Fig. 5.

SARS-CoV-2 infection aggregated activation of α-SMA and accumulation of collagen fibers from the NHP pancreatic tissues of the elder COVID-19 model. Pancreatic tissue sections from the elder control NHP samples were stained by multi-label immunofluorescence (IF) for COL1A1 (CL, yellow), α-SMA (α, red), Ki67 (K, magenta), SARS-CoV-2 S1 protein (S, cyan), insulin (β, green), and CD31 (CD, white). Scale bars, 200 μm. Representative multi-label IF image from the magnified section of (a). Scale bars, 20 μm. The pancreatic tissue section from one elder NHP model sample was stained by the same multi-label makers in (a). Scale bars, 400 μm. Representative multi-label IF image from the magnified section of (c). Inset highlights proliferating collagen fibers dividing the exocrine and endocrine pancreatic tissues into various islands. Scale bars, 20 μm. e Pancreatic tissue section from another elder prototypic SARS-CoV-2 strain-infected NHP model sample was stained by the same multi-label makers in (a). Scale bars, 800 μm. f, g Representative multi-label IF image from the magnified section of (e). Inset highlights co-localization of SARS-CoV-2 viral antigen and accumulated collagen fibers in damaged islet insulin⁺ β cells. Scale bars in f 40 μm. Scale bars in g 20 μm. h–k Quantification of the percentage of COL1A1⁺, α-SMA⁺, Ki67⁺, and CD31⁺ cells, as well as insulin⁺COL1A1⁺, insulin⁺ α-SMA⁺, and S protein⁺ CD31⁺ cells, in the elder control NHPs (3 slides) and elder COVID-19 NHP model (4 slides) (n = 10 images examined from all slides /group). Data are presented as mean ± SD. p Values were calculated by unpaired two-tailed Student’s t test. *p < 0.05, **p < 0.01, and ***p < 0.001