Figure 3
THC counteracts the effects of aging on the level of spine dynamics. Percentage of spines that were lost (a) or gained (b). (c) Turnover ratio—number of lost and gained spines between two consecutive time points divided by the total number of spines in both time points. (d) Percentage of spines that were stable between two consecutive time points. Spine dynamics from day 13 to day 16 of the treatment. For 3-month-old mice (n = 7 ROIs), for 18-month-old mice (n = 12–20 ROIs / treatment). Each data point represents one ROI. Data was analyzed using one-way ANOVA and Dunnett’s multiple comparison test for comparison of 3-months old vehicle group with the 18-month-old vehicle and THC-treated groups. Differences between the 18-month-old vehicle and THC groups were detected using unpaired t-test. (a) Group effect F2,36 = 4.755, p = 0.0147 (3- vs. 18-month-old vehicle p = 0.0129); 18-month-old vehicle vs. THC t30 = 2.321, p = 0.0273; (b) group effect F2,36 = 2.244, p = 0.1207; (c) group effect F2,36 = 3.462, p = 0.0422 (3- vs. 18-month-old vehicle p = 0.0644); 18-month-old vehicle vs. THC t30 = 2.241, p = 0.0326 (d) group effect F2,36 = 4.755, p = 0.0147 (3- vs. 18-month-old vehicle p = 0.0129); 18-month-old vehicle versus THC t30 = 2.321, p = 0.0273. (e) Survival probability of spines that were gained between day 7 and day 10 (dashed line) of the treatment and all spines that were present at day 10 (full line). THC treatment elevated spine survival of all spines in old mice to the level of young vehicle-treated mice; while spine survival in vehicle treated old mice was significantly reduced (all spines 3- vs. 18-months-old vehicle groups: p = 0.0023). THC-treatment also increased the survival of gained spines notably in comparison to the 3-months-old vehicle group (3-month-old vehicle group vs. 18-month old THC group: p = 0.0076). For survival probability analysis Kaplan–Meier plot and log rank test (Mantel-Cox test) were used. Grey box indicates the treatment duration. Error bars indicate mean ± SEM; * P < 0.05, ** P < 0.01, *** P < 0.001. ns. - not significant.
