Differential cytokine expression in gastric tissues highlights helicobacter pylori's role in gastritis

Abstract

Helicobacter pylori (H. pylori), known for causing gastric inflammation, gastritis and gastric cancer, prompted our study to investigate the differential expression of cytokines in gastric tissues, which is crucial for understanding H. pylori infection and its potential progression to gastric cancer. Focusing on Il-1β, IL-6, IL-8, IL-12, IL-18, and TNF-α, we analysed gene and protein levels to differentiate between H. pylori-infected and non-infected gastritis. We utilised real-time quantitative polymerase chain reaction (RT-qPCR) for gene quantification, immunohistochemical staining, and ELISA for protein measurement. Gastric samples from patients with gastritis were divided into three groups: (1) non-gastritis (N-group) group, (2) gastritis without H. pylori infection (G-group), and (3) gastritis with H. pylori infection (GH-group), each consisting of 8 samples. Our findings revealed a statistically significant variation in cytokine expression. Generally, cytokine levels were higher in gastritis, but in H. pylori-infected gastritis, IL-1β, IL-6, and IL-8 levels were lower compared to H. pylori-independent gastritis, while IL-12, IL-18, and TNF-α levels were higher. This distinct cytokine expression pattern in H. pylori-infected gastritis underscores a unique inflammatory response, providing deeper insights into its pathogenesis.

Keywords: Helicobacter pylori; Cytokines; ELISA; Gastritis; H&E staining; Immunohistochemical staining; Inflammation; RT-qPCR.

Figure 1

Expression of genes for cytokines in human gastric tissues. The mRNA expression of Interleukin (IL)-1β, IL-6, IL-8, IL-12, IL-18 and tumour necrosis factor (TNF)-α in the normal group (N-group), gastritis without H. pylori infection group (G-group) and gastritis with H. pylori infection group (GH-group). Target gene expression was calculated with reference to the expression levels of β-actin. A histogram presents data with an error bar (mean ± SD, n = 8/group, *P < 0.05, ** P < 0.01, ***P < 0.001, **** P < 0.0001).

Figure 2

Immunohistochemistry of the gastric mucosa. (A) Representative IHC images Interleukin (IL) -1β, IL-6, IL-8, IL-12, IL-18, and Tumor necrosis factor-α (TNF-α). (B-G) Quantitative analysis of IL-1β, IL-6, IL-8, IL-12, IL-18, and TNF-α expression in gastric mucosa. The data are expressed as the means ± SD (n = 8/group). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. N-group, normal group; G-group, gastritis without H. pylori infection; GH-group, gastritis with H. pylori infection. IM1: intestinal metaplasia; APG: atrophy of pyloric gland; HP: Helicobacter pylori.

Figure 3

Quantitative analysis (ELISA) of Interleukin-1β (IL-1β), IL-6, IL-8, IL-12, IL-18 and tumor necrosis factor (TNF)-α. The expression of proteins was normalised to unit protein concentration. The histogram presents data with an error bar. (Mean ± SD, n = 8/group, *P < 0.05, ** P < 0.01, ***P < 0.001, **** P < 0.0001). N-group, normal group; G-group, gastritis without H. pylori infection; GH-group, gastritis with H. pylori infection.