Age-dependent slowing of enteric axonal transport in insulin-resistant mice

Figure 3 Number of fluorogold-labeled neurons in enteric neural pathways in 4-32 wk old KK and KKAy mice. A: Long ascending pathway: The number of fluorogold (FG)-labeled neurons was significantly decreased in KKAy as compared to KK mice [main effect: F (1, 53) = 8.136, P = 0.006]. The numbers of FG-labeled neurons began to decrease with age in KK and KKAy mice at 16 wk of age with the fewest neurons detected at 24 wk of age [main effect: F (4, 53) = 24.936, P < 0.001]; B: Short ascending pathway: There was a trend for the numbers of FG-labeled neurons to be reduced in KKAy as compared to KK mice [main effect: F (1, 53) = 2.940, P = 0.092]. The number of FG-labeled neurons decreased with age in KK and KKAy mice [main effect: F (4, 53) = 17.188, P < 0.001]. By 16 wk of age, the numbers of FG-labeled neurons were reduced and remained low; C: Fundus: Similar numbers of FG-labeled neurons were observed in KK and KKAy mice [main effect: F (1, 53) = 2.464, P = 0.122]. In KK and KKAy mice, the numbers of labeled FG neurons were highest at 8 wk and lowest at 24 and 32 wk [main effect: F (4, 53) = 5.195, P = 0.001]; D: Long descending pathway: Similar numbers of FG-labeled neurons were observed in KK and KKAy mice [main effect: F (1, 57) = 0.922, P = 0.341]. By 32 wk of age, the numbers of FG-labeled neurons were reduced as compared to younger ages [main effect: F (4, 57) = 2.944, P = 0.028]; E: Short descending pathway: Similar numbers of FG-labeled neurons were observed in KK and KKAy mice [main effect: F (1, 57) = 2.374, P = 0.129]. The numbers of FG-labeled neurons began to decrease in KK and KKAy mice at 16 wk of age with the fewest neurons detected at 24 wk of age [main effect: F (4, 57) = 9.336, P < 0.001]; F: Antrum: Similar numbers of FG-labeled neurons were observed in KK and KKAy mice [main effect: F (1, 57) = 0.728, P = 0.397]. By 16 wk of age, the numbers of FG-labeled neurons were reduced as compared to 4 and 8 wk of age [main effect: F (4, 57) = 8.920, P < 0.001]. ^aP < 0.05, ^bP < 0.01 vs 4 wk; ^cP < 0.05, ^dP < 0.01 vs 8 wk; ^eP < 0.05 vs 16 wk.