Increased expression of hypoxia-inducible factor-1α and connective tissue growth factor accompanied by fibrosis in the rat testis of varicocele

Abstract

ObjectiveWe investigated hypoxia inducible factor-1α (HIF-1α), connective tissue growth factor (CTGF) expression and fibrosis in the testis of rats with surgically induced varicocele. Materials and methodsA total of 47 adult male Sprague-Dawley rats were arranged in 3 groups, namely group 1 (varicocele operation 4 weeks ago, n=10; sham operation 4 weeks ago, n=5), group 2 (8 weeks, n=11; n=5), and group 3 (12 weeks, n=11; n=5). The rats in every group underwent bilateral orchiectomy 4, 8, and 12 weeks after the operations, respectively. HIF-1α and CTGF expression of both testes in group 3 were studied by real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Fibrotic change was assessed by quantitative image analysis. ResultsHIF-1α mRNA expression in testes tissues in varicocele operation and sham controls showed no significant differences in RT-PCR. However, CTGF mRNA expressions in left testes were found to be significantly different between varicocele operation and sham controls. HIF-1α staining was present in both testes of all specimens and CTGF staining was present in 10 left and 8 right testes of 11 specimens. However HIF-1α and CTGF staining were absent in control group. There were significant fibrotic changes of both testes in groups 2 and 3. There were significant differences in fibrotic change along the durations of surgical varicocele. ConclusionsThis study reveals that experimental varicocele in the rat is associated with HIF-1α and CTGF expression and it is accompanied by fibrotic change in the testis.