Fig 2: PLE attenuates SARS-CoV-2-induced lung injury and biochemical alterations in the hamster model: summary of the main findings. Experimental infection with SARS-CoV-2 elicited an inflammatory response in lung tissues as reflected by an increased number of Iba-1-positive macrophages and MPO-positive neutrophils. A higher number of cells expressing Mx1 and the proliferation marker Ki-67 was also evident. However, no alterations in the number of CD3-positive T cells were observed. Treatment with PLE reduced SARS-CoV-2-induced lung injury and alterations in biochemical markers. In addition, we found a significant inhibition of viral replication, as reflected by a reduced NP expression.

Fig 3: Representative immunohistochemical staining for uPA and MPO, CD68, CD3, or CD20 in inflamed colorectal tissue from UC patients using mirror sections obtained from two serial sections mounted on glass slides with the same cut surface facing upward. One section was stained using anti-uPA antibody and the other with anti-MPO (A), anti-CD68 (B), anti-CD3 (C), or anti-CD20 antibody (D). Each section was incubated with primary antibody and subsequently with polymer reagent and visualized by DAB chromogen. Scale bar, 50 μm.

Fig 4: PLE attenuates SARS-CoV-2-induced immune cell infiltration in hamsters which had undergone a low-dose SARS-CoV-2 challenge. Immunohistochemistry was applied to investigate the lung tissue expression of Iba-1, MPO, Ki-67, CD3, and Mx1. The number of antigen-positive cells identified on lung sections was normalized to the total number of cells using an Aperio Imagescope v12.3. Data are expressed as means ± standard errors of the mean. Statistical significance was determined by a one-tailed Student’s t-test. *p < 0.05.