Effects of Tannic Acid on Antioxidant Activity and Ovarian Development in Adolescent and Adult Female Brandt's Voles

RNA-seq transcriptome analysis provides new insights into the negative effects of tannic acid on the intestinal function of Brandt's voles (Lasiopodomys brandtii)

Tannic acid (TA), a significant plant secondary metabolite, is contained in the daily food of Brandt's voles. Its adverse effect on gut function has been shown in earlier research, but the underlying molecular mechanisms remain uncertain. In this study, male Brandt's vole (13 weeks old) were divided into two groups and given 0 (control) or 1,200 (TA-treated) mg•kg-1 TA for 18 days. Then RNA sequencing was used to conduct a thorough transcriptome analysis on the duodenum, jejunum, and ileum of Brandt's voles. Results showed that TA significantly increased serum total cholesterol concentration (P < 0.05) and decreased the nutrient digestibility (P < 0.05) of Brandt's voles. Furthermore, there were 174 differentially expressed genes (DEGs) in the duodenum, 96 DEGs in the jejunum, and 88 DEGs in the ileum between the control and TA-treated groups. Enrichment analysis revealed that many genes associated with bile secretion, fat digestion and absorption, innate immune response, and tight junction such as ABCG2, ABCG8, PEAK1, and IFR2, etc. were altered after TA treatment, which were verified by quantitative real-time PCR. These findings suggested that TA can change the expression of intestinal genes, thereby, altering nutrition metabolism and immunological function, eventually hindering the growth of Brandt's voles. The results of this study provide a theoretical basis for explaining how TA affects the gut function of Brandt's voles at the molecular level.

Tannic Acid Induces Intestinal Dysfunction and Intestinal Microbial Dysregulation in Brandt's Voles (Lasiopodomys brandtii)

Brandt's vole (Lasiopodomys brandtii) is a small herbivorous mammal that feeds on plants rich in secondary metabolites (PSMs), including tannins. However, plant defense mechanisms against herbivory by Brandt's voles are not clearly established. This study aimed to investigate the effects of dietary tannic acid (TA) on the growth performance, intestinal morphology, digestive enzyme activities, cecal fermentation, intestinal barrier function, and gut microbiota in Brandt's voles. The results showed that TA significantly hindered body weight gain, reduced daily food intake, changed the intestinal morphology, reduced digestive enzyme activity, and increased the serum zonulin levels (p < 0.05). The number of intestinal goblet and mast cells and the levels of serum cytokines and immunoglobulins (IgA, IgG, TNF-α, IL-6, and duodenal SlgA) were all reduced by TA (p < 0.05). Moreover, TA altered β-diversity in the colonic microbial community (p < 0.05). In conclusion, the results indicate that TA could damage the intestinal function of Brandt's voles by altering their intestinal morphology, decreasing digestive ability and intestinal barrier function, and altering microbiota composition. Our study investigated the effects of natural PSMs on the intestinal function of wildlife and improved our general understanding of plant-herbivore interactions and the ecological role of PSMs.

Zinc Oxide Particles Can Cause Ovarian Toxicity by Oxidative Stress in Female Mice Model

Introduction

Zinc oxide nanoparticles (ZnO NPs) participate in all aspects of our lives, but with their wide application, more and more disadvantages are exposed. The goal of this study was to investigate the toxicity of ZnO NPs in female mice ovaries and explore its potential mechanism.

Methods

In this study, adult female mice were orally exposed to 0, 100, 200, and 400 mg/kg ZnO NPs for 7 days. We explored the underlying mechanisms via the intraperitoneal injection of N-acetyl-cysteine (NAC), an inhibitor of oxidative stress, and salubrinal (Sal), an inhibitor of endoplasmic reticulum (ER) stress.

Results

The results indicated that serum estradiol and progesterone levels declined greatly with increasing ZnO NPs dosage. Hematoxylin and eosin (HE) staining revealed increased atretic follicles and exfoliated follicular granulosa cells. Moreover, at the transcriptional level, antioxidant-related genes such as Keap1 and Nrf2, and ER stress-related genes PERK, eIF2α, and ATF4 were markedly upregulated. In addition, the expression of Caspase12, Caspase9, and Caspase3, which are genes related to apoptosis, was also upregulated in all ZnO NPs treatment groups. Serum malondialdehyde (MDA) content was remarkably up-regulated, whereas superoxide dismutase (SOD) activity was down-regulated. The 400 mg/kg ZnO NPs treatment group suffered the most substantial harm. However, ovarian damage was repaired when NAC and Sal were added to this group.

Conclusion

ZnO NPs had toxic effects on the ovary of female mice, which were due to oxidative stress, ER stress, and the eventual activation of apoptosis.