| Objective To investigate the intensity of the host versus graft reaction (HVGR) at different stages after allogeneic/autologous transplantation in rats with large full-thickness cartilage defects, and to guide experimental studies.Methods Thirty-six healthy adult male SD rats were randomly assigned to three groups: An untreated control group, an autologous transplantation group, and an allogeneic transplantation group. Rats were sacrificed on days 3, 5, and 7 postoperatively. Blood and spleen cells were collected for flow cytometry and ELISA analysis. Bone tissue sections from the transplantation sites were stained with hematoxylin-eosin (HE). The results of the inflammatory response, including changes in inflammatory cell populations analyzed by flow cytometry and levels of inflammatory factors measured by ELISA, were subjected to statistical analysis.Results After implantation of different grafts at the cartilage defect site in the model, the expression of monocytes and NK cells in the blood samples of rats in the allograft group was significantly increased at both 3 and 5 days after surgery. Notably, the monocyte counts in this group peaked at day 5, and was significantly higher than that in the other two groups. In the spleen, NK cell expression was also higher in the allograft group on days 3 and 5 compared to the blank control and autograft groups. At the first sampling on day 3, the expression of Tregs in the autograft group was higher than in the other two groups, and this result was statistically significant on days 5 and 7 (P<0.05). In the allograft group, the expression levels of monocytes and T cells were higher on days 5 and 7 than on day 3. Tissue staining results indicated significant local inflammation on day 3 after surgery. Stained sections prepared on days 5 and 7 showed that the immune response peaked on day 5. ELISA results revealed that the levels of IL-1β, IL-6, and TNF-α in the peripheral blood of rats in the allograft group were significantly higher than those in the other two groups after surgery (P<0.05).Conclusion The intensity of the host's response to allogeneic full-thickness cartilage grafts increases progressively, peaking within 5 days after transplantation, and then gradually declines. This study provides temporal evidence of the acute immune response following homograft full-thickness cartilage transplantation, offering valuable insights for the clinical application of full-thickness cartilage grafting. |
