Chronic scrotal heat stress causes testicular interstitial inflammation and fibrosis: An experimental study in mice

• Published in: International journal of reproductive biomedicine (Yazd, Iran) Iran), 2022-07, Vol.20 (7), p.569-580
• Main Authors: Nguyen-Thanh, Tung, Dang-Van, Phuoc, Dang-Ngoc, Phuc, Kim, Won, Le-Minh, Tam, Nguyen-Vu, Quoc-Huy
• Format: Article
• Language: English
• Subjects: Fibroblasts; heat stress, testicular, inflammation, fibrosis; Inflammation; Rodents; Spermatogenesis; Testes
• ISSN: 2476-4108; 2476-3772
• DOI: 10.18502/ijrm.v20i7.11559

Background: Chronic heat stress is a risk factor that adversely affects the reproduction system. Inflammation and fibrosis are 2 important response processes to damaged tissues. Objective: This study investigates the association of chronic scrotal heat stress with testicular interstitial inflammation and fibrosis in mice. Materials and Methods: For all experiments, 8-10 wk old male Swiss mice (Mus musculus) (20-23 gr) were divided into 3 groups (n = 10/each). The heat-stress groups were submerged in a water bath at 37°C and 40°C, while the control group was treated at 25°C. The testicular tissues underwent hematoxylin and eosin staining, picro sirius red staining, and immunohistochemistry for intercellular adhesion molecule-1, fibroblast-specific protein 1, F4/80, collagen I, and Ki-67 staining to determine the testicular interstitial inflammation and fibrosis. Results: Chronic scrotal heat stress impairs spermatogenesis and reverses testicular histological structure. In this study, heat stress significantly induced increased interstitial cell proliferation and upregulation of intercellular adhesion molecule-1 expression in the interstitial testicular tissue. In the interstitial testicular tissue, the number of F4/80-positive macrophages and the number of fibroblast-specific protein 1- positive fibroblasts were significantly increased in the heat-exposed groups compared to those in the control group. The heat exposed groups had substantially increased extracellular matrix collagen accumulation in their testicular interstitial tissues. Conclusion: Heat stress adversely affects the testicular structure and spermatogenesis, causes inflammation, and leads to testicular interstitial fibrosis. Key words: Heat stress, Testicular, Inflammation, Fibrosis.