Temporal regulation of extracellular signal-regulated kinase 1/2 phosphorylation, heat shock protein 70 and activating transcription factor 3 during prostaglandin F-induced luteal regression in pseudopregnant rats following heat stress.

The aim of the present study was to investigate the effects of heat stress on heat shock protein (HSP) 70 expression and mitogen-activated protein kinase (MAPK) and protein kinase (PK) B signalling during prostaglandin F (PGF)-induced luteal regression. During pseudopregnancy, rats were exposed to heat stress (HS, 40°C, 2h) for 7 days and treated with PGF or physiological saline on Day 7; serum and ovaries were collected 0, 1, 2, 8 or 24h after PGF treatment. The early inhibitory effect of PGF on progesterone was reduced in HS rats. HSP70 expression in response to PGF was significantly enhanced in HS rats. PGF-induced phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was significantly greater in the HS group; however, HS rats exhibited elevated basal levels of phosphorylation of p38 MAPK, but not ERK1/2. PGF treatment increased expression of activating transcription factor (ATF) 3 at 2h, which was inhibited by heat stress. Evaluating PKB signalling revealed that phosphorylation of p-Akt (Thr308 and Ser473) was reduced at 8 and 24h after PGF treatment in both non-heat stress (NHS) and HS groups, but there were no significant differences between the HS and NHS groups at any of the time points. In conclusion, the present study provides further evidence that heat stress may enhance HSP70 and affect ERK1/2 and ATF3 expression, but not Akt activation, during PGF-induced luteal regression in pseudopregnant rats.

Effects of Daily Exposure to Saccharin and Sucrose on Testicular Biologic Functions in Mice.

Saccharin sodium consumption is considered safe and beneficial, owing to its very intense sweetness without any associated calories, but supporting scientific data remain sparse and controversial. Herein, we demonstrate that dose-response relationships existed with regard to administration of saccharin or sucrose to mice for 35 days, and this association involved testis-expressed sweet-tasting molecules (taste receptor type 1 subunit 3 [T1R3]; G protein alpha-gustducin [Galpha]). Mouse body weights and testis weights in middle- and low-dose saccharin-treated groups were increased with up-expressions of molecules involved in testicular sweet taste and steroidogenic (middle saccharin: steroidogenic acute regulatory protein [StAR]; P450 cholesterol side-chain cleavage enzyme [CYP11A1]; 17-alpha-hydroxylase/C17,20-lyase [CYP17A1]; low saccharin: StAR). Moreover, a high-dose saccharin-related decline in reproductive hormone levels and injuries to testis and sperm were observed to be associated with suppression of testicular T1R3 and Galpha, as well as steroidogenic-related factors (StAR; 3-beta-hydroxysteroid dehydrogenase [3-beta-HSD]; CYP11A1; CYP17A1; 17-beta-hydroxysteroid dehydrogenase [17-beta-HSD]), and activation of cleaved caspase-3. However, abnormalities of the testis and sperm in high- and middle-dose sucrose-exposed mice were related to the increased-cleaved caspase-3, but independent of T1R3 and/or Galpha. Collectively, our results clearly suggest that saccharin-induced physiologic effects on testis are associated with testicular T1R3 and Galpha, which differed from sucrose. We hence call for a reassessment of the excessive use of sweeteners in daily life, especially artificial ones, considering their potential side effects.

[Single nuclear polymorphisms in exon 3 of POMC gene and the association with growth traits in Hu sheep and East Friesian x Hu crossbred sheep].

Pro-opiomelancortin (POMC) plays important roles in the regulation of food intake and energy expenditure. The sheep exon 3 of gene POMC was amplified and sequenced by screening the DNA pools to select single nuclear polymorphisms and analyze the association with the growth traits. Two silent SNP mutations (g.273 T/C and g.456 G/A) in Hu sheep were identified. PCR-restriction fragment length polymorphism (RFLP) was used to test the g.273 T/C and the association between the g.273 T/C polymorphism and some growth traits was analyzed in Hu sheep (n = 162) and East Friesian x Hu crossbred sheep (n=130). The results showed that three genotypes, TT, TC and CC, were detected in Hu sheep with the frequencies of 0.469, 0.438 and 0.093, respectively. Two genotypes, TT and TC, were detected in East Friesian x Hu crossbred sheep with the frequencies of 0.754 and 0.246, respectively. The association analysis showed that in Hu sheep the two-month weaning weight, four-month rump height of genotype CC and the four-month body length, cannon circumference of genotype TC were significantly higher than those of genotype TT (P < 0.05); the four- and six-month weight of genotype CC were significantly higher than those of genotypes TT and TC (P < 0.01); the four-month body height and body length of genotype CC were significantly higher than those of genotypes TT (P < 0.01) and TC (P < 0.05); the four-month cannon circumference of CC genotype was significantly higher than that of TT genotype (P < 0.01). In East Friesian x Hu crossbred sheep the two-month weaning weight, four-month weight, body height, body length, chest depth and cannon circumference of genotype TC were significantly higher than those of genotype TT (P < 0.05); the six-month weight of genotype TC was significantly higher than that of genotype CC (P < 0.01). In conclusion, the exon 3 of gene POMC was associated with growth traits, and C allele was beneficial to the increase of body weight and body size traits of sheep, which potentially afford a good foundation for further study on POMC gene as aided breeding markers for growth traits in sheep.

Morphologic observation and classification criteria of atretic follicles in guinea pigs.

There is a lack of appropriate classification criteria for the determination of atretic follicles in guinea pigs. In the present study, new criteria were established based on the latest morphologic criteria for cell death proposed by the Nomenclature Committee on Cell Death (NCCD) in 2009. Ovaries of guinea pigs were sampled on different stages of estrous cycle, and the morphologic observations of atretic follicles were investigated in serial sections. The results showed that the process of follicular atresia could be classified into four continuous stages: (1) the granulosa layer became loose, and some apoptotic bodies began to appear; (2) the granulosa cells were massively eliminated; (3) the theca interna cells differentiated; and (4) the residual follicular cells degenerated. In addition, the examination revealed that these morphologic criteria were accurate and feasible. In conclusion, this study provides new criteria for the classification of atretic follicles in guinea pigs, and this knowledge can inform future research in the area.

Effect of genetic adjuvants on immune respondance, growth and hormone levels in somatostatin DNA vaccination-induced Hu lambs.

The aim of current study was to evaluate the prospects of adjuvants against DNA vaccination (pES/2SS) encoding somatostatin (SS) and hepatitis B surface antigen fusion gene. A total of 60 female Hu lambs were divided into 6 groups and vaccinated in the context of various adjuvants (and controls): pE-CpG, Escherichia coli DH5alpha DNA, crude liposomes or GM-CSF in combination with the pES/2SS plasmid. Controls included pES/2SS only vaccinated and physiological saline groups. The antibody against SS level in the E. coli DH5alpha DNA group was significantly increased compared to that in the pES/2SS vaccine alone. Vaccination with pES/2SS/pE-CpG or pES/2SS/E. coli DH5alpha resulted in elevated weight gains that were 33.0 and 31.6% higher, respectively, than in saline group and pES/2SS only vaccinated controls. The concentrations of GH and IGF-I in the DNA vaccine groups were remarkably higher than those in the saline group, and those with positive antibody higher than negative antibody. These results suggested that different adjuvant/pES/2SS combinations can enhance the immune effect and had significant positive effects on growth.

[Association between the canine monoamine oxidase B (MAOB) gene polymorphisms and behavior of puppies in open-field test].

Excitability, activity and exploration behavior of puppies in a novel open-field were tested in a total of 204 two-month-old German shepherd dog, labrador retriever or English springer spaniel puppies. The polymorphisms of monoamine oxidase B gene (MAOB) were detected by PCR-RFLP. Statistics analysis indicated that genotype and allele frequencies of the polymorphisms were significantly different among three breeds (P < 0.01). With GLM analysis of SAS software, association analysis was conducted between MAOB gene polymorphisms and locomotion and vocalization behavior parameters in the open-field test. The results showed that MAOB gene polymorphisms had a significant effect on walking time, squares crossed, lying time, the times of standing up against walls(P < 0.01 or P < 0.05) and were associated with the times of posture change (P=0.064). Walking time and squares crossed were higher in TT genotype puppies than those in TC and CC puppies (P < 0.05) and the times of posture change and standing up against walls were also higher than those in CC (P < 0.05). In addition, lying time in CC genotype puppies were higher than that in TT (P < 0.05). MAOB had a positive effect on walking time, lying time, squares crossed, the times of posture change, the times of standing up against walls in the three dog breeds that was highly statistically significant (P < 0.01 or P < 0.05). Our results imply that MAOB gene significantly affects the excitability, activity and exploration behavior of puppies in open-field test and TT genotype has favorable effects in these behavior traits.

Polymorphism of FecB gene in nine sheep breeds or strains and its effects on litter size, lamb growth and development.

Nine sheep breeds or strains, including 615 individuals were screened with forced PCR RFLP method for the FecB gene to study the polymorphism and its effects on litter size, body weight and body size. Results showed that the polymorphism frequencies of FecB gene were significantly imbalanced in these breeds or strains. The Hu sheep were all homozygous carriers of FecB gene(BB). In the Chinese Merino prolific meat strain, the genotype frequencies of BB, B+ and ++ were 51%, 30% and 19%, respectively, whereas all the other flocks had only the wild-type (++) genotype. Results within the Chinese Merino prolific meat strain showed that the mean litter size of ewes with genotype BB and B+ were 2.8 (+/-0.74) and 2.3 (+/- 0.63) (P < 0.05), whereas ++ genotype ewes had a litter size of only 1.2 (+/-0.68) (P < 0.01). At day 90 after birth, the body weights of BB/B+ genotype lambs were higher than that of ++ genotype lambs (18.6 +/- 3.70 kg, 18.0 +/- 3.71 kg vs 15.6 +/- 2.22 kg, P < 0.05). In addition, the heart girth and chest width of BB/B+ genotype lambs were significantly longer than those of the ++ lambs (P < 0.05). No significant differences were observed in either body weight or body size at day 120. Litter size at first lambing from Hu at Natural Source Conservative Region was found to be significantly higher than that from the other two regions sampled (P < 0.05). In addition to the additive effect on litter size, these findings showed for the first time that the FecB gene had a positive effect on early postnatal body growth.