The impact of dioctyl phthalate exposure on multiple organ systems and gut microbiota in mice

Abstract

Dioctyl phthalate, commonly known as bis(2-ethylhexyl) phthalate (DEHP), is a widely used plasticizer in various industries and has been shown to directly or indirectly impact human health. However, there is a lack of comprehensive studies evaluating the potential health risks associated with DEHP accumulation in different organs across various age groups. This study aimed to assess the effects of low (50 mg/kg·bw) and high (500 mg/kg·bw) doses of DEHP on five different organs in mice at young (4-week-old) and aged (76-week-old) life stages. Our findings revealed that both low and high doses of DEHP exposure led to significant dose-dependent inflammation in the liver, spleen, and kidney. Furthermore, regardless of age, DEHP exposure resulted in elevated activity of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in the liver, as well as increased levels of creatinine (Cr) and urea in the kidney. Moreover, analysis of the fecal microbiota using 16S rRNA sequencing demonstrated that DEHP exposure disrupted the homeostasis of the gut microbiota, characterized by an increased abundance of pathogenic bacteria such as Desulfovibrio and Muribaculum, and a decreased abundance of beneficial bacteria like Lactobacillus. This study provides compelling evidence that DEHP at different concentrations can induce damage to multiple organs and disrupt gut microbiota composition. These findings lay the groundwork for further investigations into DEHP toxicity in various human organs, contributing to a better understanding of the potential health risks associated with DEHP exposure.

Keywords: DEHP; Gut microbiota; Inflammation; Organs; Toxicity.

Fig. 1

Body and liver weight of mice under different doses of DEHP for 12 weeks. (A) Body weight, (B) Liver weight, (C) the Liver body weight ratio, (D) appearance of hepatic tissue, (E) representative photomicrographs of hepatic tissue (H&E staining; magnification × 200), and (F) liver function of mice in each group at 12 weeks. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. The arrow indicates the site of injury.

Fig. 2

Spleen damage of mice exposed to different doses of DEHP at different ages for 12 weeks. (A) Spleen weight, (B) Spleen index, and (C) Representative photomicrographs of H&E staining (magnification, × 200) of the spleen of mice in each group at 12 weeks. *P < 0.05, **P < 0.01, ***P < 0.001. The arrow indicates the site of injury.

Fig. 3

Kidney damage of mice exposed to different doses of DEHP at different ages for 12 weeks. (A) H&E staining of renal tissue (magnification, × 200) and (B) kidney index of mice in each group at 12 weeks. *P < 0.05，**P < 0.01. The arrow indicates the site of injury.

Fig. 4

Ileum damage of mice exposed to different doses of DEHP at different ages for 12 weeks. (A) H&E staining of the ileum (magnification, × 200), (B) Serum DAO, and (C) Serum d-lactate level of mice. *P < 0.05. The arrow indicates the site of injury.

Fig. 5

Distribution and composition of gut microbiota of mice exposed to DEHP at a different ages for 12 weeks. Principal coordinate analysis (PCoA) of genus level in (A) young group and (B) old group. Taxonomic composition at the phylum level in (C) young and (D) old groups. The ratio of Firmicutes and Bacteroidetes in the gut microbiota of (E) young and (F) old groups.

Fig. 6

The gut microbiota of mice exposed to different DEHP doses to varying ages by 16S rRNA gene sequencing. Taxonomic composition at the genus level in (A) young and (B) old groups. LDA value distribution histogram of (C) YC and YL groups, (D) YC and YH groups, (E) OC and OL groups, and (F) OC and OH groups.