Figure 2. Six3-Cre;Lhx1lox/lox Circadian Behavior and SCN Clock Are Susceptible to Heat.
(A-C) Sample CBT recordings from control (A), Six3-Cre;Lhx1lox/lox (B), and Vip−/− (C) mice in DD, before and after 3X (long red rectangle), and 1X (red square) LPS injections.
(D-E) Sample CBT recordings from control (D), Six3-Cre;Lhx1lox/lox (E), and Vip−/− (F) mice in DD, before and after 3X saline injections (red rectangle).
(G) Bar graph showing period of control (black), Six3-Cre;Lhx1lox/lox (blue), and Vip−/− (green) mice before and after 3X LPS, 1X LPS, and 3X saline (Supplemental Data Set; two-way ANOVA with Tukey post-hoc tests; ***p<0.001; mean +/− SEM; only within-genotype comparisons to baseline are shown).
(H) Bar graphs showing the number of control (black), Six3-Cre;Lhx1lox/lox (blue), and Vip−/− (green) mice that had singly rhythmic, multiply rhythmic, or arrhythmic CBTs before and after 3X LPS, 1X LPS, and 3X saline (Supplemental Data Set; 2x3 Fisher’s exact test; *p<0.05; only within-genotype comparisons to baseline are shown).
(I) Background-subtracted Per2::Luc bioluminescence traces from Lhx1lox/lox (black) or Six3-Cre;Lhx1lox/lox (blue) SCN, before and after a single 3-hour 38.5°C heat pulse (yellow square).
(J) Phase shifts of Per2::Luc rhythms after a single 3-hour 38.5°C heat pulse in Lhx1lox/lox (black), Six3-Cre;Lhx1lox/lox (blue), wild type (gray), and wild type + 1mM TTX (red) SCN (n=7,4,7,6; one way ANOVA with Tukey post-hoc; ***p<0.001; mean +/− SEM).
(K-M) Background-subtracted Per2::Luc bioluminescence traces of Lhx1lox/lox (black, K), rhythmic Six3-Cre;Lhx1lox/lox (blue, L), or arrhythmic Six3-Cre;Lhx1lox/lox (blue, M) SCNs. SCNs received 3X 3 hour, 38.5°C heat pulses (yellow squares). This treatment merely phase-shifted Six3-Cre;Lhx1lox/lox slices rhythmic at baseline (L), but was able to induce rhythms in Six3-Cre;Lhx1lox/lox slices arrhythmic at baseline (M).
See also Figure S2 and Supplemental Data Set.