronine (TT3),total thyroxine (TT4),and thyroid stimulating hormone (TSH)] were measured by radioimmunoassay.The activities of superoxide dismutase (SOD) and catalase (CAT) in the testicular mitochondria were determined with spectrophotometric assay.The mRNA expression levels of p38 and JNK in testicular mitochondria were detected by real-time quantitative PCR.Results The weights of H group in 30 and 60 days [(265.73 ± 5.10),(253.72 ± 5.09) g] were significantly decreased in comparison with those of C group [(344.62 ± 4.69),(395.33 ± 8.36) g] and L group [(333.66 ± 3.53),(386.08 ± 7.70) g,P ＜0.05].While,testis organ coefficient of H group [(1.20 ± 0.05) g/100 g] were significantly increased compared with those of L group [(0.93 ± 0.03) g/100 g] and C group [(0.88 ± 0.03) g/100 g,P ＜ 0.05].The serum levels of TT3 [(0.39 ± 0.01) nmol/L] and TT4 [(15.47 ± 1.21) nmol/L] in H group were found to be significantly decreased compared with those of C group [(0.86 ± 0.07),(45.56 ± 1.52) nmol/L] and L group [(0.79 ± 0.06),(39.02 ± 1.33) nmol/L,P ＜ 0.05];whereas the level of TSH [(0.65 ± 0.09) mU/L)] was increased in comparison with those of the C group [(0.18 ± 0.06) mU/L] and L group [(0.27 ± 0.05) mU/L,P ＜ 0.05].In addition,the level of SOD in H group [(60.37 ± 3.14) U/mg prot] was decreased compared with that of C group [(75.18 ± 6.13) U/mg prot,P ＜ 0.05];the level of CAT in H group [(1.46 ± 0.25) U/mg prot] and L group [(1.67 ± 0.39) U/mg prot] decreased significantly compared with that of C group [(3.79 ± 0.44) U/mg prot,P ＜ 0.05].And compared with C (1.000 0 ± 0.000 0) and L (1.114 2 ± 0.124 1) groups,p38 mRNA expression in H group (1.387 4 ± 0.122 0) was significantly increased (P ＜ 0.05).However,there was no significant change in JNK mRNA expression between groups (F =0.95,P ＞ 0.05).Conclusion Hypothyroidism may induce oxidative stress of testicular mitochondria leading to the change of p38 cell signal path and then damage the reproductive system in male rats.