ABSTRACT
Objective To observe homing of mesenchymal stem cells (MSCs) in immune organs and inflammatory joints in collagen induced arthritis(CIA) rats. MethodsRats MSCs were isolated and expanded from bone marrow cells by density gradient centrifugation and adhering to the culture cell walls, and the phenotypes were assessed by flow cytometry. MSCs were labeled by PKH-26 and Brdu. Sixty-four rats were randomly divided into normal group and CIA group. Every 8 rats were sacrificed at 3, 11, 30, 42 days after transplantation of MSCs. At the end of the experiment, the specimens of thymus gland, spleen, ankle joints were exposed, fixed, decalcified, wrapped and cut into slices. Confocal laser scanning microscope and immunohistochemical method were used to observe migration and distribution of MSCs in different organs. Independent samples group t test with SPSS 12.0 software package was used for statistical analysis. ResultsIt was found that allogenic MSCs could stay in spleen, thymus gland and joints of CIA rats for a relatively long period (42days). Forty-two days after transplantation of MSCs, the average grey scale values of spleen and thymus gland in CIA group(37.5±8.8, 29.9±5.9 respectively) were significantly higher than the normal group(16.0±2.3,13.2±4.3 respectively), the average grey scale values of ankle joints in CIA group 78±8 was significantly lower than the normal group 93±14(P<0.05). ConclusionIt has been found that MSCs can stay in the injured tissue and organs preferentially.