Primary oocytes with cellular senescence features are involved in ovarian aging in mice.

In mammalian females, quiescent primordial follicles serve as the ovarian reserve and sustain normal ovarian function and egg production via folliculogenesis. The loss of primordial follicles causes ovarian aging. Cellular senescence, characterized by cell cycle arrest and production of the senescence-associated secretory phenotype (SASP), is associated with tissue aging. In the present study, we report that some quiescent primary oocytes in primordial follicles become senescent in adult mouse ovaries. The senescent primary oocytes share senescence markers characterized in senescent somatic cells. The senescent primary oocytes were observed in young adult mouse ovaries, remained at approximately 15% of the total primary oocytes during ovarian aging from 6 to 12 months, and accumulated in aged ovaries. Administration of a senolytic drug ABT263 to 3-month-old mice reduced the percentage of senescent primary oocytes and the transcription of the SASP factors in the ovary, in addition, led to increased numbers of primordial and total follicles and a higher rate of oocyte maturation. Our study provides experimental evidence that primary oocytes, a germline cell type that is arrested in meiosis, become senescent in adult mouse ovaries and that senescent cell clearance reduced primordial follicle loss and mitigated ovarian aging phenotypes.

Primary oocytes with cellular senescence features are involved in ovarian aging in mice.

In mammalian females, quiescent primordial follicles serve as the ovarian reserve and sustain normal ovarian function and egg production via folliculogenesis. The loss of primordial follicles causes ovarian aging. Cellular senescence, characterized by cell cycle arrest and production of the senescence-associated secretory phenotype (SASP), is associated with tissue aging. In the present study, we report that some quiescent primary oocytes in primordial follicles become senescent in adult mouse ovaries. The senescent primary oocytes share senescence markers characterized in senescent somatic cells. The senescent primary oocytes were observed in young adult mouse ovaries, remained at approximately 15% of the total primary oocytes during ovarian aging from 6 months to 12 months, and accumulated in aged ovaries. Administration of a senolytic drug ABT263 to 3-month-old mice reduced the percentage of senescent primary oocytes and the transcription of the SASP cytokines in the ovary. In addition, led to increased numbers of primordial and total follicles and a higher rate of oocyte maturation and female fertility. Our study provides experimental evidence that primary oocytes, a germline cell type that is arrested in meiosis, become senescent in adult mouse ovaries and that senescent cell clearance reduced primordial follicle loss and mitigated ovarian aging phenotypes.

Association of X-linked TLR-7 gene polymorphism with the risk of knee osteoarthritis: a case-control study.

Knee osteoarthritis (OA) is the most prevalent type of OA, and Toll-like receptor 7 (TLR7) may lead to the pathogenesis of OA. Recently, X-linked TLR7 polymorphism has been confirmed to be associated with arthritis. However, there is a lack of studies on TLR7 gene polymorphism associated with knee OA susceptibility. The current study aimed to determine whether TLR7 gene polymorphism is associated with the risk of knee OA. Genotyping of two polymorphic sites (rs3853839 and rs179010) in the TLR7 gene was performed in 252 OA patients, and 265 healthy controls using the SNaPshot sequencing technique. Data were analyzed statistically by Chi-square tests and logistic regression. Rs3853839-C allele showed frequencies of 28% and 27% in the healthy control and female knee OA groups, respectively. The differences were not statistically significant (P > 0.05). The rs3853839-CG genotype frequency was significantly lower in the female knee OA group as compared to the healthy control group (OR 0.60; 95%CI 0.36-0.99; P = 0.044). In the male hemizygote population, the rs3853839-CC showed significantly lower frequencies in the male knee OA group as compared to the healthy control group (OR 0.35; 95%CI 0.17-0.71; P = 0.0025). Regarding rs179010, there were no differences in the genotype distribution and allele frequencies between OA patients and healthy subjects under any models (P > 0.05). Stratified analysis showed that the frequency of the rs3853839-CG genotypes was lower in high Kellgren-Lawrence grades (KLG) (OR 0.48; 95%CI 0.21-1.08; P = 0.066), and significantly lower in OA patients with effusion synovitis (OR 0.38; 95%CI 0.17-0.88; P = 0.013). TLR7 rs3853839 polymorphism may play a role in the susceptibility of knee OA in the Chinese Han Population and may be associated with OA severity and the risk of effusion synovitis in Knee OA.

The Elusive Endometrial Epithelial Stem/Progenitor Cells.

The human endometrium undergoes approximately 450 cycles of proliferation, differentiation, shedding and regeneration over a woman's reproductive lifetime. The regenerative capacity of the endometrium is attributed to stem/progenitor cells residing in the basalis layer of the tissue. Mesenchymal stem cells have been extensively studied in the endometrium, whereas endometrial epithelial stem/progenitor cells have remained more elusive. This review details the discovery of human and mouse endometrial epithelial stem/progenitor cells. It highlights recent significant developments identifying putative markers of these epithelial stem/progenitor cells that reveal their in vivo identity, location in both human and mouse endometrium, raising common but also different viewpoints. The review also outlines the techniques used to identify epithelial stem/progenitor cells, specifically in vitro functional assays and in vivo lineage tracing. We will also discuss their known interactions and hierarchy and known roles in endometrial dynamics across the menstrual or estrous cycle including re-epithelialization at menses and regeneration of the tissue during the proliferative phase. We also detail their potential role in endometrial proliferative disorders such as endometriosis.

Applying Intravenous Immunoglobulin and Negative-Pressure Wound Therapy to Treat Refractory Pyoderma Gangrenosum: A Case Report.

Pyoderma gangrenosum (PG) is a rare chronic neutrophilic dermatosis that causes undermining ulcers. Unfortunately, standardization of PG treatment remains a challenge. In this article, we describe a case in which a 69-year-old man presented with a painful ulcer on the right lower leg. The diagnosis of PG was made after excluding other diseases. He had a history of PG on his left lower leg 2 years earlier and was cured by the treatment of systemic corticosteroids and cyclosporin A for 43 days. However, such a treatment was not effective this time. Hence, we applied intravenous immunoglobulin and negative-pressure wound therapy, and the patient was cured. Altogether, this case supports the use of intravenous immunoglobulin as an effective adjuvant for refractory PG, and indicates negative-pressure wound therapy as a treatment option to advance ulcer healing under adequate immunosuppression.

Bipotent stem cells support the cyclical regeneration of endometrial epithelium of the murine uterus.

The endometrial epithelium of the uterus regenerates periodically. The cellular source of newly regenerated endometrial epithelia during a mouse estrous cycle or a human menstrual cycle is presently unknown. Here, I have used single-cell lineage tracing in the whole mouse uterus to demonstrate that epithelial stem cells exist in the mouse uterus. These uterine epithelial stem cells provide a resident cellular supply that fuels endometrial epithelial regeneration. They are able to survive cyclical uterine tissue loss and persistently generate all endometrial epithelial lineages, including the functionally distinct luminal and glandular epithelia, to maintain uterine cycling. The uterine epithelial stem cell population also supports the regeneration of uterine endometrial epithelium post parturition. The 5-ethynyl-2'-deoxyuridine pulse-chase experiments further reveal that this stem cell population may reside in the intersection zone between luminal and glandular epithelial compartments. This tissue distribution allows these bipotent uterine epithelial stem cells to bidirectionally differentiate to maintain homeostasis and regeneration of mouse endometrial epithelium under physiological conditions. Thus, uterine function over the reproductive lifespan of a mouse relies on stem cell-maintained rhythmic endometrial regeneration.

Lignans-rich extract from Herpetospermum caudigerum alleviate physical fatigue in mice.

OBJECTIVE: To ascertain anti-fatigue constituents and mechanisms of Herpetospermum caudigerum. METHODS: The 80% ethanol extracts of Herpetospermum caudigerum were partitioned with chloroform, ethyl acetate and n-butanol, respectively. Male Kunming mice were divided into 13 groups with 16 mice in each group: a control group fed with water, 9 groups treated with 3 fractions of Herpetospermum caudigerum (chloroform fraction, ethyl acetate fraction and n-butanol fraction) at dose of 80, 160 and 320 mg/kg for the low-dose group, medium-dose group and high-dose group, 3 herpetrione (HPE) treated groups fed with HPE at dose of 15, 30, and 60 mg/kg for the low-dose group, medium-dose group and high-dose group. All animals were treated once per day for 30 days. Anti-fatigue activity was assessed through the forced swimming test and serum biochemical parameters including blood lactic acid (BLA), blood urea nitrogen (BUN), malondialdehyde (MDA), hepatic glycogen (HG), lactic dehydrogenase (LDH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) determined following the recommended procedures provided by the commercial kits. RESULTS: Compared with the control group, the lignans extract (ethyl acetate fraction) of Herpetospermum caudigerum and HPE could signifificantly prolonged the exhaustive swimming time (P<0.05 or P<0.01), and also increased the HG levels (P<0.05 or P<0.01) and the activities of antioxidant enzymes (SOD, GPx and LDH, P<0.05 or P<0.01); BLA and MDA levels were decreased considerably in lignans extract and HPE treated groups (P<0.05 or P<0.01). HPE also could significantly decrease the BUN contents compared with the control group (P<0.05). The chloroform and n-butanol fraction showed no effect on swimming time and biochemical parameters. CONCLUSIONS: The lignans extract had antifatigue activities and HPE may be partly responsible for the anti-fatigue effects of Herpetospermum caudigerum. The possible mechanisms of anti-fatigue activity were related to the decrease of BUN and BLA, the increase of the HG storage and protecting corpuscular membrane by preventing lipid oxidation via modifying several enzyme activities.

Transplantation of alginate-encapsulated seminiferous tubules and interstitial tissue into adult rats: Leydig stem cell differentiation in vivo?

In vivo and in vitro studies were conducted to determine whether testosterone-producing Leydig cells are able to develop from cells associated with rat seminiferous tubules, interstitium, or both. Adult rat seminiferous tubules and interstitium were isolated, encapsulated separately in alginate, and implanted subcutaneously into castrated rats. With implanted tubules, serum testosterone increased through two months. Tubules removed from the implanted rats and incubated with LH produced testosterone, and cells on the tubule surfaces expressed steroidogenic enzymes. With implanted interstitial tissue, serum levels of testosterone remained undetectable. However, co-culture of interstitium plus tubules in vitro resulted in the formation of Leydig cells by both compartments. These results indicate that seminiferous tubules contain both cellular and paracrine factors necessary for the differentiation of Leydig cells, and that the interstitial compartment contains precursor cells capable of forming testosterone-producing Leydig cells but requires stimulation by paracrine factors from the seminiferous tubules to do so.

Knockout of the transcription factor Nrf2: Effects on testosterone production by aging mouse Leydig cells.

Aging in rodents and men is associated with reduced serum levels of testosterone and Leydig cell testosterone productions. To further investigate the mechanism by which Leydig cell testosterone production declines, the effect of knocking out Nrf2, a master regulator of phase 2 antioxidant genes, was examined. In wild-type mice, testosterone production and serum testosterone levels remained unchanged through middle age (8 months), but then were reduced significantly by old age (21-24 months). In contrast, serum testosterone levels and Leydig cell testosterone production were reduced significantly in the Nrf2-/- mice as early as middle age, and were reduced further in the aged mice. Reduced steroidogenesis in the knockout mice was associated with reduced antioxidant capacity, and increased expression of protein nitrotyrosine residues, a marker of ROS. These results support the hypothesis that, over time, increases in oxidative stress contribute to or cause the reduced testosterone production that characterizes Leydig cell aging.

Gas1 is a receptor for sonic hedgehog to repel enteric axons.

The myenteric plexus of the enteric nervous system controls the movement of smooth muscles in the gastrointestinal system. They extend their axons between two peripheral smooth muscle layers to form a tubular meshwork arborizing the gut wall. How a tubular axonal meshwork becomes established without invading centrally toward the gut epithelium has not been addressed. We provide evidence here that sonic hedgehog (Shh) secreted from the gut epithelium prevents central projections of enteric axons, thereby forcing their peripheral tubular distribution. Exclusion of enteric central projections by Shh requires its binding partner growth arrest specific gene 1 (Gas1) and its signaling component smoothened (Smo) in enteric neurons. Using enteric neurons differentiated from neurospheres in vitro, we show that enteric axon growth is not inhibited by Shh. Rather, when Shh is presented as a point source, enteric axons turn away from it in a Gas1-dependent manner. Of the Gαi proteins that can couple with Smo, G protein α Z (Gnaz) is found in enteric axons. Knockdown and dominant negative inhibition of Gnaz dampen the axon-repulsive response to Shh, and Gnaz mutant intestines contain centrally projected enteric axons. Together, our data uncover a previously unsuspected mechanism underlying development of centrifugal tubular organization and identify a previously unidentified effector of Shh in axon guidance.

Comparison of anti-bacterial activity of three types of di-O-caffeoylquinic acids in Lonicera japonica flowers based on microcalorimetry.

The anti-bacterial activities of three types of di-O-caffeoylquinic acids (diCQAs) in Lonicera japonica flowers, a traditional Chinese medicine (TCM), on Bacillus shigae growth were investigated and compared by microcalorimetry. The three types of diCQAs were 3, 4-di-O-caffeoylquinic acid (3, 4-diCQA), 3, 5-di-O-caffeoylquinic acid (3, 5-diCQA), and 4, 5-di-O-caffeoylquinic acid (4, 5-diCQA). Some qualitative and quantitative information of the effects of the three diCQAs on metabolic power-time curves, growth rate constant k, maximum heat-output power Pm, and the generation time tG, total heat output Qt, and growth inhibitory ratio I of B. shigae were calculated. In accordance with a thermo-kinetic model, the corresponding quantitative relationships of k, Pm, Qt, I and c were established. Also, the half-inhibitory concentrations of the drugs (IC50) were obtained by quantitative analysis. Based on the quantity-activity relationships and the IC50 values, the sequence of inhibitory activity was 3, 5-diCQA > 4, 5-diCQA > 3, 4-diCQA. The results illustrate the possibility that the caffeoyl ester group at C-5 is the principal group that has a higher affinity for the bacterial cell, and that the intramolecular distance of the two caffeoyl ester groups also has an important influence on the anti-bacterial activities of the diCQAs.

[Preparation of baicalin nanocrystal pellets and preliminary study on its pharmacokinetics].

OBJECTIVE: To prepare baicalin nanocrystal (BC-NC) and evaluate its pharmacokinetics in rats. METHOD: Baicalin nanosuspensions (BC-NS) were prepared by the high pressure homogenization technology combined with ultrasonic, and then BC-NS were solidificated into BC-NC pellets by removing the water through fluid-bed drying. Its morphology, mean diameter and Zeta-potential were determined. An HPLC method was employed to determine the concentration of baicalin in plasma, and the bioavailability of the nanocrystal was compared with the reference group by oral administration in Wistar rats. RESULT: The nanocrystals observed by scanning electron microscopy were irregular granulated, and the mean particle sizes of BC-NC were (248 +/- 6) nm. Its polydispersity index (PI) and zeta-potential were (0.181 +/- 0.065), (-32.3 +/- 1.8) mV, respectively. The pharmacokinetic parameters showed that the C(max) was (16.54 +/- 1.73) mg x L(-1) and the AUC(0-24 h) was (206.96 +/- 21.23) mg x L(-1) x h, which were significantly enhanced compared with the baicalin bulk and baicalin physical mixture (BC-PM) formulation, respectively (P < 0.01). CONCLUSION: Baicalin nanocrystal can significantly improve the bioavailability of baicalin.

Enhanced intestinal absorption activity and hepatoprotective effect of herpetrione via preparation of nanosuspensions using pH-dependent dissolving-precipitating/homogenization process.

OBJECTIVES: The main purpose of this study was to enhance the intestinal absorption activity and hepatoprotective effect of herpetrione by drug nanosuspensions. METHODS: Herpetrione nanosuspensions (HNS) were prepared using pH-dependent dissolving-precipitating/homogenization process and then systematically characterized. The intestinal absorption activity of HNS were studied using the recirculating perfusion technique in comparison with herpetrione coarse suspensions (HCS) and pure herpetrione using the recirculating perfusion technique. The protective effect of HNS against acute liver injury induced by carbon tetrachloride (CCl4 ) in mice was also investigated and compared with that of HCS. KEY FINDINGS: The mean particle size of HNS was 269 ± 7 nm with a polydispersity index of 0.187 ± 0.021. The result of X-ray powder diffraction indicated that herpetrione was in amorphous state in both coarse powder and nanosuspensions. The intestinal absorption activity of HNS were superior to the HCS and pure herpetrione. As evidenced by the lowering of serum aminotransferase levels and the improvement of the degree of liver lesion, pretreatment with HNS markedly enhanced the hepatoprotective effect of herpetrione against acute liver injury induced by CCl4 in mice. CONCLUSION: HNS prepared using pH-dependent dissolving-precipitating/homogenization technique are able to significantly enhance the intestinal absorption activity and the hepatoprotective effect of herpetrione due to the particle size reduction.

Schisandra lignans-loaded enteric nanoparticles: preparation, characterization, and in vitro-in vivo evaluation.

Schisandrae lignans (SL) have been well proven to possess hepatoprotective effect against the hepatic dysfunction induced by various chemical hepatotoxins. Deoxyschisandrin (DA) and schisantherin A (SA) are both considered as the major active components in SL. The objective of the study was to prepare and evaluate Schisandra lignans (composed of DA and SA)-loaded enteric nanoparticles produced by a novel toxic solvent-free modified spontaneous emulsification solvent diffusion (SESD) method. An organic Schisandra lignans/Eudragit(®) S100 solution was injected into an aqueous poloxamer 188 solution under a agitation. The nanoparticles were characterized with respect to particle size distribution, morphology, encapsulation efficiency (EE) and physical stability of the drug, wettability, in vitro release and in vivo bioavailability. Nanoparticles with a smooth surface and dense structure were obtained with high EE (EE(DA) >90%; EE(SA) >85%). The drug was in a noncrystalline state in the matrix and physically stable for 120 days at room temperature. In vitro drug release study, the drug dissolution rate from the nanoparticles was significantly enhanced compared to the physical mixture and to the pure drug; the release profile of the nanoparticles was stable after 120 days. The appropriate size of nanoparticles (~93 nm), the solubilization of the surfactant, the noncrystalline state of the drug in the matrix and the fast dissolution rate contributed to a significantly enhanced oral bioavailability from the nanoparticles when compared to pure drug suspension.

Gastrointestinal defects of the Gas1 mutant involve dysregulated Hedgehog and Ret signaling.

The gastrointestinal (GI) tract defines the digestive system and is composed of the stomach, intestine and colon. Among the major cell types lining radially along the GI tract are the epithelium, mucosa, smooth muscles and enteric neurons. The Hedgehog (Hh) pathway has been implicated in directing various aspects of the developing GI tract, notably the mucosa and smooth muscle growth, and enteric neuron patterning, while the Ret signaling pathway is selectively required for enteric neuron migration, proliferation, and differentiation. The growth arrest specific gene 1 (Gas1) encodes a GPI-anchored membrane protein known to bind to Sonic Hh (Shh), Indian Hh (Ihh), and Ret. However, its role in the GI tract has not been examined. Here we show that the Gas1 mutant GI tract, compared to the control, is shorter, has thinner smooth muscles, and contains more enteric progenitors that are abnormally distributed. These phenotypes are similar to those of the Shh mutant, supporting that Gas1 mediates most of the Shh activity in the GI tract. Because Gas1 has been shown to inhibit Ret signaling elicited by Glial cell line-derived neurotrophic factor (Gdnf), we explored whether Gas1 mutant enteric neurons displayed any alteration of Ret signaling levels. Indeed, isolated mutant enteric progenitors not only showed increased levels of phospho-Ret and its downstream effectors, phospho-Akt and phospho-Erk, but also displayed altered responses to Gdnf and Shh. We therefore conclude that phenotypes observed in the Gas1 mutant are due to a combination of reduced Hh signaling and increased Ret signaling.

Development and in vivo/in vitro evaluation of novel herpetrione nanosuspension.

Herpetrione (HPE), is a new compound extracted from Herpetospermum caudigerum, which is proved to be a novel and potent antiviral agent. However, due to poor water solubility, oral bioavailability of the drug was relatively low. To improve the dissolution and absorption of the drug, formulation of HPE as nanosuspension has been performed in this study. HPE nanosuspension were produced by high pressure homogenization and transformed into dry powder by lyophilization. The nanosuspension was then investigated using photon correlation spectroscopy (PCS), zeta potential measurement, SEM and PXRD. To verify the theoretical hypothesis on the benefit of decreased particle size and increased surface area, in vitro dissolution characterization and in vivo pharmacokinetics were investigated. The inhibitory effect on HBsAg, HBeAg, and HBV-DNA of HPE nanosuspension in 2.2.15 cells was studied. Results showed that a narrow size distributed nanosuspension with a mean particle size of 286±1.3 nm, a polydispersity index of 0.18±0.06 and a zeta potential of -26.9±2.4 mV was obtained. The result of PXRD showed that HPE was amorphous state in both coarse powder and nanosuspension. In the in vitro dissolution test, HPE nanosuspension showed an increased dissolution velocity markedly. In the in vivo evaluation, compared to coarse HPE, nanosuspension exhibited significant increase in AUC(0-t), C(max) and decrease in T(max), MRT. The inhibitory effect of HBsAg, HBeAg, and HBV-DNA of 2.2.15 cells treated by HPE nanosuspension were stronger than those of the HPE. The in vitro activity experiments provided evidence for an enhanced efficacy of the HPE nanosuspension formulation compared to HPE coarse suspension. These results revealed that particle size reduction could enhance HPE dissolution rate and absorption in gastrointestinal tract, and nanosuspension might be a good choice for oral delivery of poor bioavailability drug like HPE.

Changes of pharmacokinetics of 6,7-dimethoxycoumarin in a rat model of alpha-naphthylisothiocyanate-induced experimental hepatic injury after Yinchenhao Decoction () treatment.

OBJECTIVE: To study the changes of pharmacokinetics of 6,7-dimethoxycoumarin in a rat model of alpha-naphthylisothiocyanate (ANIT)-induced experimental hepatic injury after oral administration of Yinchenhao Decoction (, YCHD) using an ultra pressure liquid chromatography (UPLC) method. METHODS: Rats were divided into a normal group and a model group, after modeled by 4% ANIT (75 mg/kg) for 48 h, they were orally administrated with YCHD extract at the dose of 0.324 g/kg, and then blood was collected from their orbital sinus after different intervals. Changes in liver function were monitored by the levels of liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST)] and bilirubins [total bilirubin (TBIL), direct bilirubin (DBIL)], the concentration of 6,7-dimethoxycoumarin in plasma were measured by UPLC, and the pharmaceutical parameters were calculated with DAS2.1.1 software. RESULTS: The concentration-time curve of both normal and modeled rats after oral administration of YCHD was obtained. Their time to maximum plasma concentration (t(max)) were both 0.25 h, the maximum concentration (C(max)) were 4.533 µg/mL and 6.885 µg/mL, and their area under concentration-time curve (AUC)(0→24h) were 16.272 and 32.981, respectively. There was a 51.88% and 100.46% increase in C(max) and AUC(0-t) (P<0.05), but there showed a 45.52% and 92.93% reduction in clearance of drug and volum of distribution (P<0.05), respectively. CONCLUSIONS: Hepatic injury could significantly influence the pharmacokinetics of 6,7-dimethoxycoumarin after oral administration of YCHD, the absorption and distribution process was accelerated in liver injured rats, but the metabolism and elimination process was slowed. And this may lead to a significant accumulation of 6,7-dimethoxycoumarin in the body.

Identification, proliferation, and differentiation of adult Leydig stem cells.

Leydig cells, the testosterone-producing cells of the adult testis, rarely turn over. However, their elimination with ethane dimethanesulfonate (EDS) is followed by the appearance of new, fully functional adult Leydig cells. The cells that give rise to the new Leydig cells have not been well characterized, and little is known about the mechanism by which they are regulated. We isolated cells expressing platelet-derived growth factor receptor-α, but not 3ß-hydroxysteroid dehydrogenase (3ß-HSD(neg)) from the testes of EDS-treated adult rats. Depending on conditions, these cells proliferated indefinitely or differentiated and produced testosterone. To localize these cells and to determine the effect of the testicular environment on their function, the seminiferous tubules and testicular interstitium were physically separated and cultured. During the first 72 h in culture, 3ß-HSD(neg) cells on the tubule surfaces underwent divisions. Some of these cells later expressed 3ß-HSD and produced testosterone. Removal of the newly formed 3ß-HSD(pos) cells from the tubule surfaces with EDS, followed by further culture of the stripped tubules, resulted in the reappearance of testosterone-producing cells. These results, taken together, suggest that the precursors for newly formed Leydig cells are stem cells, with many if not all situated on the surfaces of the seminiferous tubules. Although normally quiescent, the stem cells are capable of self-renewal and differentiation. The development of the tubule culture system should provide a valuable in vitro approach to assess the role(s) of niche components on the function of adult Leydig stem cells despite their residing in a complex mammalian tissue.

Improvement of oral bioavailability of glycyrrhizin by sodium deoxycholate/phospholipid-mixed nanomicelles.

Glycyrrhizin (GL), extracted from the Glycyrrhiza glabra L., is active triterpenoid saponin components. However, due to its impermeability across the gastrointestinal mucosa, oral bioavailability of the drug was relatively low. To improve its oral bioavailability, formulation of GL as sodium deoxycholate/phospholipid-mixed nanomicelles (SDC/PL-MMs) has been performed in this study. GL-SDC/PL-MMs were produced by a film dispersion method and then investigated using photon correlation spectroscopy (PCS), zeta potential measurement, as well as its physical stability after storage for 10, 20, 30, 60, 90 and 120 days. To verify the theoretical hypothesis, pharmacokinetics and pharmacodynamic studies based on carbon tetrachloride (CCl(4))-induced acute liver injury was investigated. Results showed that a narrow size distributed nanomicelles with a mean particle size of 82.99 ± 7.5 nm and a zeta potential of -32.23 ± 1.05 mV was obtained. In the pharmacokinetics, GL-SDC/PL-MMs show a significant superiority in AUC(0-t), C(max) and other pharmacokinetic parameters compared with the control group. In the pharmacodynamic studies, compared with the bifendate control group, GL-SDC/PL-MMs showed an equivalent effect in reducing alanine aminotransferase (ALT), aspartate aminotransferase (AST) and improving the pathological changes of liver tissue. These results revealed that SDC/PL-MMs could enhance GL absorption in gastrointestinal tract and pharmacodynamic effect in the treatment of acute liver injury caused by CCl(4), and SDC/PL-MMs might be a good choice for oral delivery of poor bioavailability drug like GL.