PURPOSE Compare non-parametric permutation method using intr-meal rate as endpoint to existing ANOVA method that uses average daily meal duration as an endpoint for detection of chronic pain in Sprague-Dawley rats. METHODS Nociception following bilateral temporomandibular joint (TMJ) injection of high-dose of Complete Freunds Adjuvant (CFA, 250 μg/50 μL per side) could be detected in young adult male Sprague-Dawley rats using average daily meal durations as a measure of nociception for up to 19 days (Kramer, Kerins, Schneiderman, & Bellinger, 2010) using ANOVA and multiple comparisons range tests. In this study, we reanalyzed the data using a non-parametric permutation procedure based on absolute differences between intra-meal feeding rate curves. In addition, to that experiment, we injected bilaterally the TMJ of naive rats with either a low-dose CFA (15 μg/50 μL per side, n=6) or saline (50 μL of 0.9%, n=4) and monitored the animals for 7 days. RESULTS The permutation test of the intra-meal feeding rate detected the presence of nociception in the high-dose CFA treatment group for up to 40 days or twice as long as when using ANOVA on average daily meal durations. The permutation method also detected the low-dose CFA induced nociception with ten-times lower p-values and for several days longer than ANOVA of changes in meal durations. CFA-induced injury resulted in even reduction of intra-meal feeding rate and lengthening of the meals in both high- and low-dose CFA-injected animals. The rate analysis also showed when the rats first started a meal they were experiencing the same level of nociception as at the end of the meal. This demonstrated that intra-meal chewing itself did not alter the level of nociception. CONCLUSIONS These results suggest that permutation tests based on differences in intra-meal feeding rates can be used as a sensitive test to determine and study the temporal patterns of TMJ nociception.

中文翻译：

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基于距离的餐间差异排列作为大鼠颞下颌关节伤害感受的敏感测试。

目的 将使用餐内速率作为终点的非参数排列方法与现有的使用平均每日进餐时间作为检测 Sprague-Dawley 大鼠慢性疼痛终点的 ANOVA 方法进行比较。方法 可以在年轻成年雄性 Sprague-Dawley 大鼠中检测双侧颞下颌关节 (TMJ) 注射高剂量完全弗氏佐剂 (CFA，每侧 250 μg/50 μL) 后的伤害感受，使用平均每日进餐时间作为伤害感受的量度长达 19 天（Kramer, Kerins, Schneiderman, & Bellinger, 2010），使用 ANOVA 和多重比较范围检验。在这项研究中，我们使用基于餐内喂养率曲线之间的绝对差异的非参数置换程序重新分析数据。此外，在那个实验中，我们用低剂量 CFA（每侧 15 μg/50 μL，n=6）或盐水（50 μL，0.9%，n=4）双侧注射幼稚大鼠的 TMJ，并监测动物 7 天。结果 餐内喂食率的排列测试检测到高剂量 CFA 治疗组存在长达 40 天的伤害感受，或者是使用 ANOVA 平均每日进餐持续时间时的两倍。置换方法还检测到低剂量 CFA 诱导的伤害感受，其 p 值低 10 倍，并且比进餐时间变化的方差分析长几天。CFA 诱导的损伤导致高剂量和低剂量 CFA 注射动物的餐内喂食率甚至延长。速率分析还显示，当老鼠第一次开始用餐时，它们的伤害感受与用餐结束时相同。这表明餐内咀嚼本身并没有改变伤害感受的水平。结论 这些结果表明，基于餐内进食率差异的排列测试可用作确定和研究 TMJ 伤害感受时间模式的敏感测试。