The role of HIF-1α-mediated autophagy in ionizing radiation-induced testicular injury.

Testis, as a key organ for maintaining male fertility, are extremely sensitive to ionizing radiation (IR). IR-induced testicular dysfunction and infertility are common adverse effects of radiation therapy in patients with pelvic cancer. To study the phenotype and mechanism of IR-induced testicular injury, the mice were irradiated with different radiation doses (0, 2 and 5 Gy) below the semi-lethal dose for one month. Our present results showed that testicular weight and the serum testosterone levels significantly decreased with the structural injury of the testis in an IR dose-dependent manner, indicating that IR caused not only the structural damage of the testis, but also the functional damage. Further analysis by TUNEL staining and Western blotting found that IR induced the apoptosis in a dose-dependent manner as indicated by increased expressions of cleaved caspase3, p53 and Bax on Day 15 after IR treatment. Combined with significantly increased oxidative stress, these results indicated that IR-induced testicular damage may be a long-term, progressively aggravated process, accompanied by apoptosis. Given the role of autophagy in apoptosis, the present study also detected and analyzed the localization and expressions of autophagy-related proteins LC-3I/II, beclin1, p62 and Atg12 in testicular cells, and found that LC-3II, beclin1 and Atg12 expressions significantly increased in the testicular cells of mice irradiated with 2 Gy and 5 Gy, while p62 expression significantly decreased with 5 Gy, implying autophagy was involved in the apoptosis of testicular cells induced by IR. Furthermore, the expressions of HIF-1α and BNIP3 were significantly enhanced in the testis cells of mice irradiated with 2 Gy and 5 Gy, suggesting the potential role of HIF-1α/BNIP3-mediated autophagy in the apoptosis of testicular cells induced by IR. Taken together, our findings demonstrated that HIF-1α/BNIP3-mediated autophagy not only plays a protective effect on the testicular cells of mice irradiated with 2 Gy, but also induces the apoptosis of the testicular cells of mice irradiated with 5 Gy, indicating the double effects on apoptosis, which will help us further understanding the molecular mechanisms of IR-induced testicular injury, and will facilitate us further studies on testicular radioprotection.

Programmed gene expression change in mouse skin after ultraviolet radiation damage.

Ultraviolet (UV) radiation is a major cause of skin damage and carcinogenesis. Here, we systematically analyse the acute gene expression change in skin in vivo after UV exposure, aiming to establish the common C57BL/6 mouse strain as a convenient model for future pathological research and drug discovery. The back fur of C57BL/6 mice was depilated, and a mixed UV light source was used to irradiate the skin. Full-thickness skin samples were collected at 0, 0.5, 2, 6, 12 and 24 h. Total RNAs were extracted and subjected to RNA sequencing analysis. We found that the gene expression change in mouse skin is highly similar to previous reports in human skin. These include down-regulation of differentiation-related genes and extracellular matrix genes, and up-regulation of cytokine/chemokine genes. An early wave of activator protein 1 (AP-1) expression is induced, whereas activation of the p53 pathway is not significant. The impact of the AP-1 transcription factors and the antioxidant tea polyphenols is discussed. The analysis of acute gene expression change in skin after UV irradiation provides a starting point to investigate how the skin responds to genotoxic stress.

Respiratory Tract Infection: A Risk Factor for the Onset and Relapse of Adult-Onset Minimal Change Disease in Southern China.

AIMS/INTRODUCTION: Steroid resistance and frequent relapse are problems in the treatment of minimal change disease (MCD). However, epidemiological factors that influence steroid-resistant and relapse of MCD are rarely reported. This study evaluated potential factors that influence the onset and relapse of MCD and the epidemiological features of southern Chinese patients with adult-onset MCD. PATIENTS AND METHODS: Patients with adult-onset MCD were included from the Affiliated Hospital of Guangdong Medical University, which is located in the southernmost part of China's mainland, between 2015 and 2016. Potential influencing factors were investigated. RESULTS: Eighty-seven patients with incipient MCD were enrolled, and 85 of these patients were followed up; 71.8% (61/85) were steroid-sensitive and 28.2% (24/85) were steroid-resistant. In terms of seasonal distribution, the highest rate of incipient cases was in spring (39.1%, 34/87), which also showed a high rate of relapse cases (29.7%, 22/74). Among patients who were followed up for more than half a year and whose proteinuria completely resolved (69.4%, 59/85), 52.5% (31/59) were without relapse and 47.5% (28/59) were with relapse. Patients without relapse were older than those with relapse (P<0.05). Before disease onset, 20.7% (18/87) of patients with incipient MCD were diagnosed with infection, including 94.5% (17/18) with respiratory tract infection. Fourteen patients in complete remission posttreatment developed an infection before relapse, including 85.7% (12/14) with respiratory tract infection. CONCLUSION: Steroid resistance and frequent relapse are current challenges for the treatment of adult-onset MCD in southern China, and respiratory tract infection may be a risk factor for onset and relapse. Additionally, younger patients with MCD tend to have more frequent relapse.