Effect of atorvastatin on spermatogenesis in rats: A stereological study

Purpose: To investigate the effects of oral atorvastatin on spermatogenesis in a rat model.Methods: Rats were equally assigned into control and study groups, the latter receiving atorvastatin (20 mg/kg/day). At the end of 12 weeks, spermatogenetic activity was evaluated using stereological and optical fractionator methods. Serum follicle-stimulating hormone (FSH), total testosterone (TT), and luteinizing hormone (LH) levels were measured using micro–ELISA kits. Total cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL - C), and high-density lipoprotein cholesterol levels were also measured by enzymatic colorimetric assays.Results: Testicular stereological analysis revealed that atorvastatin reduced Sertoli cell numbers (p < 0.001), spermatogonia (p < 0.001), spermatocytes (p < 0.001), and seminiferous tubule diameters (p < 0.001). LDL – C (p = 0.01) and TG (p = 0.01) values were significantly lower in the study group compared with the control group. There was no significant difference in FSH (p = 0.44), LH (p = 0.48),and TT (p = 0.06) levels between the groups.Conclusion: The findings show that atorvastatin causes deleterious effects on rat spermatogenesis. It should therefore be used with caution in clinical practice owing to its potential adverse effects, especially on male fertility. Keywords: Statin, Atorvastatin, Spermatogenesis, Stereology, Testis

ESTIMATION OF THE NUMBER OF NEURONS IN THE HIPPOCAMPUS OF RATS WITH PENICILLIN INDUCED EPILEPSY

Epilepsy is a neurological disease arising from strong and uncontrollable electrical firings of a group of neurons in the central nervous system. Experimental epileptic models have been developed to assess the physiopathology of epileptic seizures. This study was undertaken to estimate the number of neurons in the rat hippocampus with penicillin induced epilepsy, using a stereological method, "the optical fractionator". In the experimental group, 500 IU penicillin-G was injected intra-cortically, and in the control group, the same volume of saline was administered. A week later, the animals were decapitated and their brains were removed by craniatomy. Frozen brains were cut with a thickness of 150 ěm in a cryostat. Sections were collected by systematic random sampling and stained with hematoxylen-eosin. Microscopic images of pyramidal cell layers from hippocampus CA1, CA2 and CA3 subfields were then transferred to a monitor, using a 100x objective (N.A. = 1.25). Using the optical disector method, the neurons were counted in the frames and determined with a fractionator sampling scheme. The total pyramidal neuron number was then estimated using the optical fractionator method. The total pyramidal neuron number was found to be statistically lower in the experimental group (mean = 142,888 ± 11,745) than in the control group (mean = 177,953 ± 10,907) (p < 0.05). The results suggest that a decrease in the hippocampal neuronal number in a penicillin model of epilepsy can be determined objectively and efficiently using the optical fractionator method.

MODERN STEREOLOGICAL EVALUATION IN THE AGING HUMAN SUBSTANTIA NIGRA

Quantitative estimation of neuronal numbers in the human substantia nigra (SN) can be achieved by a conventional single section (SS) count or by the more modern stereological disector (DS) count. However, counting results from SS counts are potentially biased and might not accurately reflect the total neuronal number in the SN or the changes in the total number of neurons occurring during aging or with neurodegenerative disease. Potential sources of bias include the lack of linearity between cell number per area of section and cell number per volume; the variation in the counting level and orientation of tissue sections; and shrinkage of tissue. Modern stereological DS counting overcomes these problems and has played a crucial role in many recent studies in neuropathology, neuroanatomy, neuropharmacology and neurogenetics. Over the past decades, four stereology based counting methods including physical DS, physical fractionator, optical DS and optical fractionator, have been established for quantitative measurement. Recently, stereological estimates have revealed a linear reduction rate of total nigral neuronal numbers with age of about 10% per decade. These findings suggest that the surviving nigral neurons undergo a degenerative change leading to neuronal dysfunction with aging. Furthermore, as an advanced quantitative tool, modern stereological evaluation may provide new insights into the aging of the human SN thereby enabling us to better understand the pathophysiological processes in aging brain.