Methylglyoxal, a reactive dicarbonyl compound, is mainly formed from glycolysis. Methylglyoxal can lead to the dysfunction of mitochondria, the depletion of cellular anti-oxidation enzymes and the formation of advanced glycation ends. Previous studies showed that the accumulation of methylglyoxal and advanced glycation ends can impair the oocyte maturation and reduce the oocyte quality in aged and diabetic females. In this study, we showed that resveratrol, a kind of phytoalexin found in the skin of grapes, red wine and other botanical extracts, can alleviate the adverse effects caused by methylglyoxal, such as inhibition of oocyte maturation and disruption of spindle assembly. Besides, methylglyoxal-treated oocytes displayed more DNA double strands breaks and this can also be decreased by treatment of resveratrol. Further investigation of these processes revealed that methylglyoxal may affect the oocyte quality by resulting in excessive reactive oxygen species production, aberrant mitochondrial distribution and high level lipid peroxidation, and resveratrol can block these cytotoxic changes. Collectively, our results showed that resveratrol can protect the oocytes from methylglyoxal-induced cytotoxicity and this was mainly through the correction of the abnormity of cellular reactive oxygen species metabolism.
Methoxychlor (MXC) is used worldwide against insects and other pests. This organochlorine pesticide acts as a xenoestrogen, promotes oxidative stress, and is considered cytotoxic and genotoxic, causing abortions and stillbirths in females. Mechanistically related estrogens and oxidants affect oocyte meiosis, so we investigated the effects of MXC on mouse oocyte meiotic maturation. Our results showed that maturation rates of MXC-treated oocytes were lower than those of controls, which was due to abnormal spindle morphologies and DNA double-strand breaks, as confirmed by increased γ-H2AX foci. Our findings also suggest that MXC may affect oocyte quality by causing the accumulation of superoxide radicals and other reactive oxygen species, aberrant mitochondrial distribution, decreased mitochondrial membrane potential, and increased lipid peroxidation. Thus, exposure to MXC negatively affects oocyte meiotic maturation, primarily through impairments in cellular ROS metabolism. Mol. Reprod. Dev. 83: 768-779, 2016 © 2016 Wiley Periodicals, Inc.
KIF2A, a member of the kinesin-13 family, has been reported to play a role in spindle assembly in mitosis. However, its function in mammalian meiosis remains unknown. In this research, we examined the expression, localization and function of KIF2A during mouse oocyte meiosis. KIF2A was expressed in some key stages in mouse oocyte meiosis. Immunofluorescent staining showed that KIF2A distributed in the germinal vesicle at the germinal vesicle stage and as the spindle assembling after meiosis resumption, KIF2A gradually accumulated to the entire spindle. The treatment of oocytes with taxol and nocodazole demonstrated that KIF2A was co-localized with α-tubulin. Depletion of KIF2A by specific short interfering (si) RNA injection resulted in abnormal spindle assembly, failure of spindle migration, misaligned chromosomes and asymmetric cell division. Meanwhile, SKA1 expression level was decreased and the TACC3 localization was disrupted. Moreover, depletion of KIF2A disrupted the actin cap formation, arrested oocytes at metaphase I with spindle assembly checkpoint protein BubR1 activated and finally reduced the rate of the first polar body extrusion. Our data indicate that KIF2A regulates the spindle assembly, asymmetric cytokinesis and the metaphase I-anaphase I transition in mouse oocyte.
Background: Idiopathic membranous nephropathy (IMN) is the most common cause of nephrotic syndrome in adults. Although various studies have demonstrated the efficacy of tacrolimus combined with corticosteroids for treating IMN, both tacrolimus and corticosteroids have been shown to be diabetogenic, particularly following organ transplantation. Furthermore, the frequency and risk factors for new-onset diabetes mellitus (NODM) in IMN patients treated with tacrolimus plus low-dose corticosteroids remain unclear. Objectives: To evaluate the incidence of NODM in IMN patients undergoing tacrolimus plus low-dose corticosteroid therapy and to confirm the risk factors for NODM development. Methods: This retrospective study recruited 72 eligible patients with biopsy-proven IMN from our center, between September 2013 and June 2018. All subjects were treated with tacrolimus plus low-dose corticosteroids for a minimum of 3 months. The primary outcome was NODM development during the follow-up period. The secondary outcome was complete or partial remission. Patients were divided into 2 groups: patients with NODM (NODM group) and those without NODM (No-NODM group). Demographic and clinical data at baseline and follow-up were assessed. Results: During follow-up, 31 of the 72 patients developed NODM (43.0%). The median time to occurrence was 3 months after treatment initiation. NODM patients were significantly older (median age 59 vs. 40 years) than No-NODM patients. Baseline fasting blood glucose levels were slightly higher in the NODM group; however, the difference was not significant (p = 0.07). Older age was an independent risk factor for NODM (OR 1.73 and 95% CI 1.20–2.47, p = 0.003). Overall kidney remission rates were 80.6%. There was no significant difference in remission rate between groups. There was a significant difference in development of pulmonary infection, which occurred in 7 NODM patients and only in 1 No-NODM patient (p = 0.018). IMN reoccurred in 5 NODM patients but only 1 No-NODM patient. Conclusions: Tacrolimus plus low-dose corticosteroid therapy was an efficient treatment for IMN; however, it was accompanied by increased NODM morbidity, which should be considered serious, due to the increased risk of life-threatening complications. Increasing age was a major risk factor for NODM in IMN patients treated with tacrolimus plus low-dose corticosteroid therapy.
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