STUDIES OF SPACEFLIGHT EFFECTS ON A 3D MODEL OF CHONDROBLAST CULTURE.

The effect of long-duration space flight on the vital processes in human chondroblasts in vitro was studied with a number of morphologic, biochemical and optic techniques. Object of investigation was a 3-D porous biocarrier populated by a cell culture in a leak-free vessel completely full of growth medium. The investigation was performed onboard automatic .spacecraft Foton-M4 with the use of research equipment SIGMA. Synchronous experiments were conducted in ground laboratory. The experiment with cell culture prepared of the human hyaline cartilage validated suitability of this model for long-duration experiments with adhesive cells on automatic spacecraft; besides, the experimental results suggest that in spaceflight microgravity adhesive cells exist in the state of suspension.

[The effect of insulin on circadian rhythm of voluntary locomotor activity in rats].

Effects of single intranasal administration of 0.2 ng insulin at different moments of the projected daily cycle (ZT = 1, ZT = 7, ZT = 13 and ZT = 19) on the circadian rhythms of voluntary locomotor activity (wheel-running) were studied in Wistar male rats. Insulin administered at ZT-7 or ZT-13 induced a statistically significant phase advance by 4.4 and 5.5 hours, respectively. The administration of insulin at ZT-13 additionally induced a reduction of the period of the circadian rhythm of voluntary locomotor activity. Intranasal administration of insulin at other moments of the projected daily cycle (ZT = 1 or ZT = 19) did not induce any statistically significant change in phase or period duration of the circadian rhythms. Insulin did not cause changes in total daily activity irrespective of administration time. The results of the study suggest the role of endogenous insulin as entrainment factor for circadian oscillator in absence of the main physiological zeitgeber--cyclic afferent input from retina photoreceptors.