Statistical analysis
Results are expressed as mean ± standard deviation. Student’s t-test was used to measure the statistical significance between two groups. One-way ANOVA followed by Dunnett’s post-hoc test was used to measure the statistical difference between three or more groups. P< 0.05 was considered to indicate a statistically significant difference. Asterisks are used to indicate P values as follows: *, P < 0.05; **, P < 0.01; ***,P < 0.005, ****, P < 0.0005.