Here we investigated the morphology, quantity, distribution and gene expression of mechanoreceptors in the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), lateral collateral ligament (LCL), patellar tendon (PaT) and popliteal tendon (PoT) of the knee joint. Twelve 6-month-old rabbits were divided into two groups. In one group, the ACL, PCL, MCL, LCL, PaT and PoT were collected to observe the morphology, distribution and quantity of mechanoreceptors. In another group, the ACL, PCL, MCL, LCL, PaT and PoT of bilateral knee joints were used to determine S100B, CGRP and NEFM gene levels. Five types of mechanoreceptors were observed including Ruffini corpuscles, Pacinian corpuscles, Golgi-tendon bodies, atypical mechanoreceptors and free nerve endings. The total amount of mechanoreceptors was significantly lower in MCL, LCL, PaT and PoT as compared with ACL and PCL (P < 0.001). All examined mechanoreceptors were present in ACL, PCL and LCL. However, no Pacinian corpuscles and Golgi-tendon bodies were found in MCL and PoT as well as Pacinian corpuscles were not observed in PaT. The present study indicated that the levels of NEFM was significantly lower in PCL, MCL, LCL, PaT and PoT as compared with ACL (P < 0.05), but there was no significant difference in CGRP level between ACL and other ligaments except LCL (P > 0.05). Thus, the quantity, type and gene expression of mechanoreceptors are different in various ligaments. Thus, the quantity and distribution of mechanoreceptors may be related to ligament's function.

中文翻译：

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兔膝关节韧带和肌腱中机械感受器的分布，数量和基因表达

在这里，我们研究了前交叉韧带（ACL），后交叉韧带（PCL），内侧副韧带（MCL），外侧副韧带（LCL），tell腱（PaT）和肌腱的机械感受器的形态，数量，分布和基因表达。膝关节的腱（PoT）。将12只6个月大的兔子分成两组。在一组中，收集ACL，PCL，MCL，LCL，PaT和PoT来观察机械感受器的形态，分布和数量。在另一组中，双侧膝关节的ACL，PCL，MCL，LCL，PaT和PoT用于确定S100B，CGRP和NEFM基因水平。观察到五种类型的机械感受器，包括鲁菲尼小体，帕西尼亚小体，高尔基腱组织，非典型机械感受器和自由神经末梢。与ACL和PCL相比，MCL，LCL，PaT和PoT中机械感受器的总量显着降低（P  <0.001）。所有检查的机械感受器均存在于ACL，PCL和LCL中。但是，在MCL和PoT中未发现Pacinian小体和高尔基腱组织，在PaT中未发现Pacinian小体。本研究表明PCL，MCL，LCL，PaT和PoT中NEFM的水平显着低于ACL（P  <0.05），但CGRP没有明显差异ACL与除LCL以外的其他韧带之间的水平（P  > 0.05）。因此，在不同的韧带中，机械感受器的数量，类型和基因表达是不同的。因此，机械感受器的数量和分布可能与韧带的功能有关。