Search

Obesity is a public health problem in both developed and developing countries, and the negative effects of obesity on reproductive physiology have been highlighted recently. We evaluated the effects of porcine obesity index, sex hormones, and peptide hormones on litter size in various breeds of minipigs. Blood samples were collected from sedated 8-,10-, and 12-mo-old minipigs to measure preovulatory levels of sex hormones (follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, testosterone, and prolactin) and peptide hormones (insulin-like growth factor, glucagon, cortisol, growth hormone, free thyroxine, free triiodothyronine, insulin, and leptin). We also measured weight, abdominal circumference, neck circumference, and body length and then calculated the porcine obesity index. Data were analyzed by one-way ANOVA, and means were compared by least significance difference testing. Pearson correlation between parameters and litter size was analyzed. Prepregnancy porcine obesity index and litter size were negatively correlated in primiparous minipigs. Litter size was influenced by luteinizing hormone, estradiol, progesterone, testosterone, prolactin, follicle-stimulating hormone, cortisol, insulin-like growth factor 1, growth hormone, free thyroxine, insulin, and leptin. In conclusion, prepregnancy obesity reduces litter size in primiparous minipigs.

In previous studies from other labs it has been well demonstrated that the ectopic expression of c-Myc in mammary epithelial cells can induce epithelial-mesenchymal transition (EMT), whereas in our pilot experiment, epithelial-like morphological changes were unexpectedly observed in c-Myc-expressing pig fibroblasts [i.e., porcine embryonic fibroblasts (PEFs) and porcine dermal fibroblasts (PDFs)] and pig mesenchymal stem cells, suggesting that the same c-Myc gene is entitled to trigger EMT in epithelial cells and mesenchymal-epithelial transition (MET) in fibroblasts. This prompted us to characterize the existence of a MET in c-Myc-expressing PEFs and PDFs at the molecular level. qRT-PCR, immunofluorescence and western blot analysis illustrated that epithelial-like morphological changes were accompanied by the increased expression of epithelial markers [such as cell adhesion proteins (E-cadherin, α-catenin and Bves), tight junction protein occludin and cytokeratins (Krt8 and Krt18)], the reduced expression of mesenchymal markers [vimentin, fibronectin 1 (FN1), snail1, collagen family of proteins (COL1A1, COL5A2) and matrix metalloproteinase (MMP) family (MMP12 and MMP14)] and the decreased cell motility and increased cell adhesion in c-Myc-expressing PEFs and PDFs. Furthermore, the ectopic expression of c-Myc in pig fibroblasts disrupted the stress fiber network, suppressed the formation of filopodia and lamellipodia, and resulted in RhoA/Rock pathway inactivation, which finally participates in epithelial-like morphological conversion. Taken together, these findings demonstrate, for the first time, that the enforced expression of c-Myc in fibroblasts can trigger MET, to which cytoskeleton depolymerization and RhoA/Rock pathway inactivation contribute.

To study the effect of juglone on the ultrastructure of human liver cancer BEL-7402 cells.BEL-7402 cells were incubated in the presence of 12.5 micromol/L juglone for 24 h, and fixed in 2.5% glutaraldehyde for HE staining and Coomassie brilliant blue staining and scanning electron microscopy.Incubation with juglone resulted in obvious changes in the cell morphology and cytoskeletal alterations of the cells. Scanning electron microscopy revealed reduced volume of the cell bodies, dissociation of the cells, curling and malformation of the microvilli on the cell surface with rupture of the intercellular junction and enlargement of the intercellular space. The formation of apoptotic bodies was observed. Transmission electron microscopy showed expansion of the endoplasmic reticula, mitochondrial cristea disintegration, nucleolar fragmentation and formation of the apoptotic bodies after the exposure to juglone for 24 h.Juglone can cause ultrastructural changes of human liver cancer BEL-7402 cells and induce their apoptosis.

To investigate the relationship of hemorheological parameters between Tibet mini-pigs, Beagle dogs and human.Blood samples were collected from adult Tibet mini-pigs, Beagle dogs and human to detect such hemorheological parameters as the whole blood viscosity (WBV) (high, middle, and low shear rate), PV, HCT, ESR and Fi.The male Tibet mini-pigs had significantly lower WBV (150, 30, 5, and 1 s(-1)) and Fi than the female mini-pigs (P0.05, 0.01, 0.05, 0.01, and 0.01, respectively). The WBV of male Beagle dogs (150 and 1 s(-1)) was significantly lower that in than female dogs (P0.05). The WBV of male human subjects (1 s(-1)) and HCT were significantly higher, but ESR significantly lower than those in female human subjects P0.05, 0.01 and 0.01, respectively). WBV (1 s(-1)), PV, and ESR in Beagle dogs were significantly lower, but HCT and Fi significantly higher than those in Tibet mini-pig and human subjects (P0.05, 0.01, 0.05, and 0.01, respectively). All the hemorheological parameters were similar between Tibet mini-pigs and human (P0.05).The hemorheological parameters of Tibet mini-pigs are closer to those of human than those of Beagle dogs.

To evaluate the effect of human hair keratin (HHK) in peripheral nerve repair and explore the mechanism of sciatic nerve regeneration.Rat models of sciatic nerve damage was established by creating a 10-mm gap in the sciatic nerve, which was bridged with a HHK implant. Histological examinations of the nerve tissues were performed at different time points after the surgery.During the period from 2 days to 2 weeks following HHK implantation, Schwann cells were found to undergo dedifferentiation and proliferate along the HHK implant. Three weeks after HHK implantation, numerous macrophages and megakaryocytes occurred around the HHK, and a large quantity of regenerated Schwann cells aligned in orderly fashion was seen between the fine filaments of partially degraded HHK, where axons and capillaries were also observed. Six weeks later, massive nerve fibers and capillaries developed around the HHK, and at 9 weeks, the HHK implant was substantially degraded and numerous regenerated nerve fibers occurred characterized by obvious epineurium and perineurium. Till 12 weeks after HHK implantation, HHK was almost completely degraded and replaced by the newly regenerated nerve fibers that had grown across the nerve defect.HHK is an ideal material for nerve injury repair. Apocytosis plays a key role in the differentiation process of highly differentiated Schwann cells into immature Schwann cells following nerve injury. As a protective mechanism, the axons undergo enclosure and dissociation following injuries, and the intact axons give rise to growth cones that extend fibers of growing buds to competitively bind the one or more Schwann cells, but only one such but finally develops into a complete axon. The nerve fiber barrier membrane is derived from the capillary menchymal stem cells and the outmost vascular barrier membrane. The regeneration of the Schwann cells, axons and the nerve membrane is the result of self-organization through a well synchronized and coordinated mechanism.

To evaluate the feasibility of establishing transgenic mice by means of seminiferous tubule microinjection and electroporation (EP) in vivo.Specific pathogen-free (SPF) male Kunming mice divided into 4 groups were subjected to microinjection of two different transfection solutions labeled with enhance green fluorescent protein (EGFP) into the seminiferous tubule of the testis, and in one of the two groups receiving the identical transfection solutions, EP in vivo was performed. After two weeks, the male mice of each group were mated with SPF female Kunming mice with superovulation treatment, and PCR coupled with Southern blotting was performed for the offspring mice.The results of PCR suggested significant difference in the efficiency of exogenous gene integration between the 4 groups (P0.01), among which group A achieved the greatest efficiency (45%). Southern blotting did not identify significant difference between the 4 groups (P0.05), but still suggested the highest efficiency in group A (25%).Seminiferous tubule microinjection in conjunction with subsequent EP in vivo can remarkably enhance the integration efficiency of exogenous genes into the host genome, but this new method needs to be further tested for its potential utility in transgenic animal generation.

The integral mature peptide gene of human growth differentiation factor-5 (GDF-5) was cloned to provide the essential foundation for study on the biological characteristics of GDF-5 at gene and protein levels. Two primers were chemosynthesized according to the hGDF-5 sequence reported in Genbank. The hGDF-5 gene was gained by RT-PCR methods from the total RNA extracted from human fetus cartilage tissue, and was cloned into vector pMD18-T. The sequence of recombinant plasmid pMD18-T-hGDF-5 was analyzed by sequence analysis. DNA agarose gel electrophoresis showed that the product of RT-PCR was about 380bp, and double enzyme digestion of the recombinant plasmid corresponded with it. The result of sequence assay was in agreement with the reported hGDF-5 sequence in Genbank. Our results showed that the integral mature peptide gene of human GDF-5 was cloned successfully from human fetal cartilage tissue, and totally identified with the sequence of human GDF-5 in Genbank.