Postnatal histogenesis of islets of langerhans in rat

The current study was carried out to analyze the process of growth, differentiation and development of alpha and beta cells of pancreatic islet during early post-natal period. Pups born 22-23 days postcoitum were divided into two groups A & B, having ten pups each. Group A pups were sacrificed on day 2 postnatal and group B on day 7 postnatal to obtain pancreatic tissue. Adult animals (10-12 weeks) were taken as group C. In both postnatal groups Islets of Langerhans were observed as groups of light staining cells in well-developed acinar parenchyma however, group B pancreatic tissue was comparable to adult tissue. Both groups showed strong association of pancreatic tissue with developing ducts whereas, group A showed mesenchymal tissue present in the vicinity of developing islets. Quantitative variables were applied and compared using one way ANOVA. The mean of islets per section for group A was 6.3 plus minus 1, for group B 7.8 plus minus 1 and for group C 3.1 with significant difference among the groups (p less than 0.05). The mean of the diameter of an islet was 112 plus minus 1for group A. 136 plus minus 2 for group B, and 171 plus minus 5 for group C with statistically significant difference among the groups. Total number of cells per islet did not show statistically significant difference (p greater than 0.05). Number of beta cells per islet was 95 plus minus 2 for group A, 76 plus minus 4 for group B and 102 plus minus 3 for group C, which was statistically significant (p less than 0.05), Number of a cell per islet and the ratio of beta and alpha cell was not statistically significant among the groups. To conclude, all the parameters which were studied increased gradually postnatally. Number of islets though decreased but the diameter of islets increased gradually. Both postnatal groups showed ductal epithelium as well as mesenchymal tissue association with histogenesis of islets.