Experimental splenic regeneration.

The results of studies which indicate that splenic resection of residual parenchyma is able to regenerate are based primarily upon the weight increase of the splenic remnant at specified times after partial resection. This study was done to determine the histologic characteristics of the residual splenic tissue at 30 and 90 days after partial splenectomy in rats. The average increase in weight of the splenic polar residual after subtotal resection was 43 per cent at 30 days and 44 per cent at 90 days, and 10 per cent at 30 days and 30 per cent at 90 days for residual half spleen after hemisplenectomy. Histologic alterations, mainly present in the parenchyma near the section surface at 30 days were clearly inflammatory secondary to surgical trauma. There was no regenerative significance. At 90 days, the results of histologic study demonstrate a readjustment of the vascular net and the lymphoid tissue of the white pulp. The result is new structures which reproduces the follicular morphologic characteristics. This process requires 90 days to predominate over inflammatory postsurgical changes. Only during this phase may it have an important role in determining the increase of the residual weight. Further research into the functional capacity of the newly formed structures is necessary to confirm that the histologic modifications observed are comparable to true regeneration.