Levels of medium-molecular-weight peptides in the cerebral cortex of rats of different ages and nervous system types under high-protein and protein-free diets

The changes of body mass of rats of different age fed on a protein-free diet (PFD) were investigated. An experiment was conducted on 350 male Wistar rats in 14 age groups ranging from 23 to 275 days and an initial individual shrunk body mass ranging from 37 to 470 grams. Each group of 25 rats of the same age was divided randomly into 5 subgroups corresponding to the PFD feeding periods of 3, 6, 9, 12 and 16 days. Before starting and after finishing each feeding period, the rats were fasted for 14 to 20 hours and weighed, thus determining the initial and the final shrunk body mass (SBi and SBf), respectively. SBf was closely correlated with SBi in all age groups (Table 3). SBf was corrected for SBi by linear covariance. Corrected SBf means are presented in Table 4. Logarithms of SBf means from this table were processed by linear regression method against log t (where t = 3, 6, 9, 12 and 16 days on PFD). Coefficients of regression between age groups (k) did not differ significantly and the common bc = -0.062 +/- 0.002 less than 0**. Changes of body mass of rats during 16 days of ad libitum feeding on PFD are described be the equation: Y = Ak X t-0.062 in which: Y = SBf (in grams) and the values of Ak correspond to SBi in age group k. This demonstrates that the changes of shrunk body mass did not significantly depend on the age but SBf was significantly related to SBi, the latter depending on the age of rats. SBf expressed as percentage of SBi (Figure 1) demonstrates that the losses of body mass were greatest during the first 6 days of feeding on PFD; during this period SBf decreased to about 91% and, during the subsequent 10 days, to about 84% of SBi. The results of this experiment suggest that the body mass of rats fed on PFD, for which the nitrogen balance was determined, should be expressed by the body mass actually linked to the endogenous nitrogen metabolism and not by the mean, or by the initial, body mass.

Effect of protein-free diet on activities and subunits of glutathione S-transferase in livers of young and aged female rats

Paradoxical protection of both protein-free and high protein diets against acute ammonium intoxication

Dietary Protein and Amino Acid Levels Alter Threonine Dehydrogenase Activity in Hepatic Mitochondria of Gallus domesticus

Selective reduction of hippocampal dentate frequency potentiation in aged rats with impaired place learning

Метою дослідження було визначення рівня мелатоніну в сироватці крові у щурів різної статі та віку при виразковому ураженні шлунка. Матеріали та методи. Методом спирто-преднізолонового ушкодження моделювали виразкове ураження шлунка та за допомогою імуноферментного аналізу визначали рівні мелатоніну в сироватці крові у щурів різної статі, які були розподілені на групи за віком, а саме — 3, 9, 15 та 20 міс., що відповідає віку людини 14, 29–30, 43–44, 55–56 років відповідно. Результати. Встановлено, що на тлі виразкового ураження шлунка відбувається вірогідне зниження рівня мелатоніну як у самців, так і у самок у всіх вікових групах. Відносно групи контролю у щурів-самців найбільше зниження відбулося у тварин віком 9 та 20 міс. — на 39 та 43 % відповідно (р ≤ 0,05). У самок на тлі виразкового ураження шлунка зниження рівня мелатоніну відносно групи контролю було на 21–23 % (р ≤ 0,05). Обговорення. Отримані результати свідчать, що виразкове ураження шлунка, ймовірно, призводить до пошкодження ентерохромафінних клітин слизової оболонки шлунка, що супроводжується вірогідними зниженнями рівнів мелатоніну у щурів обох статей і всіх вікових груп, та дозволяють припустити, що саме у чоловіків віком 29–30 та 55–56 років виразкове ураження призводить до значного пошкодження екстрапінеальних джерел синтезу мелатоніну та більш тяжкого перебігу виразкової хвороби з розвитком ускладнень. Висновки. Таким чином, виразкове ураження шлунка призводить до зниження рівнів мелатоніну в сироватці крові у щурів різної статі та віку. Найбільше зниження рівнів мелатоніну при експериментальній виразці шлунка відбувається у щурів-самців віком 9 та 20 міс., що відповідає віку людини 29–30 та 55–56 років.

In male rats of different ages, we studied the functional activity of the pineal gland and the gonads during different seasons by determining the levels of melatonin and testosterone in the blood serum. It was found that the highest levels of melatonin observed in male rats in summer and winter, and the lowest - in autumn. The lowest level of melatonin has been established in the group of rats aged 9 months - 127.28+5.11 pmol/l that was 22% lower than the level of melatonin in 3 months old rats (P!0,05), and 20% below the level of melatonin in rats of 15 months old (Ps0,05). The highest level determined in rats aged 3 months (corresponds to the age of man -14 years old), the lowest - in rats 20 months-(corresponds to the age 55-56 years old). At the same time, the low level of melatonin was defined in rats aged 9 months in the autumn (corresponds to the age of man 29-30 years). In the study of testosterone levels in different seasons it was found that the highest level in all age groups presents in autumn, the lowest - in winter. When comparing the levels of testosterone in different age groups, it was determined that the fall of the highest level of testosterone present in the blood of males age 9 months and 15 months, which corresponds to the age of 29-30 and 43-44 of human years. Significant difference between the levels of testosterone in the groups that correspond to the reproductive age - rats of age 3, 9 and 15 months, are present only in the autumn; spring and summer - significant differences between the levels of testosterone absent. The degree of correlation differed in rats of different ages in different seasons: the highest correlation between the levels of melatonin and testosterone was determined in rats aged 9 months in autumn. The correlation coefficients in rats aged 20 months old have been weak - from 0.05 in the spring to 0.17 in autumn that shows the changes in neurohormonal regulation which occur with age.

The role of beta1-adrenoreceptors at visual associative cortex in rats of different age in the impact on autonomous regulation of the heart rate ander low atmospheric pressure was investigated. The aim of the study was to check expediency of application nebivolol to prevent the adverse effects of hypoxic environment, the pressure conditions similar to the third type of weather. Methods. In the experimental group cardiointervalography recorded in the intact condition before hypoxia, after hypoxic exposure, after trepanation of the skull and applying the solution beta1-blocker nebivolol (0.5 mg / kg) through the trepanation hole on the surface of the cerebral cortex (there were separate groups with right-sided and left-sided trepanation in projection of cortical areas Oc2L), with subsequent automatic analysis of data on a personal computer. In the control group a similar procedure of the experiment was carried out excepting hypoxic exposure. Effect of hypoxic atmosphere was created by reducing pressure by 50.76 hPa (0.05 atm) in the Komovsky’s device and hold the anesthetized rat under a glass bell for 1 hour. Results. In juvenile, adult and old intact rats beta1-receptor structures in left and right associative cortical fields Oc2L are included to the neural circuits that provide growth of functional strenuousness in regulation of heart rhythm. After hypoxic exposure beta1-adrenoreceptors in the left field Oc2L are included in other neural circuits, and take part in limiting the functional strenuousness in regulation of heart rhythm. Conclusions. Experimental results about effectiveness of therapeutic doses of beta-1 adrenoblockers especially nebivolol in adult and old age for prevention of unfavorable effects of hypoxic medium that corresponds to the baric conditions of 111type weather are to be verified by the clinical observations

Correlated regulation of the mRNAs encoding secretory trypsin inhibitors and anionic trypsinogen I in the rat pancreas depending on the dietary protein intake

On chymotrypsinogen and trypsinogen biosynthesis by pancreas of rats fed on a starch-rich or a casein-rich diet

In the ontogenesis process, the cerebral cortex undergoes age-related changes. So far as, unlike practically all other systems of mammalian organs, the brain continues to develop and receive new functionality in the postnatal period. Thus with age, there are changes in the bioelectric characteristics of the neocortex. The purpose of the research is to determine the age and sex changes in the bioelectric activity of the cerebral visual cortex of male and female rats of different ages. In the article, we examined changes in absolute (μV2) and normalized (%) indicators of electrical activity of the visual area of rats of different sexes in four age groups: juvenile, young, mature, and presenile age. The research was carried out by the method of registration of bioelectric activity of electrocorticograms (ECoG). Results of multifactorial dispersion analysis of absolute and normalized ECoG indicators of the visual area of the cerebral cortex of rats of all ages showed that there were reliable changes in the frequency-amplitude characteristics of bioelectric activity related to age. At a young age, males have probably lower absolute and normalized power of the delta-rhythm and the normalized beta-like rhythm rate. There was a tendency of decrease in the theta-rhythm. As a result of this redistribution of rhythms a desynchronization of the electrical activity of young males was observed. Mature males have lower absolute power indicators than younger age groups. According to normalized indicators, a synchronization of rhythms of males in the mature age group was observed, which together with values of absolute power can indicate a decrease of the functional activity level of the neocortex and an increase of the influence of endogenous mechanisms on neuronal activity of the visual area of the cerebral cortex. In the presenile age, there was a desynchronization of rhythms. The indicators of an absolute and normalized power of females in the young age group pointed to the synchronization of the bioecoactivity of the neocortex. Among the low-frequency waves, theta-rhythm rhythm dominated in the females of young age. In the mature and presenile age females, there was a probable increase in the percentage of normalized parameters of high-frequency beta waves. The predominance of this rhythm may indicate an increase of cortical tone. The correlation of values of absolute and normalized indicators of bioelectric activity affirmed the desynchronization of the ECoG rhythms of females of mature and presenile age. Sex differences are expressed by a decrease in the absolute power of all ECoG rhythms of the visual area of the cerebral cortex of females relative to males. The age-related changes occurred in a different way in rats of different sex. At a young age, males had desynchronization of rhythms, and females had synchronization, in the mature age it was vice versa. The age changes of the electric activity of the cerebral visual cortex of rats in our opinion may be largely associated with involutional changes of various neurotransmitter and hormonal systems.

A comparison of the excretion of amino acids by normal and wounded rats on a high protein and protein-free diet was made. The nontaurine amino acid nitrogen excretion was found to be the same the control and wounded animals, although the rats on the high protein diet excreted considerably more amino acid nitrogen than did those on the protein-free diet. The wounded animals on the high protein diet had the same total nitrogen output but excreted significantly larger amounts of taurine than did the nonwounded controls. The wounded animals given the protein-free diet excreted the same amount of taurine but produced more total nitrogen than did the control rats. On the basis of the total nitrogen-taurine excretion ratios, data indicate that cystine is conserved by the wounded as compared to the normal animals.

Adenosine 5'-triphosphatase (ATPase) plays a role in the process of energy conversion in the controlled hydrolysis of ATP. The effect of Ca2+ -binding protein on ATPase activity in the brain cytosol of rats of different ages was investigated. ATPase activity in the brain cytosol of 50-week-old rats was significantly decreased as compared with that of 5-week-old rats. The presence of calcium chloride (10(-5) and 10(-4) M) in the enzyme reaction mixture caused a significant increase in ATPase activity in the brain cytosol of rats of different ages. This increase was not altered by trifluoperazine (2x10(-5) M), an antagonist of calmodulin. Calmodulin (5 microg/ml), calbindin (5 microg/ml) or S-100A protein (10 microg/ml), a Ca2+ -binding protein, had no effect on ATPase activity. Meanwhile, regucalcin (10(-9) M), which is present in brain, significantly decreased ATPase activity in young and older rats. However, the effect of regucalcin was weakened by the presence of Ca2+ (10(-5) M). The addition of anti-regucalcin monoclonal antibody in the reaction mixture caused a significant elevation of ATPase activity; this increase was completely abolished by addition of regucalcin (10(-9) M). The present study suggests that regucalcin plays an inhibitory role in the regulation of ATPase activity in the brain cytosol of rats of different ages.

Introduction This study attempted to explore the mechanism of wound healing in rats of different ages using an reliable and reproducible burn model. Methods A self-made metal column, heated in a boiling water bath, was applied for different time periods to the lower back of rats of different ages in burn creation. Wounds were observed visibly at different time points post burning. Biopsies were obtained and examined at 72 h post burn to determine the depth of burns. In exploring the mechanism of wound healing in rats of different ages, we used primary antibodies including Anti-EGFR [EP38Y] (ab52894) and p75NTR (D4B3) for immunofluorescence of the skin paraffin sections (5μm) obtained from normal rats and on day 3 post burn creation. And we measured the expression of CD271 and EGFR. Results The contact durations producing the desired depth of injury in the rat model under constant temperature and pressure were: 3 seconds (deep second degree) and 5 seconds (third degree) in 1-month-old rats; 3 seconds (superficial second degree), 5 seconds (deep second degree), and 7–9 seconds (third degree) in 2-month-old rats; 3–5 seconds (superficial second degree), 7–9 seconds (deep second degree), and 11–13 seconds (third degree) in 12- and 18-month-old rats. The distribution of CD271 and epidermal stem cells showed no age-related changes (P＞0.05), and the expression of EGFR decreased with age in normal rats (P＜0.001). Compared with normal rats, the content of CD271 and epidermal stem cells and the expression of EGFR increased in burned rats. Conclusions The reliable and reproducible experimental model produces consistent burn injuries in rats of different ages. The number of CD271 and epidermal cells and the expression of EGFR increase during wound healing in rats, suggesting that CD271, epidermal cells and EGFR in epidermal stem cell membranes are associated with burn wound healing. Applicability of Research to Practice This research may be used in clinical practice in the future for better wound care.

This article describes a simple and safe model of partial and full thickness burn injury in rats of different ages, which will be essential in our future burn research to explore the age-related mechanism of wound repair and new therapies for burn injuries. A self-made metal column, which was heated in a boiling water bath, was applied for different time periods to the lower back of rats of different ages in burn creation. Wounds were observed visibly at different time points postburn. Biopsies were obtained and examined at 72-hour postburn to determine the depth of burns. The contact durations producing the desired depth of injury in the rat model under constant temperature and pressure were: 3 seconds (deep second degree) and 5 seconds (third degree) in 1-month-old rats; 3 seconds (superficial second degree), 5 seconds (deep second degree), and 7-9 seconds (third degree) in 2-month-old rats; 3-5 seconds (superficial second degree), 7-9 seconds (deep second degree), and 11-13 seconds (third degree) in 12- and 18-month-old rats. This reliable and reproducible experimental model produces consistent burn injuries in rats of different ages by regulating the contact durations, which will help us to understand the underlying pathophysiology of burn injuries and develop novel therapeutic modalities for burn patients of different ages.