The plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are native species unique to the Qinghai-Tibetan Plateau with successful adaptation to the hypoxic environment. In this study, the number of red blood cells, hemoglobin concentration, mean hematocrit and mean volume of red blood cells were measured in plateau zokors and plateau pikas at different altitudes. Hemoglobin subtypes of two plateau animals were identified by mass spectrometry sequencing. The forward selection sites in two animals' hemoglobin subunits were analyzed by PAML4.8 program. Homologous modeling was used to analyze the effect of forward selection sites on the affinity of hemoglobin to oxygen. The adapting strategies of plateau zokors and plateau pikas to hypoxia at different altitudes were analyzed through comparing blood parameters between the two species. The results indicated that, with increasing altitudes, plateau zokors responded to hypoxia by increasing red blood cell count and decreasing red blood cell volume, while plateau pikas took the opposite strategies to plateau zokors. In erythrocytes of plateau pikas, both adult α₂β₂ and fetal α₂ε₂ hemoglobins were identified, while erythrocytes of plateau zokors only had adult α₂β₂ hemoglobin, however the affinities and the allosteric effects of the hemoglobin of plateau zokors were significantly higher than those of plateau pikas. Mechanistically, in the α and β subunits of hemoglobin of plateau zokors and pikas, the numbers and the sites of the positively selected amino acids as well as the side chain groups polarities and orientations of the amino acids differed significantly, which may result in the difference of the affinities to oxygen of hemoglobin between plateau zokors and pikas. In conclusion, the adaptive mechanisms to respond to hypoxia in blood properties of plateau zokors and plateau pikas are species-specific.
Animals ; Altitude ; Amino Acids ; Hemoglobins ; Hypoxia ; Lagomorpha

In the present study, the composition and content of pulmonary surfactant (PS) were analyzed to explore the hypoxia adaptation mechanism in plateau zokors (Myospalax baileyi) and plateau pikas (Ochotona curzoniae). 36 plateau zokors and plateau pikas were trapped alive at the Laji Mountain in Guide County, Qinghai Province (at the altitude of about 3 600 m), and 36 Sprague-Dawley (SD) rats were purchased from the experimental animal center of Lanzhou University (at the altitude of about 1 500 m). All animals were lavaged after laboratory anesthesia, the blood in lung tissues was fully washed out and the lung tissues were then taken out to obtain the bronchoalveolar lavage fluid by bronchoalveolar lavage. The composition and content of phospholipids in the PS of three different kinds of animals were analyzed by using high performance liquid chromatography; the protein composition, content and types in the PS were analyzed by G-250 Coomassie brilliant blue method, polyacrylamide gel electrophoresis (PAGE) and mass spectrometry; the dissolved oxygen in the PS solutions were determined by using dissolved oxygen electrode. The results showed that the total contents of phospholipids in the PS were successively increased among plateau zokors, plateau pikas and SD rats (P < 0.05), while the total content of proteins successively decreased (P < 0.05). There were five phospholipids identified in the PS, including linoleic palmitoylphosphatidylcholine (LPPC), dipalmitoylphosphatidylcholine (DPPC), phosphatidylglyerol (PG), phosphatidylinositol (PI) and phosphatidylserine (PSe), but the relative contents of these phospholipids were different. The relative content of LPPC was successively increased among plateau zokors, plateau pikas and SD rats (P < 0.01). The relative contents of DPPC, PG and PI in the PS of plateau zokors were significantly higher than those of plateau pikas (P < 0.01), while insignificant differences between plateau pikas and SD rats (P > 0.05). The relative content of PSe had no significant differences between plateau zokors and plateau pikas (P > 0.05), but both were significantly higher than that of SD rats (P < 0.01). The serum albumin (SA) was identified in the PS of three kinds of animals, including homologous tetramer protein containing heme, which is composed of hemoglobin β subunit, in plateau zokors and plateau pikas. Immunoglobulin (Ig) heavy chain was found in PS of plateau zokors and SD rats. The content of Ig heavy chain in plateau zokor was significantly higher than that in SD rats (P < 0.01), and the content of protein containing heme was significantly higher than that in plateau pikas (P < 0.05). The amount of dissolved oxygen was successively decreased in the PS among plateau zokors, plateau pikas and SD rats (P < 0.01), but it was significantly higher than that in saline (P < 0.01). These results suggest that the total content of proteins in the PS of plateau zokors and plateau pikas was significantly higher, while the total content of phospholipids was significantly decreased. There were high content of homologous tetramer protein containing heme in the PS of plateau zokors and plateau pikas. The relative content of DPPC, the main component of phospholipids, was significantly increased in plateau zokors. The changes of PS component and content improve the adaptability of the two plateau animals in hypoxia environment.
Altitude ; Animals ; Hypoxia ; Lagomorpha ; Pulmonary Surfactants ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the intergrating of N-isopropyl oxamate and serum protein and establish a high performance liquid chromatography (HPLC) detection method of N-isopropyl oxamate (specific inhibitor of testis-specific lactate dehydrogenase (LDH-C4)) in the blood of plateau pikas.

METHODSTwenty highland pika 150-200 g, were randomly divided into two groups (n = 10): control group and inhibitor group. Different concentrations of N-isopropyl oxamate were added to examine the intergrating of N-isopropyl oxamate and serum protein. In order to determine its concentration in the pika blood accurately, we used the method of adding trypsin to incubate the serum first, followed by trichloroacetic acid treatment and detecting by HPLC. Results: When the concentrations of N-isopropyl oxamate in the pika serum were added to 0.05 mmol/L, 0.1 mmol/L, 1 mmol/L, 10 mmol/L, 16.7 mmol/L, 33.3 mmol/L and 100 mmol/L, the intergrating rates between N-isopropyl oxamate and plateau pika serum were 100%, 100%, 100%, 86.84%, 54.11%, 40.10% and 20.18%, respectively. The method established in this paper was good on recovery rates, precision and stability. A good linearity was obtained in the range of 0.0125-0.25 mmol/L. When the concentrations of N-isopropyl oxamate in the serum were added to 0. 15 mmol/L,0.3 mmol/L and 1 mmol/L, the recovery rates were 98.05%, 98.98% and 98.12%, respectively; the precision relative standard deviation( RSD) of concentrations were 1.17%, 0.92% and 0.83%, respectively; the stability relative standard deviation (RSD) of concentrations were 1.38%, 1.40% and 0.88%, respectively. The repeatability RSD of the method was 1.76%. Quantitative limit was 0.0125 mmol/L.

CONCLUSIONN-isopropyl oxamate has a strong affinity with plateau pika serum protein that can't be accurately determined with common HIPLC method. It can be accurately determined in the blood by adding trypsinto digest the serum protein first, followed by adding trichloroacetic acid to precipitate the protein.

Animals ; Chromatography, High Pressure Liquid ; methods ; Lagomorpha ; Male ; Oxamic Acid ; analogs & derivatives ; blood

The aim of the present study was to observe the effects of hypoxia on tensions of aortic rings of pika (Ochotona curzoniae) and Sprague-Dawley (SD) rat. The aortic rings were prepared, and in vitro vascular ring perfusion was used to assay the effects of hypoxia or different drugs on contraction responses of the rings with or without endothelium. The results showed that, there was no difference of the contractions to KCl (80 mmol/L) between the aortic rings of the pikas and SD rats. After pre-contraction with NE (1 μmol/L), the aortic rings with endothelium of the SD rats showed obvious relaxation to ACh (1 μmol/L), whereas the aortic rings of the pikas, no matter with or without endothelium, showed significant and unusual contraction to ACh. The aortic rings of pikas, no matter with or without endothelium, exhibited greater contraction when treated by 1 h of hypoxia, compared with those in SD rats; The similar result was showed under hypoxia in combination with Ca(2+) removal. These results suggest that the contraction response to hypoxia in pika is more sensitive compared to that in SD rat, which is dependent on the release of calcium from intracellular calcium store.
Animals ; Aorta, Thoracic ; physiology ; Arterial Pressure ; Calcium ; physiology ; Hypoxia ; In Vitro Techniques ; Lagomorpha ; Rats ; Rats, Sprague-Dawley

BACKGROUNDThe rodentia and lagomorpha animals are the intermediate hosts of Echinococcus multilocularis, their distribution and infection of this parasite may facilitate the infection of definitive hosts such as dogs. The aim of this study was to determine the distribution of the intermediate hosts of Echinococcus multilocularis in Shiqu County, Sichuan, China.

METHODSA systematic sampling method was used to investigate the density of burrows of rodents and lagomorphs at 97 pasture sites in winter and summer pastureland and remote sensing (RS) technology was used to correlate their densities to the distribution of these animals in different landscape types.

RESULTSBased on the densities of Ochotona curzoniae, Microtus fuscus (dependent variable) and their burrow densities (independent variable) in survey points, regression equations were fitted respectively (Ochotona curzoniae, P < 0.0001, R(2) = 0.8705; Microtus fuscus, P < 0.0001, R(2) = 0.9736). Their burrow density in summer pastureland was higher than in winter pastureland (F = 36.65, P < 0.0001). The burrow densities of Ochotona curzoniae and Microtus fuscus in bareland and half-bareland are higher than in grassland (F = 7.73, P < 0.001).

CONCLUSIONSThe regression relationship between the densities of Ochotona curzoniae and Microtus fuscus and their burrow densities indicate that the burrow densities could reflect the animal densities and that the burrow density was greater in summer pastureland than in winter pastureland. The main distribution areas of the intermediate hosts were in bareland and half-bareland.

Animals ; Arvicolinae ; parasitology ; China ; Echinococcosis ; epidemiology ; transmission ; Echinococcus multilocularis ; pathogenicity ; Lagomorpha ; parasitology

Bartonella species can infect a variety of mammalian hosts and cause a broad spectrum of diseases in humans, but there have been no reports of Bartonella infection in Ochotonidae. This is the first study to detect Bartonella in plateau pikas in the Qinghai plateau, providing baseline data for the risk assessment of human Bartonella infection in this area. We obtained 15 Bartonella strains from 79 pikas in Binggou and Maixiu areas of Qinghai with a positive rate of 18.99%. Based on the phylogenetic analysis of the Bartonella citrate synthase (gltA) gene sequences, most strains were closely related to B. taylorii (3/15) and B. grahamii (12/15). The latter is a pathogenic strain in humans. Our results suggest that a corresponding prevention and control strategy should be taken into consideration in the Qinghai province.
Animals ; Bartonella ; classification ; genetics ; isolation & purification ; Bartonella Infections ; epidemiology ; microbiology ; transmission ; veterinary ; China ; epidemiology ; Female ; Genotype ; Humans ; Lagomorpha ; Male ; Phylogeny

Plateau zokor (Myospalax baileyi) is a subterranean mammal. Plateau zokor has high learning and memory ability, and can determine the location of blocking obstacles in their tunnels. Forkhead box p2 (FOXP2) is a transcription factor implicated in the neural control of orofacial coordination and sensory-motor integration, particularly with respect to learning, memory and vocalization. To explore the association of foxP2 with the high learning and memory ability of plateau zokor, the cDNA of foxP2 of plateau zokor was sequenced; by using plateau pika as control, the expression levels of foxP2 mRNA and FOXP2 protein in brain of plateau zokor were determined by real-time PCR and Western blot, respectively; and the location of FOXP2 protein in the brain of plateau zokor was determined by immunohistochemistry. The result showed that the cDNA sequence of plateau zokor foxP2 was similar to that of other mammals and the amino acid sequences showed a relatively high degree of conservation, with the exception of two particular amino acid substitutions [a Gln (Q)-to-His (H) change at position 231 and a Ser (S)-to-Ile (I) change at position 235]. Higher expression levels of foxP2 mRNA (3-fold higher) and FOXP2 protein (>2-fold higher) were detected in plateau zokor brain relative to plateau pika brain. In plateau zokor brain, FOXP2 protein was highly expressed in the cerebral cortex, thalamus and the striatum (a basal ganglia brain region). The results suggest that the high learning and memory ability of plateau zokor is related to the high expression levels of foxP2 in the brain.
Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Brain ; metabolism ; Forkhead Transcription Factors ; metabolism ; Lagomorpha ; physiology ; Learning ; Memory ; RNA, Messenger

Plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzniae) are native to the Qinghai-Tibet plateau. To study their adaptive mechanisms, the ratios of heart weight to body weight (HW/BW) and right to left ventricular plus septum weights [RV/(LV+S)] were determined; the microvessel density (MVD) of cardiac muscle were measured by immunohistochemical staining; the numerical density on area (N(A)), volume density (V(V)), specific surface (δ), and surface density (S(V)) of mitochondria were obtained by microscopy and stereology; the contents of myoglobin (Mb) and lactic acid (LD), and the activity of lactate dehydrogenase (LDH) in cardiac muscle were analyzed by spectrophotometer. The results showed that the HW/BW of plateau zokor [(4.55±0.26)%] and plateau pika [(4.41±0.38)%] was significantly greater than that of Sprague-Dawley (SD) rat [(3.44±0.41)%] (P<0.05), but the RV/(LV+S) [(22.04±1.98)%, (25.53±3.41)%] was smaller than that of SD rats [(44.23±3.87)%] (P<0.05). The MVD and N(A) of cardiac muscle were 1688.631±250.253 and 0.768±0.123 in SD rat, 2002.888±367.466 and 0.868±0.159 in plateau pika and 2 990.643±389.888 and 1.012±0.133 in plateau zokor. The V(V) of mitochondria in plateau zokor (0.272±0.045) was significantly lower than that in plateau pika (0.343±0.039) and SD rat (0.321±0.048) (P<0.05), while the δ of mitochondria in plateau zokor (9.409±1.238) was higher than that in plateau pika (6.772±0.892) and SD rat (7.287±1.373) (P<0.05). The S(V) of mitochondria in plateau pika (2.322±0.347) was not obviously different from that in plateau zokor (2.468±0.380) and SD rat (2.227±0.377), but that in plateau zokor was significantly higher than that in SD rat (P<0.05). The contents of Mb in cardiac muscle of plateau zokor [(763.33±88.73) nmol/g] and plateau pika [(765.96±28.47) nmol/g] were significantly higher than that of SD rat [(492.38±72.14) nmol/g] (P<0.05), the content of LD in plateau zokor [(0.57±0.06) mmol/L] was obviously higher than that in plateau pika [(0.45±0.06) mmol/L] and SD rat [(0.48±0.02) mmol/L] (P<0.05), and the activity of LDH in plateau zokor [(16.90±2.00) U/mL] and plateau pika [(20.55±2.46) U/mL] were significantly lower than that in SD rat [(38.26±6.78) U/mL] (P<0.05). The percentage of LDH-H in cardiac muscle decreased in order in plateau zokor, plateau pika and SD rat. In conclusion, plateau zokor and plateau pika adapt better to hypoxia than SD rat by increasing the SV of mitochondria, MVD and content of Mb in the cardiac muscle. However, the parameters of mitochondria in the two high-altitude animals are different possibly because of the differences of habitats and habits.
Adaptation, Physiological ; Animals ; Heart ; physiology ; Hypoxia ; metabolism ; Isoenzymes ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Lagomorpha ; physiology ; Rats ; Rats, Sprague-Dawley ; Tibet

AIMTo investigate the role of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) on pulmonary vascular structural remodeling in rats and pika.

METHODSThe Wistar rats which reside at 2 260 m were carried to 3 417 m. After they were fed 24 hours,2 weeks and 3 weeks respectively, the level of VEGF and ET-1 were measured using a kit by ELISA method. Pulmonary tissue was taken out to stain with elastica-Van Gieson. The amount of pulmonary arteries (< 100 microm) and the component ratio of MA, PMA,and NMA were calculated by using a light microscope. The ratio of right ventricle weight to left ventricle plus septum weight (RV/LV + S) were measured.

RESULTSThe ET-1 was significantly different in pika as compared with 24 h, 2 weeks, 3 weeks hypoxic rats (P < 0.01) respectively. The levels of VEGF in 2 weeks, 3 weeks rats were much higher than that of pika but no difference was found between pika and 24 h hypoxic rats. The ratio of MA, PMA obviously increased, and NMA decreased significantly, right ventricular hypertrophy was developed in differ groups of hypoxic rats.

CONCLUSIONThe VEGF and ET-1 participate the muscularization of pulmonary vessels during hypoxia and play an important role in the process of hypoxic pulmonary hypertension in rats, however the VEGF and ET-1 may be maintainable only normal organic function in pika.

Animals ; Endothelin-1 ; metabolism ; Female ; Hypertension, Pulmonary ; metabolism ; Hypoxia ; metabolism ; Lagomorpha ; Lung ; blood supply ; Male ; Pulmonary Artery ; metabolism ; Rats ; Rats, Wistar ; Vascular Endothelial Growth Factor A ; metabolism

The plateau pika (Ochotona curzoniae) has a strong adaptability to hypoxic plateau environment. We found that the sperm-specific lactate dehydrogenase (LDH-C4) gene Ldh-c expressed in plateau pika cardiac muscle. In order to shed light on the effect of LDH-C4 on the anaerobic glycolysis in plateau pika cardiac muscle, 20 pikas were randomly divided into the inhibitor group and the control group, and the sample size of each group was 10. The pikas of inhibitor group were injected with 1 mL 1 mol/L N-isopropyl oxamate, a specific LDH-C4 inhibitor, in biceps femoris muscle of hind legs, each leg with 500 μL. The pikas of control group were injected with the same volume of normal saline (0.9% NaCl). The mRNA and protein expression levels of Ldh-c gene in plateau pika cardiac muscle were determined by real-time PCR and Western blot. The activities of LDH, and the contents of lactate (LD) and ATP in cardiac muscle were compared between the inhibitor group and the control group. The results showed that 1) the expression levels of Ldh-c mRNA and protein were 0.47 ± 0.06 and 0.68 ± 0.08, respectively; 2) 30 min after injection of 1 mL 1 mol/L N-isopropyl oxamate in biceps femoris muscle, the concentration of N-isopropyl oxamate in blood was 0.08 mmol/L; 3) in cardiac muscle of the inhibitor group and the control group, the LDH activities were (6.18 ± 0.48) U/mg and (9.08 ± 0.58) U/mg, the contents of LD were (0.21 ± 0.03) mmol/g and (0.26 ± 0.04) mmol/g, and the contents of ATP were (4.40 ± 0.69) nmol/mg and (6.18 ± 0.73) nmol/mg (P < 0.01); 5) the inhibition rates of N-isopropyl oxamate to LDH, LD and ATP were 31.98%, 20.90% and 28.70%, respectively. The results suggest that Ldh-c expresses in cardiac muscle of plateau pika, and the pika cardiac muscle may get at least 28% ATP for its activities by LDH-C4 catalyzed anaerobic glycolysis, which reduces the dependence on oxygen and enhances the adaptation to the hypoxic environments.
Acclimatization ; Animals ; Glycolysis ; Hypoxia ; Isoenzymes ; genetics ; metabolism ; L-Lactate Dehydrogenase ; genetics ; metabolism ; Lactic Acid ; analysis ; Lagomorpha ; genetics ; Male ; Myocardium ; enzymology ; Oxamic Acid ; analogs & derivatives ; Oxygen ; RNA, Messenger