Perinatal expression of heat-shock protein 90 in different regions of the brain and in non-neural tissues of the piglet

Comparative analysis of αB-crystallin expression in heat-stressed myocardial cells in vivo and in vitro

Relationships between αB-crystallin expression patterns and pathological changes of myocardial cells after heat stress were examined in vitro and in vivo in this study using the H₉C₂ cell line and Sprague-Dawley rats, respectively. Histopathological lesions, characterized by acute degeneration, karyopyknosis and loss of a defined nucleus, became more severe in rat hearts over the course of heat stress treatment from 20 min to 100 min. The expression of αB-crystallin in rat hearts showed a significant decrease (P<0.05) throughout the heat stress treatment period, except at the 40 min time point. Likewise, decreased αB-crystallin expression was also observed in the H₉C₂ cell line exposed to a high temperature in vitro, although its expression recovered to normal levels at later time points (80 and 100 min) and the cellular damage was less severe. The results suggest that αB-crystallin is mobilized early after exposure to a high temperature to interact with damaged proteins but that the myocardial cells cannot produce sufficient αB-crystallin for protection against heat stress. Lower αB-crystallin expression levels were accompanied by obvious cell/tissue damage, suggesting that the abundance of this protein is associated with protective effects in myocardial cells in vitro and in vivo. Thus, αB-crystallin is a potential biomarker of heat stress.

Expression and distribution of heat shock proteins in the heart of transported pigs

The expression and localization of four heat shock proteins (Hsp70, Hsp86, Hsp90, and Hsp27) were shown in the heart tissue of pigs transported for 6 h. Immunostaining detected the consistent presence of all Hsps in the pig myocardial cells under both transported and normal housing conditions. Immunohistochemical analysis revealed predominance of Hsp70 (significantly highest levels) and Hsp27 in the cytoplasm of myocardial cells. Hsp90 and Hsp86 were expressed both in the cytoplasm and in the nucleus, preferentially in the cytoplasm, of the myocardial cells. In view of their abundant and uniform distributions in the myocardial cells, the expression and distribution patterns of all detected Hsps within the myocardial cells, mostly limited to the cytoplasm, could be related to their chaperone function for cells with important special activities in this study. The identification of all four Hsps in the blood vessel endothelial cells possibly implies that endothelial cells react to ischemia and hypoxia by expressing Hsps. Immunoblot findings suggest that the level of all Hsps decreased in response to stress due to a 6 h journey. The decrease in Hsp levels in the myocardial cells may indicate that the transport stress may have overcharged the repair mechanisms of the cells. Whether this distinct depletion of Hsps contributes to an increased susceptibility to acute heart failure and the sudden death syndrome in transported pigs should be elucidated in future experiments.

The postnatal development of cerebellar Purkinje cells in the Göttingen minipig estimated with a new stereological sampling technique--the vertical bar fractionator

The postnatal development of total number and perikaryon volume of cerebellar Purkinje cells was estimated in the Göttingen minipig cerebellar cortex using a new stereological approach, the vertical bar fractionator. Data were obtained from the brains of five neonate and five adult female Göttingen minipigs. The total number of Purkinje cells ranged from 1.83 x 10(6) in the neonate to 2.82 x 10(6) in the adult Göttingen minipig. The number-weighted mean perikaryon volume of Purkinje cells increased concurrently from around 6,800 microm(3) in the neonate to 17,600 microm(3) in the adult. The study demonstrates that a pronounced postnatal neurogenesis in Purkinje cell number and perikaryon volume is part of the growth and development of the cerebellum in the Göttingen minipig. The Purkinje cells of the Göttingen minipig were found to be substantially large compared with human and represents the largest cells described hitherto from mammalian cerebella. The vertical fractionator is a new sampling technique, which allows the combination of a fractionator design on vertical bar sections excluding exhaustive sampling and bias from artificial edges. By design, the sections are perfect stereological vertical sections and provide the basis for unbiased estimates of total number of structural entities in the brain, including surface area, fibre length and particle volume.

Effects of hypoxia on stress proteins in the piglet brain at birth

Newborn piglets were submitted to normobaric hypoxia (5% O2, 95% N2) for either 1 or 4 h. The effects of hypoxia on the neonatal brain were characterized through a time-course analysis of levels of various proteins such as heat shock proteins (HSP27, 70, and 90), hypoxia inducible factor-1alpha (HIF-1alpha), neuronal nitric oxide synthase (nNOS), hemeoxygenase-2 (HO-2), and caspase-3. The expression of these proteins was determined at different stages of recovery up to 72 h in cerebellum, cortex, and hippocampus by Western blot analysis in hypoxic maintained animals that were made hypoxic at either 20 or 37 degrees C. In all regions of the brain, HIF-1alpha and HSP27 expression were strongly increased until 22 h of recovery. No significant changes were observed for HSP70, HSP90, and HO-2. A small elevation of expression of nNOS was observed at early stages in the cerebellum and the cortex with no change in the hippocampus. Expression of caspase 3 was strongly increased in the cortex 24 and 48 h after hypoxia but unchanged in the hippocampus. These results are presented in terms of the porcine model of nonischemic hypoxia and its delayed neuronal effects on the cerebral outcome. Because of their recently established biochemical and functional interactions, the expression of the main HSPs, HIF-1alpha, nNOS, and caspase-3 after hypoxia are delineated.

Expression of small heat shock proteins HspB2, HspB8, Hsp20 and cvHsp in different tissues of the perinatal developing pig

Recently, we have described the developmental expression of the small heat shock proteins (sHsps) Hsp27/HspB1 and alphaB-crystallin/HspB5 in different tissues of pigs from almost full-term foetuses to three years old adults (P. Tallot, J. F. Grongnet, J. C. David, Biol. Neonate, 83, 281-288, 2003). The data described in this report extends this study to four other members of the sHsp family (Hsp20/HspB6, cvHsp/HspB7, MKBP/HspB2 and HspB8). We studied expression of these proteins in porcine lens, brain, heart, liver, kidney, lung, skeletal muscle, stomach, and colon, and found a ubiquitous expression of Hsp20 and HspB8 as earlier reported for Hsp27 and alphaB-crystallin. In contrast, cvHsp and HspB2 expression is essentially restricted to heart and muscle. During development, the sHsps tend to (temporarily) increase in stomach, liver, lung, kidney, hippocampus, and striatum, while expression in heart is more or less constant, and a large variation is found in sHsp expression patterns in skeletal muscle. In cerebellum and cortex a temporary decrease of Hsp20 and HspB8 is observed directly after birth. The major impact of this study is that each tissue seems to have a unique profile of sHsp expression, which varies during development and may reflect the need of a particular tissue to maintain at all stages an optimal chaperoning machinery to protect against physiological stress.

Dual perinatal and developmental expression of the small heat shock proteins [FC12]aB-crystallin and Hsp27 in different tissues of the developing piglet

Expression of the two closely related heat shock proteins (HSPs), alpha B-crystallin and Hsp27, was studied in various tissues of the developing pig. Expression of alpha B-crystallin was maximum in the lens while expression of Hsp27 was absent. In non-lenticular tissues, both proteins were strongly expressed in heart and muscle. Increases in alpha B-crystallin expression were observed in brain, liver and kidney while Hsp27 was increased in kidney at later stages. Relatively constant expression was found in heart while a decrease in both stress proteins was observed between 28 days and 6 months in skeletal muscle. In the different parts of the gastrointestinal tract, increased expression of alpha B-crystallin was seen following birth and weaning while increased expression of Hsp27 was restricted to weaning. These results are discussed in terms of the protective effects of HSPs during stressful events in the different tissues of the developing pig.

Weaning affects the expression of heat shock proteins in different regions of the gastrointestinal tract of piglets

Heat shock proteins (HSP) play a central role in the protection of cells, tissues or organs subjected to various types of stressors. Different nutrients have been recently shown to exert their protection through the induction of HSP. Because these nutrients alleviate alterations of the intestine after weaning in pigs, this study was designed to obtain basic information on the expression of HSP 27, heat shock cognate 70 (HSC 70), HSP 70 and HSP 90 along the gastrointestinal tract (GIT) of young pigs and to study the effect of weaning on this expression. Pigs were weaned at 28 or 21 d and slaughtered at various times postweaning. All HSP were expressed in the GIT segments studied before and after weaning. However, the expression of HSP 27 and HSP 70 was transiently increased in the stomach and duodenum between 6 and 12 h postweaning and between 24 and 48 h in the mid-jejunum, ileum and colon. Their expressions were transiently decreased in the ileum. Expression of HSP 90 increased in the stomach and jejunum but decreased in the duodenum, ileum and colon. Similar results were obtained at both ages of weaning. We conclude that the HSP studied are present all along the gut of pigs and that their expression is modulated through weaning according to spatial-temporal patterns. The modulation by nutrients of HSP and their protective role on the GIT remain to be investigated in pigs.