Comparative morphology of the human’s and laboratory animals’ male reproductive system

The organs of the male reproductive system of laboratory animals are evaluated in studies of reproductive toxicity, they are included in the minimum list in the study of the toxicity of repeated doses of the drug. Accessory sex glands are prone to spontaneous pathologies in laboratory rodents. In addition, animals are a model for the study and development of therapy for diseases of the reproductive system observed in humans, such diseases include epididymoorchitis, autoimmune orchitis, varicocele, prostatitis, prostatic hyperplasia, neoplasms, etc. The presence or absence and the structure of accessory sex glands are specific to each species. This information must be taken into account when planning experiments and identifying pathologies. Therefore, it is important to have knowledge of the morphology of organs in the male reproductive system. The purpose of this review is to systematize basic data on the structure of the organs of the male reproductive system of human and laboratory animals (cynomolgus monkey, dog, cat, pig, ferret, rabbit, rat, mouse, hamster, gerbil and guinea pig), and also compare the morphology of organs to determine similarities and differences in the anatomy and histology of various animal species and human. As part of this review, we have provided information about the organs that participate in toxicity studies. These include the testes, epididymides, and the main accessory sex glands. We also looked at organs that are not usually the subject of scientific research. When comparing the anatomical and histological structure of human and animal testes, specific features were revealed in the population of spermatogenic epithelium, duration of spermatogenesis, morphology of spermatozoa, location of the rete testis, degree of development of interstitial tissue and Leydig cells, thickness of the tunica albuginea, as well as in spatial orientation, color and shape of the testes. There are pronounced species differences in the structure of the accessory sex glands. Externally, the vesicular glands differ in different animal and human species, although their histological structure is the same. In dogs and ferrets, there is only one accessory sex gland — the prostate, in cats — the prostate and bulbourethral glands, the structure of the prostate gland is also very variable. Currently, there is no consensus on the anatomical structure of the prostate gland in rodents such as rats, mice and guinea pigs. There are ampullary glands in the wall of the ampulla of the vas deferens, but they are absent in humans, pigs and cats. In rats and mice, these glands are isolated into separate structures. Preputial glands located in the penis or prepuce area are present in many species, but in rats, mice and hamsters they have acquired a more organized appearance.