[Histological and histomorphometric examination of tibiae of Mongolian gerbils Meriones unguiculatus of different age as possible objects in space experiments].

Histological and histomorphological examinations of tibiae taken from young (body mass = 27 g) and adult (body mass = 73 g) male Mongolian gerbils Meriones unguiculatus was fulfilled. Tibial bones of Mongolian gerbils have a hockey-stick form and are extremely thin. Morphologically the gerbil's tibial bone is very similar to that of rat.

[Histological study of the visceral organs of Mongolian gerbil Meriones unguiculatus as a subject in spaceflight experiments].

Survey histological study of the heart, lung, liver, kidney, pancreas, adrenals, thymus, spleen, testicles of the Mongolian gerbil Meriones unguiculatus with a body mass of about 27 g showed their macro- and microscopic similarity with the organs of laboratory rats and mice notwithstanding some slight differences. For instance, the ascending knee of Hengle's loop in the gerbil kidney is much better developed and forms in whole a kind of a singular cortical fiber bordering the medulla. It is the well-developed parts of Hengle's ascending loop in gerbil that ensures a more complete water reabsorption decrease the quantity of urine and sharply reduce the amount of exogenous fluid vitally important for animals in arid areas.

[Role of insufficient hormone production in development of osteopenia in consequence of physical loads defficiency].

Experiments with rats deprived of support loading on hind limbs by tail-suspension showed that injection of hormones participating in bone metabolism impeded the development of tibial spongy osteopenia; also, normalization of longitudinal bone growth was observed in several cases. Investigations were aimed to evaluate the effectiveness of growth hormone, sex hormones, thyreoid hormones, calcitonin, CNS stimulating ephedrine and strychnine, and graded support loads. The best results were obtained after injection of calcitonin combined with sinestrol (synthetic analog of estradiol) and graded support loads which acted as initiators and amplifiers of hormonal effects.

[Action of estradiol, calcitonin and weight-loading on the development of osteopenia in tail-suspended female rats].

Experiments with tail-suspended female rats demonstrated that injection of sinestrol (synthesized estradiol) and myocalcic (sermon calcitonin) on a background of graded weight bearing (suspension interruption for 2 hrs. a day) prevented osteopenia in the spongy metaphyses of the shin-bone deprived of loading.

[Dynamics of the structural recovery of the rat's tibia from suspension-produced osteopenia].

The qualitative histomorphometric techniques were used to study the dynamics of tibia structural recovery from osteopenia in 30 female rats previously suspended by tail for 30 days. The suspension was found to have caused osteopenia in the tibial proximal metaphysis that was fully gone only after 60 day; in other words, readaptation took twice as much time as the osteopenia development. This fact should be taken into consideration by designers of rehabilitative methods.