ObjectiveTo investigate the mechanism of Buzhong Yiqitang in attenuating cisplatin resistance in non-small cell lung cancer by observing the effects of Buzhong Yiqitang on endoplasmic reticulum stress-related molecules in human lung adenocarcinoma cells （A549） and cisplatin-resistant cells in human lung adenocarcinoma cells （A549/DDP） via the nuclear factor E₂-related factor 2（Nrf2）/reactive oxygen species（ROS） pathway. MethodsThe serum containing Buzhong Yiqitang was prepared and A549 cells and A549/DDP cells were cultured. The cells were randomized into groups A （A549 cells+blank serum）， B （A549 cells+20 mg·L^-1 cisplatin+blank serum）， C （A549 cells+20 mg·L^-1 cisplatin+10% Buzhong Yiqitang-containing serum）， D （A549/DDP cells+blank serum）， E （A549/DDP cells+20 mg·L^-1 cisplatin+blank serum）， and F （A549/DDP cells+20 mg·L^-1 cisplatin+10% Buzhong Yiqitang-containing serum）. The cell counting kit-8 （CCK-8） method was used to detect the half maximal inhibitory concentration （IC₅₀） of cisplatin. The protein levels of Nrf2 and p-Nrf2 were determined by Western blotting. The DCFH-DA fluorescent probe was used to measure the content of reactive oxygen species （ROS） in each group. The protein levels of glucose-regulated protein 78 （GRP78）， activated transcription factor 6 （ATF6）， and C/EBP-homologous protein （CHOP） were determined by Western blot. ResultsCompared with group B， group C showed a reduction in IC₅₀ of cisplatin （P<0.05）， which held true in group E compared with group F （P<0.05）. Moreover， the IC₅₀ of cisplatin to A549/DDP cells was higher than that to A549 cells before and after Buzhong Yiqitang intervention （P<0.05）. Compared with group A， group B showed up-regulated protein levels of Nrf2 and p-Nrf2 （P<0.05）. Compared with group B， group C showed down-regulated protein levels of Nrf2 and p-Nrf2 （P<0.05）. Compared with group D， group E showed up-regulated protein levels of Nrf2 and p-Nrf2 （P<0.05）， which， however， were significantly down-regulated in group F （P<0.05）. The ROS content and the protein levels of GRP78， ATF6， and CHOP followed a descending trend of group C > group B > group A in A549 cells and group F > group E > group D in A549/DDP cells （P<0.05）. Moreover， the ROS content and the protein levels of GRP78， ATF6， and CHOP in A549 cells were higher than those in A549/DDP cells before and after Buzhong Yiqitang intervention （P<0.05）. ConclusionBuzhong Yiqitang may regulate endoplasmic reticulum stress via the Nrf2/ROS pathway to attenuate cisplatin resistance in non-small cell lung cancer.

ObjectiveTo explore the possible mechanisms of Shujin Jiannao Formula （舒筋健脑方） for cerebral palsy. MethodsThirty 7-day-old SD rats were randomly divided into normal group， model group， and Shujin Jiannao Formula group， with 10 rats in each group. The model group and Shujin Jiannao Formula group established a cerebral palsy model by the classic Rice-Vannucci method. After successful modeling， rats in Shujin Jiannao Formula group were given Shujin Jiannao Formula 16 g/（kg·d） by gavage， while the normal group and model group were given normal saline 10 ml/（kg·d） by gavage once a day. After one week of intervention， the rats' body weight was measured， and Zea-Longa scores， the righting reflex test， and the hindlimb suspension test were conducted for assessment； hematoxylin-eosin （HE） staining and Nissl staining were used to observe pathological changes in brain tissue， and the number of Nissl-positive neurons was counted； enzyme-linked immunosorbent assay （ELISA） was employed to measure levels of inflammatory cytokines in the brain tissue， specifically interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α）； immunofluorescence was used to detect the expression levels of neurofilament protein 200 （NF200） and myelin basic protein （MBP） in brain tissue； Western Blot analysis was conducted to determine the protein levels of phosphoinositide 3-kinase （PI3K）， protein kinase B （Akt/PKB/Rac）， and mammalian target of rapamycin （mTOR） in brain tissue. ResultsCompared with the normal group， rats in the model group showed significantly higher Zea-Longa scores and lower scores in the hindlimb suspension test （P＜0.01）； pathological findings revealed loose structure in the cerebral cortex， hippocampal atrophy， and neuronal damage in brain tissue. Levels of IL-1β and TNF-α elevated， and the number of Nissl-stained positive neurons in the cortex and hippocampal CA1 region reduced， and immunofluorescence intensity of NF200 and MBP， as well as protein expression levels of PI3K and mTOR， significantly decreased （P＜0.05 or P＜0.01）. Compared with the model group， rats in Shujin Jiannao Formula group showed decreased Zea-Longa scores and increased hindlimb suspension test scores （P＜0.05）； pathological damage in brain tissue alleviated， levels of IL-1β and TNF-α reduced， the number of Nissl-stained positive neurons in the cortex and hippocampal CA1 region increased， and the immunofluorescence intensity of NF200 and MBP， as well as the protein levels of PI3K and mTOR， significantly elevated （P＜0.05 or P＜0.01）. There were no statistically significant differences among the groups in body weight， body-turning time， or AKT protein levels in brain tissue （P＞0.05）. ConclusionShujin Jiannao Formula can improve the neurological function of rats with cerebral palsy， exert neurorestorative effects， and its mechanism of action may be related to the reduction of inflammatory response in brain tissue and the activation of the PI3K/AKT/mTOR signaling pathway.

Tumors are the second leading cause of death worldwide. Exosomes are a type of extracellular vesicle secreted from multivesicular bodies, with particle sizes ranging from 40 to 160 nm. They regulate the tumor microenvironment, proliferation, and progression by transporting proteins, nucleic acids, and other biomolecules. Compared with other drug delivery systems, exosomes derived from different cells possess unique cellular tropism, enabling them to selectively target specific tissues and organs. This homing ability allows them to cross biological barriers that are otherwise difficult for conventional drug delivery systems to penetrate. Due to their biocompatibility and unique biological properties, exosomes can serve as drug delivery systems capable of loading various anti-tumor drugs. They can traverse biological barriers, evade immune responses, and specifically target tumor tissues, making them ideal carriers for anti-tumor therapeutics. This article systematically summarizes the methods for exosome isolation, including ultracentrifugation, ultrafiltration, size-exclusion chromatography (SEC), immunoaffinity capture, and microfluidics. However, these methods have certain limitations. A combination of multiple isolation techniques can improve isolation efficiency. For instance, combining ultrafiltration with SEC can achieve both high purity and high yield while reducing processing time. Exosome drug loading methods can be classified into post-loading and pre-loading approaches. Pre-loading is further categorized into active and passive loading. Active loading methods, including electroporation, sonication, extrusion, and freeze-thaw cycles, involve physical or chemical disruption of the exosome membrane to facilitate drug encapsulation. Passive loading relies on drug concentration gradients or hydrophobic interactions between drugs and exosomes for encapsulation. Pre-loading strategies also include genetic engineering and co-incubation methods. Additionally, we review approaches to enhance the targeting, retention, and permeability of exosomes. Genetic engineering and chemical modifications can improve their tumor-targeting capabilities. Magnetic fields can also be employed to promote the accumulation of exosomes at tumor sites. Retention time can be prolonged by inhibiting monocyte-mediated clearance or by combining exosomes with hydrogels. Engineered exosomes can also reshape the tumor microenvironment to enhance permeability. This review further discusses the current applications of exosomes in delivering various anti-tumor drugs. Specifically, exosomes can encapsulate chemotherapeutic agents such as paclitaxel to reduce side effects and increase drug concentration within tumor tissues. For instance, exosomes loaded with doxorubicin can mitigate cardiotoxicity and minimize adverse effects on healthy tissues. Furthermore, exosomes can encapsulate proteins to enhance protein stability and bioavailability or carry immunogenic cell death inducers for tumor vaccines. In addition to these applications, exosomes can deliver nucleic acids such as siRNA and miRNA to regulate gene expression, inhibit tumor proliferation, and suppress invasion. Beyond their therapeutic applications, exosomes also serve as tumor biomarkers for early cancer diagnosis. The detection of exosomal miRNA can improve the sensitivity and specificity of diagnosing prostate and pancreatic cancers. Despite their promising potential as drug delivery systems, challenges remain in the standardization and large-scale production of exosomes. This article explores the future development of engineered exosomes for targeted tumor therapy. Plant-derived exosomes hold potential due to their superior biocompatibility, lower toxicity, and abundant availability. Furthermore, the integration of exosomes with artificial intelligence may offer novel applications in diagnostics, therapeutics, and personalized medicine.

BACKGROUND:Repetitive trans-spinal magnetic stimulation(rTSMS)can inhibit inflammatory responses following spinal cord injury.rTSMS applies magnetic field stimulation to the spinal cord region to modulate neuronal excitability and synaptic transmission,thereby promoting plasticity and repair of the nervous system. OBJECTIVE:To observe the effects of rTSMS on the Toll-like receptor 4(TLR4)/nuclear factor(NF)-κB/NLRP3 signaling pathway after spinal cord injury and explore its mechanism in promoting motor function recovery. METHODS:Male C57BL/6J mice,SPF grade,were randomly divided into sham surgery group,spinal cord injury group,and rTSMS group.The latter two groups of mice were anesthetized and the T9 vertebral plate was removed using rongeur forceps to expose the spinal cord,and the spinal cord was clamped using a small aneurysm clip for 20 seconds to establish the spinal cord injury model.Mice in the rTSMS group underwent a 21-day rTSMS intervention starting on day 1 after spinal cord injury.The stimulation lasted 10 minutes per day,5 days per week with an interval of 2 days.Basso Mouse Scale scores were used to assess motor function recovery in mice after spinal cord injury at 1,3,7,14,and 21 days after spinal cord injury.Western blot was employed to detect the expression of AQP4,apoptotic factors Bax,Bcl-2,CL-Caspase-3,inflammatory factors tumor necrosis factor-α,interferon-γ,interleukin-6,interleukin-4,and the TLR4/NF-κB/NLRP3 signaling pathway related proteins in the injured spinal cord.Oxidative stress assay kit was used to measure the activity of superoxide dismutase,glutathione peroxidase,and malondialdehyde content at the site of spinal cord injury.Immunofluorescence staining was performed to detect the expression of neuronal nuclei(NeuN). RESULTS AND CONCLUSION:The Basso Mouse Scale score in the rTSMS group was significantly higher than that in the spinal cord injury group(P<0.05).Compared with the spinal cord injury group,the rTSMS group showed a reduction in spinal cord water content.The expression of AQP4 protein,malondialdehyde content,and expression of Bax,Bcl-2,CL-Caspase-3,tumor necrosis factor-α,interferon-γ,interleukin-6,and TLR4/NF-κB/NLRP3 signaling pathway related proteins were all decreased in the rTSMS group,while the activities of superoxide dismutase and glutathione peroxidase,as well as the expression of Bcl-2,interleukin-4,and NeuN,were all increased(P<0.05).These results suggest that rTSMS downregulates the expression of proteins related to the TLR4/NF-κB/NLRP3 signaling pathway,alleviating symptoms after spinal cord injury such as spinal cord edema,oxidative stress,apoptosis,and inflammation,exerting neuroprotective effects,and thereby promoting the recovery of hindlimb motor function after spinal cord injury.

Alzheimer’s disease (AD) is a prevalent neurodegenerative condition characterized by progressive cognitive decline and memory loss. As the incidence of AD continues to rise annually, researchers have shown keen interest in the active components found in natural plants and their neuroprotective effects against AD. Quercetin, a flavonol widely present in fruits and vegetables, has multiple biological effects including anticancer, anti-inflammatory, and antioxidant. Oxidative stress plays a central role in the pathogenesis of AD, and the antioxidant properties of quercetin are essential for its neuroprotective function. Quercetin can modulate multiple signaling pathways related to AD, such as Nrf2-ARE, JNK, p38 MAPK, PON2, PI3K/Akt, and PKC, all of which are closely related to oxidative stress. Furthermore, quercetin is capable of inhibiting the aggregation of β‑amyloid protein (Aβ) and the phosphorylation of tau protein, as well as the activity of β‑secretase 1 and acetylcholinesterase, thus slowing down the progression of the disease.The review also provides insights into the pharmacokinetic properties of quercetin, including its absorption, metabolism, and excretion, as well as its bioavailability challenges and clinical applications. To improve the bioavailability and enhance the targeting of quercetin, the potential of quercetin nanomedicine delivery systems in the treatment of AD is also discussed. In summary, the multifaceted mechanisms of quercetin against AD provide a new perspective for drug development. However, translating these findings into clinical practice requires overcoming current limitations and ongoing research. In this way, its therapeutic potential in the treatment of AD can be fully utilized.

AIM: To assess the stability of the tear film and the characteristics of corneal nerves in patients with Parkinson's disease(PD).METHODS: This cross-sectional observational study included 72 PD patients and 50 healthy controls. Disease severity was determined using the Hoehn-Yahr(H-Y)scale, dividing patients into mild and moderate PD groups. Dry eye symptoms were evaluated via the ocular surface disease index(OSDI)questionnaire, while tear secretion was quantified using the Schirmer I test. Ocular surface damage was assessed through staining scores, and comprehensive ocular examinations were performed utilizing the LipiView ocular surface interferometer and an ocular surface analyzer. Corneal nerve parameters were examined using corneal confocal microscopy in conjunction with automated analysis software ACCMetrics, with correlations drawn between these parameters, PD course, and severity.RESULTS: PD patients exhibited significantly elevated OSDI scores, indicative of more pronounced dry eye symptoms compared to the control group(F=70.290, P<0.01). Tear film stability was markedly compromised, with significantly shorter tear film breakup time and increased corneal fluorescein staining, both showing statistically significant differences relative to controls(all P<0.01). Tear secretion indices, including Schirmer I test results and tear meniscus height, were significantly reduced in PD patients(all P<0.01), whereas lipid secretion indices, such as lipid layer thickness and meibomian gland dropout score, did not show significant variation. Corneal nerve analysis revealed significant reductions in corneal nerve fiber density, nerve branch density, fiber length, and total branch density in PD patients compared to controls(all P<0.01). Furthermore, blink frequency was markedly prolonged(F=62.353, P<0.01). Correlation analysis demonstrated a significant relationship between alterations in tear film stability and both disease duration and H-Y scores.CONCLUSION: PD patients have obvious dry eye manifestations in the early stage of the disease, including the reduction of tear film stability and corneal nerve fiber density, and gradually aggravate with the progress of the disease. Neurodegenerative disease-related dry eye needs to be diagnosed early and actively treated.

Objective To clone and express the heat shock cognate protein 20 (SjHsc20) of Schistosoma japonicum, and to preliminarily investigate its biological characteristics. Methods The target fragment of the SjHsc20 gene was amplified using PCR assay and cloned into the pET-28a(+) expression plasmid to generate the recombinant expression vector pET-28a(+)-SjH-sc20, which was then transformed into Escherichia coli BL21 (DE3) competent cells. The recombinant SjHsc20 (rSjHsc20) protein was induced with isopropyl β-D-thiogalactopyranoside (IPTG) and purified, and the expression of the rSjHsc20 protein was checked with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The immunogenicity of the rSjHsc20 protein was detected using Western blotting, and the transcriptional levels of SjHsc20 were quantified in S. japonicum worms at different developmental stages and in male and female adult worms using real-time quantitative PCR (RT-qPCR) assay. Thirty female BALB/c mice at ages 6 to 8 weeks were divided into three groups, including the rSjHsc20 immunization group, the PBS control group, and the ISA 206 adjuvant group, of 10 mice in each group. Mice in the rSjHsc20 immunization group were subcutaneously immunized with 20 μg rSjHsc20 on days 1, 15 and 31, and animals in the PBS control group were subcutaneously injected with the same volume of PBS on days 1, 15 and 31, while mice in the ISA 206 adjuvant group were subcutaneously immunized with the same volume of ISA 206 adjuvant on days 1, 15 and 31, respectively. All mice in each group were infected with (40 ± 2) S. japonicum cercariae via the abdomen 14 day following the last immunization. Levels of serum specific IgG and its subtypes IgG1 and IgG2 antibodies against rSjHsc20, and the serum titers of anti-rSjHsc20 antibody were detected in mice using indirect enzyme-linked immunosorbent assay (ELISA). All mice were sacrifice 42 days post-infection, and S. japonicum worms were collected from the hepatic portal vein and counted. The eggs per gram (EPG), worm burden reductions and egg burden reductions were estimated to evaluate the protective efficacy of the rSjHsc20 protein. Results The SjHsc20 gene had an open reading frame (ORF) with 756 bp in length and encoded 252 amino acids, and the rSjHsc20 protein had a relative molecular mass of approximately 29 kDa. The rSjHsc20 protein was recognized by the serum of mice infected with S. japonicum and the serum of mice immunized with the rSjHsc20 protein, indicating that rSjHsc20 had a good immunogenicity. There was a significant difference in the transcriptional levels of the SjHsc20 gene among the 7-day (1.001 4 ± 0.065 7), 12-day (2.268 3 ± 0.129 2), 21-day (1.378 5 ± 0.160 4), 28-day (1.196 4 ± 0.244 0), 35-day (1.646 3 ± 0.226 1), 42-day worms of S. japonicum (1.758 0 ± 0.611 1) (F = 38.45, P < 0.000 1), and the transcriptional level of the SjHsc20 gene was higher in the 12-day worms than in worms at other developmental stages (all P values < 0.000 1). The serum levels of anti-rSjHsc20 IgG antibody were 0.106 6 ± 0.010 7, 0.108 3 ± 0.010 4, and 0.553 2 ± 0.069 1 in the PBS control group, ISA 206 adjuvant group, and rSjHsc20 immunization group following the last immunization, respectively, and the serum levels of IgG1 antibody were 0.137 3 ± 0.054 0, 0.181 1 ± 0.096 8, and 1.765 8 ± 0.221 1, while the levels of IgG2a antibody were 0.280 3 ± 0.197 6, 0.274 0 ± 0.146 3, and 1.560 4 ± 0.106 0, respectively. There were significant differences in the serum levels of anti-rSjHsc20 IgG (F = 397.70, P < 0.000 1), IgG1 (F = 401.00, P < 0.000 1) and IgG2a antibodies (F = 229.70, P < 0.000 1) among the three groups, and the serum levels of anti-rSjHsc20 IgG, IgG1 and IgG2a antibodies were higher in the rSjHsc20 immunization group than in the PBS control group and the ISA 206 adjuvant group (all P values < 0.000 1). There was a significant difference in the IgG1/IgG2a ratio among the rSjHsc20 immunization group (1.177 2 ± 0.143 6), the PBS control group (0.428 4 ± 0.199 8) and the ISA 206 adjuvant group (0.559 9 ± 0.181 1) (F = 43.97, P < 0.000 1), and the IgG1/IgG2a ratio was > 1 in the rSjHsc20 immunization group, which was higher than in the PBS control group and the ISA 206 adjuvant group (both P values < 0.000 1). The titers of serum anti-rSjHsc20 antibody were all above 1∶16 384 in the rSjHsc20 immunization group following immunizations on days 1, 15 and 31, indicating that the rSjHsc20 protein had a strong immunogenicity. The mean worm burdens were (16.60±5.75), (15.80±5.58) worms per mouse and (14.40±5.75) worms per mouse in the PBS control group, the ISA 206 adjuvant group and the rSjHsc20 immunization group 42 days post-infection with S. japonicum cercariae (F = 0.50, P > 0.05), and the EPG were 68 370 ± 22 690, 67 972 ± 19 502, and 41 075 ± 13 251 in the PBS control group, the ISA 206 adjuvant group and the rSjHsc20 immunization group (F = 4.55, P < 0.05), with lower EPG in the PBS control group and the ISA 206 adjuvant group than in the rSjHsc20 immunization group (both P values < 0.05). Immunization with the rSjHsc20 protein resulted in a worm burden reduction of 13.25% and an egg burden reduction of 39.92% relative to the PBS control group. Conclusions SjHsc20 is successfully cloned and expressed, and the rSjHsc20 protein induces partial immunoprotective effects in mice, which provides a basis for deciphering the biological functions of SjHsc20 and assessing the potential of SjH-sc20 as a vaccine candidate.

Background::Carotid intima-media thickness (IMT) and diameter, stiffness, and wave reflections, are independent and important clinical biomarkers and risk predictors for cardiovascular diseases. The purpose of the present study was to establish nationwide reference values of carotid properties for healthy Chinese adults and to explore potential clinical determinants.Methods::A total of 3053 healthy Han Chinese adults (1922 women) aged 18-79 years were enrolled at 28 collaborating tertiary centers throughout China between April 2021 and July 2022. The real-time tracking of common carotid artery walls was achieved by the radio frequency (RF) ultrasound system. The IMT, diameter, compliance coefficient, β stiffness, local pulse wave velocity (PWV), local systolic blood pressure, augmented pressure (AP), and augmentation index (AIx) were then automatically measured and reported. Data were stratified by age groups and sex. The relationships between age and carotid property parameters were analyzed by Jonckheere-Terpstra test and simple linear regressions. The major clinical determinants of carotid properties were identified by Pearson’s correlation, multiple linear regression, and analyses of covariance.Results::All the parameters of carotid properties demonstrated significantly age-related trajectories. Women showed thinner IMT, smaller carotid diameter, larger AP, and AIx than men. The β stiffness and PWV were significantly higher in men than women before forties, but the differences reversed after that. The increase rate of carotid IMT (5.5 &mu;m/year in women and 5.8 &mu;m/year in men) and diameter (0.03 mm/year in both men and women) were similar between men and women. For the stiffness and wave reflections, women showed significantly larger age-related variations than men as demonstrated by steeper regression slopes (all P for age by sex interaction <0.05). The blood pressures, body mass index (BMI), and triglyceride levels were identified as major clinical determinants of carotid properties with adjustment of age and sex. Conclusions::The age- and sex-specific reference values of carotid properties measured by RF ultrasound for healthy Chinese adults were established. The blood pressures, BMI, and triglyceride levels should be considered for clinical application of corresponding reference values.

Aim To investigate the mechanism of treatment of hepatolenticular degeneration with Garde-nia and Rhubarb decoction based on network pharma-cology and animal experiments.Methods The chemi-cal components and target sites of Gardenia and Rhu-barb decoction were retrieved using the Traditional Chi-nese Medicine System Pharmacology Analysis Platform(TCMSP).The disease targets were obtained by searching the databases of DisGeNET,GeneCards.The PPI network of active compound target sites was constructed using the STRING database.GO function and KEGG pathway enrichment analysis were per-formed using the DAVID database to predict the action pathway.A copper-loaded WD rat model was estab-lished by intragastric administration of copper sulfate pentahydrate.A total of 36 rats were randomly divided into the normal group,model group,penicillamine group and the low,medium and high dose groups of gardenia rhubarb.The relevant indicators and patho-logical changes of liver tissue were detected in WD rats.Results Network pharmacology screening identi-fied 68 potential active components of Gardenia and Rhubarb Decoction,30 intersection targets of diseases and drugs,involving key targets such as TNF,IL10,IGF1,IL1B,TP53,CASP3,PPARG,IL6,CXCL8,IL1A,TGFB1,mainly related to signal pathways such as MAPK,AGE-RAGE signaling pathway in diabetic complications.In the animal experiments,compared with the normal group,the urine copper,liver copper,blood copper,liver coefficient,serum and liver ALT,AST,TNF-α,CASP3,P53 levels in the model group rats significantly increased(P＜0.05);hepatocyte swelling,cytoplasm loose reticular appearance,feath-er-like degeneration and reticular necrosis were ob-served in liver tissue pathology;compared with the model group,the urine copper,liver copper,blood copper,liver coefficient,serum and liver ALT,AST,TNF-α,CASP3,P53 levels in the penicillamine group and Gardenia and Rhubarb decoction groups were sig-nificantly reduced(P＜0.05),and the degree of re-ticular necrosis in the rat liver cells in the penicilla-mine group and the Gardenia and Rhubarb decoction group was significantly reduced.Conclusions Garde-nia and Rhubarb decoction has the effect of regulating copper metabolism and reducing liver injury.The mechanism of action may be related to reversing apop-tosis and downregulating protein expression of TNF-α,CASP3,P53 in MAPK signaling pathway.

Perihilar cholangiocarcinoma(PHC)is a common malignancy of biliary tract,for which surgery is the most effective treatment.However,its prognosis is not satisfactory even after surgical resection.In recent years,there have been some new advances in the surgical treatment of PHC.In this paper,we reviewed the existing literatures,demonstrated the current situation of preoperative biliary drainage,liver hyperplasia,hepatic resection,liver transplantation and minimally invasive surgery in the treatment of PHC,and prospected the future research direction.