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Purpose The objective of this study was to compare the in vitro Fick’s first law, in vitro lipolysis, and in vivo rat assays for oral absorption of Biopharmaceutical Classification Systems Class II (BCS II) drugs in self-nanoemulsifying drug delivery system (SNEDDS), and studied drugs and oils properties effects on the absorption. Methods The transport abilities of griseofulvin (GRI), phenytoin (PHE), indomethacin (IND), and ketoprofen (KET) in saturated water solutions and SNEDDS were investigated using the in vitro Madin-Darby canine kidney cell model. GRI and cinnarizine (CIN) in medium-chain triglycerides (MCT)-SNEDDS and long-chain triglycerides (LCT)-SNEDDS were administered in the in vivo SD rat and in vitro lipolysis models to compare the oral absorption and the distribution behaviors in GIT and build an in vitro-in vivo correlation (IVIVC). Results In the cell model, the solubility of GRI, PHE, IND, and KET increased 6–8 fold by SNEDDS, but their permeability were only 18%, 4%, 8%, and 33% of those of their saturated water solutions, respectively. However, in vivo absorption of GRI-SNEDDS was twice that of the GRI suspension and those of CIN-SNEDDS were 15–21 fold those of the CIN suspension. In the lipolysis model, the GRI% in aqueous and pellet phases of MCT were similar to that in LCT. In contrast, the CIN% in the aqueous and pellet phases were decreased but that of the lipid phase increased. In addition, an IVIVC was found between the CIN% in the lipid phase and in vivo relative oral bioavailability ( F r ). Conclusion The in vitro cell model was still a suitable tool to study drug properties effects on biofilm transport and SNEDDS absorption mechanisms. The in vitro lipolysis model provided superior oral absorption simulation of SNEDDS and helped to build correlation with in vivo rats. The oral drug absorption was affected by drug and oil properties in SNEDDS.

The CREPT (cell cycle-related and expression elevated protein in tumor, also known as RPRD1B) and p15RS (p15 -related sequence, also known as RPRD1A) have been shown to regulate cell proliferation and alter the cell cycle through Wnt/β-catenin pathway downstream genes in human. Although several studies have revealed the mechanism by which CREPT and p15RS regulate cell proliferation in human and mammals, it is still unclear how these genes function in poultry. In order to determine the function of CREPT and p15RS in chicken, we examined the expression of CREPT and p15RS in a variety of chicken tissues and DF-1 cells. Then, we determined the effect of overexpression or depletion of CREPT or p15RS, by transiently transfecting chicken DF-1 cells with overexpression and short hairpin RNA (shRNA) vectors respectively, on the regulation of cell proliferation. The results showed that CREPT and p15RS had different expression patterns and opposite effects on the cell cycling and proliferation. Knockdown of p15RS expression or overexpression of CREPT facilitated cell proliferation by promoting the cell-cycle transition from G0/G1 to S-phase and G2/M, whereas knockdown of CREPT or overexpression of p15RS inhibited cell proliferation. Mechanistically, CREPT and p15RS control DF-1 cell proliferation by regulating the expression of Wnt/β-catenin pathway downstream regulatory genes, including β-catenin, TCF4, and Cyclin D1. In conclusion, CREPT and p15RS regulate cell proliferation and the cell-cycle transition in chicken DF-1 cells by regulating the transcription of Wnt/β-catenin pathway downstream regulatory genes.

A non-lipolysis nanoemulsion (NNE) was designed to reduce the first-pass metabolism of raloxifene (RAL) by intestinal UDP-glucuronosyltransferases (UGTs) for increasing the oral absorption of RAL, coupled with in vitro and in vivo studies. Methods: In vitro stability of NNE was evaluated by lipolysis and the UGT metabolism system. The oral bioavailability of NNE was studied in rats and pigs. Finally, the absorption mechanisms of NNE were investigated by in situ single-pass intestinal perfusion (SPIP) in rats, Madin-Darby canine kidney (MDCK) cells model, and lymphatic blocking model. Results: The pre-NNE consisted of isopropyl palmitate, linoleic acid, Cremophor RH40, and ethanol in a weight ratio of 3.33:1.67:3:2. Compared to lipolysis nanoemulsion of RAL (RAL-LNE), the RAL-NNE was more stable in in vitro gastrointestinal buffers, lipolysis, and UGT metabolism system (p < 0.05). The oral bioavailability was significantly improved by the NNE (203.30%) and the LNE (205.89%) relative to the suspension group in rats. However, 541.28% relative bioavailability was achieved in pigs after oral NNE intake compared to the suspension and had twofold greater bioavailability than the LNE (p < 0.05). The RAL-NNE was mainly absorbed in the jejunum and had high permeability at the intestine of rats. The results of both SPIP and MDCK cell models demonstrated that the RAL-NNE was absorbed via endocytosis mediated by caveolin and clathrin. The other absorption route, the lymphatic transport (cycloheximide as blocking agent), was significantly improved by the NNE compared with the LNE (p < 0.05). Conclusion: A NNE was successfully developed to reduce the first-pass metabolism of RAL in the intestine and enhance its lymphatic transport, thereby improving the oral bioavailability. Altogether, NNE is a promising carrier for the oral delivery of drugs with significant first-pass metabolism.

Fibroblast growth factors (FGFs) are essential in regulating the formation of spermatogonial stem cells (SSCs). Here, we explored the effect of FGF8 on chicken SSCs formation by knockdown or overexpression of FGF8 in chicken embryonic stem cells (ESCs) both in vitro and in vivo. Our results showed that knockdown of FGF8 could facilitate the differentiation of ESCs into SSCs, overexpression of FGF8 could promote PGCs self-renewal, inhibit SSCs formation. This study further revealed the positive correlation between the expression level of FGF8 and MAPK/ERK signal. In the absence of FGF8, the expression of downstream genes such as FGFR2, GRB2, RAS, BRAF, RAF1, and MEK2 was not maintained, while overexpressing FGF8 enhances them. Thus, our study demonstrated that FGF8 can regulate germ cell fate by modulating the dynamic equilibrium between differentiation and self-renewal, which provides a new idea for the study of germ cell regulatory network.