STEREOLOGICAL QUANTITATION OF LEYDIG AND SERTOLI CELLS IN THE TESTIS FROM YOUNG AND OLD MEN

ABSTRACT One of the newer stereological methods, the optical fractionator, was applied to the study of the effects of ageing on the human testis. The estimated total number of Sertoli and Leydig cells per testis in men younger than 30 years were 430×10 6 (CV = SD/mean = 0.35) and 117×10 6 (CV = 0.53), respectively, while in men older than 50 years the estimated total Sertoli cell number was 266×10 6 (CV = 0.46) and the mean Leydig cell number 83×10 6 (CV = 0.53). The difference between the number of Sertoli cells in men younger than 30 years compared with men older than 50 years was close to statistical significance (p = 0.052) while no differences was found in total Leydig cell number (p = 0.22)

Assessment of brain reference genes for RT-qPCR studies in neurodegenerative diseases

Evaluation of gene expression levels by reverse transcription quantitative real-time PCR (RT-qPCR) has for many years been the favourite approach for discovering disease-associated alterations. Normalization of results to stably expressed reference genes (RGs) is pivotal to obtain reliable results. This is especially important in relation to neurodegenerative diseases where disease-related structural changes may affect the most commonly used RGs. We analysed 15 candidate RGs in 98 brain samples from two brain regions from Alzheimer’s disease (AD), Parkinson’s disease (PD), Multiple System Atrophy, and Progressive Supranuclear Palsy patients. Using RefFinder, a web-based tool for evaluating RG stability, we identified the most stable RGs to be UBE2D2, CYC1, and RPL13 which we recommend for future RT-qPCR studies on human brain tissue from these patients. None of the investigated genes were affected by experimental variables such as RIN, PMI, or age. Findings were further validated by expression analyses of a target gene GSK3B, known to be affected by AD and PD. We obtained high variations in GSK3B levels when contrasting the results using different sets of common RG underlining the importance of a priori validation of RGs for RT-qPCR studies