Supplemental Figure 2 - Sex differences in CFA Hypersensitivity & Recovery

Published Image

Figure S2. Sex differences in hypersensitivity caused by CFA injection. (A) Female mice exhibit more sensitivity than males 24 hours after CFA, but less sensitivity than males 3 days post administration. (B) CFA induced more robust sensitivity in female mice than males at the 24 hour post injection timepoint, relative to the individual baseline measurements. (C) Female mice exhibited a greater resolution of sensitivity than did males between the first two post CFA VF measurements. Data expressed as mean value +/- SEM, *** indicates p < 0.001, ** indicates p < 0.01, * indicates p < 0.05.

Statistics

# Raw VF values - stats
a <- CFAs_left %>%
  melt(id.vars=c("ID","Sex","CFA")) 

b <- a %>%
  group_by(variable) %>%
  pairwise_t_test(value~Sex)

tt(b)

variable	.y.	group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
Baseline	value	Male	Female	16	16	0.5710	ns	0.5710	ns
24 hr	value	Male	Female	16	16	0.0170	*	0.0170	*
3 days	value	Male	Female	16	16	0.0288	*	0.0288	*
7 days	value	Male	Female	16	16	0.1940	ns	0.1940	ns

• There were no sex differences in basal paw withdrawal thresholds (p = 0.57)
• 24 hours post CFA, female mice had lower paw withdrawal thresholds than males(p - 0.017)
• 3 days post CFA, female mice had higher paw withdrawal thresholds than females(p=0.028)

# % Baseline Stats
a <- CFAs_left %>%
  mutate(`24 hr` = (`24 hr` / `Baseline`) * 100) %>%
  mutate(`3 days` = (`3 days` / `Baseline`) * 100) %>%
  mutate(`7 days` = (`7 days` / `Baseline`) * 100) %>%
  mutate(Baseline = 100) %>%
  melt(id.vars=c("ID","Sex","CFA")) %>%
  filter(CFA == "CFA")

b <- a %>% 
  group_by(variable) %>%
  pairwise_t_test(value~Sex)

tt(b)

variable	.y.	group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
24 hr	value	Male	Female	16	16	0.0023	**	0.0023	**
3 days	value	Male	Female	16	16	0.0606	ns	0.0606	ns
7 days	value	Male	Female	16	16	0.1470	ns	0.1470	ns

• at the 24 hour timepoint, the % baseline value for female CFA-injected mice was lower than for CFA-injected males (p = 0.0023)

• Three and Seven days post-injection, there was no sex difference in the % baseline (p = 0.061, p = 0.15, respectively).

These findings suggest that there may be sex differences in the timecourese of recovery after CFA injection in our model. Females initially exhibit more robust sensitivity at the site of CFA injection compared to males, but exhibit more recovery than males during the following 48 hour interval.