Fig 1: Effects of bariatric surgery and alpha-ketoglutarate (AKG) administration on selected tight junction proteins of the intestinal barrier. (A) Representative images of the immunolocalization and distribution of claudin 3, MD3, occludin and Zo-1 in the rat duodenum. C—control group undergoing sham surgery; O—group undergoing gastric bypass surgery; O + AKG—group undergoing gastric bypass surgery and receiving alpha-ketoglutarate (AKG); AKG—group undergoing sham surgery and receiving alpha-ketoglutarate. AKG was administered at a dose of 0.2 g/kg/body weight/day in drinking water. All the scale bars represent 50 µ. (B) The bar graph shows the integrated intensity of immunoreactions, measured by comparing pixel brightness values adjusted to DAB staining color detection and inverted 8-bit grayscale, such that a higher pixel value reflects a higher immunoreaction intensity. Different letters above the bars indicate significant differences at p < 0.05, and colors are used to indicate the corresponding tight junction protein.