Morphology of morphometric indicators of the mutual integration of the adrenal gland and thymus in preterm neonates with respiratory distress syndrome

Purpose: to demonstrate morphologically that the adrenal gland and thymus function as a single neuroen­docrine-immune (stress-adaptive) system in preterm neonates against the background of respiratory distress syn­drome (RDS). Material and methods – microspecimens of the adrenal gland and thymus obtained from deceased preterm neonates with RDS were scanned on NanoZoomer medical equipment (HAMAMATSU PHOTONICS, Japan); two-dimensional microimages were processed with QuPath-0.4.0 software (NanoZoomer Digital Pathology Image). Cell size, nuclear-cytoplasmic index, area occupied by interstitial tissue, thickness of all histological zones of the cor­tical layer, and the area occupied by blood vessels were determined (at 200× magnification). The interrelation of the adrenal gland and thymus against the background of RDS was analysed across two age periods – early neonatal (0–7 days) and late neonatal (8–28 days). Quantitative indicators were processed by descriptive and variational statistics (MS Office Excel, STATISTICA for Windows 10); Student's t-test, Pearson and Spearman correlation coefficients and the χ² test were used; results are presented as M±m at a significance level of P<0.05 (P<0.001 for some indicators). Results – it was morphologically proven that the adrenal gland and thymus function as a single neuroendocrine-immune (stress-adaptive) system: cortisol released by the adrenal gland induces thymocyte apoptosis, the rate of which rose from ~5% in controls to 54.8% in RDS at 0–7 days of age. Conclusion – this proves the pathogenetic interrelation of the two organs.