Transcription profiling of rat to study the effect of hindlimb unloading on healing of medial collateral ligaments 3 weeks after injury

A recent physiological study established that hindlimb unloading of rats at 3 and 7 weeks inhibits healing of injured ligaments resulting in a badly aligned discontinuous collagen matrix. Using tissue from these rats we focused on the 3-week time point employing microarray analysis to identify what cellular processes or lack of processes could account for these observed deficiencies. We used the Affymetrix RG_U34A GeneChip and performed image analysis with Microarray Suite 5.0. For normalization we used the MAS global normalization protocol with a default target mean signal of 500. Gene expression in medial collateral ligament tissue under 4 different treatment conditions was measured: loaded control loaded wound healing unloaded control and unloaded wound healing. From our results it appears that unloaded tissue lags behind loaded tissue in its progression through the healing process and at 3 weeks is still engaged in the proliferative phase whereas loaded tissue is actively remodeling its collagen matrix.

近期一项生理学研究证实，在3周和7周时对大鼠后肢进行卸载处理，会抑制受损韧带的愈合，导致胶原基质严重错位且不连续。利用这些大鼠的组织样本，本研究聚焦于3周这一时间点，通过微阵列分析，旨在识别哪些细胞过程或过程的缺失可以解释这些观察到的缺陷。研究采用了Affymetrix RG_U34A基因芯片，并使用Microarray Suite 5.0进行图像分析。在标准化处理中，采用了MAS全局标准化协议，目标平均信号值为500。对内侧副韧带组织在四种不同治疗条件下的基因表达进行了测量：加载对照、加载伤口愈合、未加载对照以及未加载伤口愈合。从我们的研究结果来看，未加载组织在愈合过程中的进展滞后于加载组织，在3周时仍处于增殖阶段，而加载组织则正处于积极重塑其胶原基质的过程中。