Figure 2.

CNS cytokine and chemokine responses in the brains of mouse-adapted SARS-CoV-2 (MA10) infected laboratory mice. 10-week-old male C57BL/6, BALB/c and Rag2^−/− mice were inoculated via the intranasal route with mock or MA10 strain of SARS-CoV-2 (1 × 10⁵ TCID₅₀). Upon 3 days post-infection (3 dpi), mice were euthanized, and RNA was isolated from the left hemisphere for gene expression analysis. (A) TNF-α and (B) IL-1β mRNA expression in brains of SARS-CoV-2 (MA10) infected C57BL/6J mice did not significantly differ from those of mock-infected mice. (C) Cxcl10; (D) Ccl2 and (E) IL-6 expression in brains of SARS-CoV-2 (MA10) infected Rag2^−/− mice and C57BL/6J mock-treated mice. (F) IL-6 (G) CxCL10 (H) TNF-α expression in BALB/c mice. (I) 21 days post-infection (21 dpi), male mice were euthanized and analyzed for TNF-α mRNA expression in C57BL/6 mice, SARS-CoV-2 MA10 infected C57BL/6 mice show a trend towards increased TNF-α expression compared to mock-treated mice. IL-6 was significantly increased, and TNF-α showed an upward trend in SARS-CoV-2 MA10-infected BALB/c mice compared with mock-treated mice. Data are presented as mean ± SEM. p values represent mock vs. SARS-CoV-2 (MA10) challenged groups. Significant differences are designated using a two-tailed unpaired student t-test for two groups and one-way ANOVA (for more than two groups). Some of the experiment n = 4 indicates 2 mice were excluded because the dissection of half left hemisphere did not align with other mice. C57BL/6J + Mock n = 5; C57BL/6J + SARS-CoV-2 MA10 n = 4; BALB/c + Mock n = 4–5; BALB/c + SARS-CoV-2 MA10 n = 4–5; Rag2^−/− + SARS-CoV-2 MA10 n = 4; * p < 0.05.