Fig. 3

Porphyromonas gingivalis (P. gingivalis) bacteremia promoted the formation of caveolae-like structures but did not influence the intercellular junctions of microvessels in the rat brain tissues. a Representative images of ultrastructure in the hippocampus and cortex microvessels. Transmission electron microscopy (TEM) showed that the numbers of vesicles in the hippocampus and cortex microvessels increased in the high-intensity group compared to the control group, while no obvious damage was observed in the microvascular wall structure in the hippocampus and cortex tissues. (▲ indicates vesicle and caveolae-like structures. Scale bar, 2 μm and 500 nm). I and I': Hippocampus microvessels in the control group. II and II': Hippocampus microvessels in the high-intensity group. III and III': Cortex microvessels in the control group. IV and IV': Cortex microvessels in the high-intensity group. b Immunohistochemical staining and quantification showed that Caveolin-1 (Cav-1) expressions in the hippocampus (III and III') and cortex microvessels (IV and IV') in the high-intensity group significantly increased compared to those of the corresponding control groups (I, I', II, and II'). V and VI: Quantification of Cav-1 average optical density in the hippocampus and in the cortex. The red arrows indicated Cav-1 staining in BMECs of microvessels. c Western blot and quantification showed that the expression of Occludin (OCLD) protein did not significantly change in the brain tissues of rats with P. gingivalis bacteremia. I and II: The OCLD protein expression and quantification in the hippocampus. III and IV: The OCLD protein expression and quantification in the cortex. ^*P < 0.05. High: the high-intensity group. Values are expressed as the mean ± standard deviation. The results represent three independent experiments