ObjectiveTo investigate the mechanisms by which Liuwei Buqi prescription （LWBQ） regulates alveolar macrophage efferocytosis and improves inflammatory responses in rats with chronic obstructive pulmonary disease （COPD） characterized by lung-kidney Qi deficiency based on the nuclear factor erythroid 2-related factor 2 （Nrf2）/macrophage receptor with collagenous structure （MARCO） pathway. MethodsSuccessfully modeled rats were randomly divided into a model group， low-dose LWBQ group （LWBQ-L， 2.25 g·kg^-1·d^-1）， medium-dose LWBQ group （LWBQ-M， 4.5 g·kg^-1·d^-1）， high-dose LWBQ group （LWBQ-H， 9 g·kg^-1·d^-1）， and aminophylline group （AMIN， 50 mg·kg^-1·d^-1）， with 8 rats in each group. Another 8 healthy rats were included as the blank group. Except for the blank group， rats in the remaining groups were subjected to smoke exposure combined with forced swimming， intratracheal lipopolysaccharide （LPS） instillation， and subcutaneous hydrocortisone injection to establish a COPD model with lung-kidney Qi deficiency. After successful modeling， rats were administered different doses of LWBQ or AMIN by gavage. Body weight， fur condition， and oral secretions were observed. Pulmonary function was measured using an animal lung function analyzer. Enzyme-linked immunosorbent assay （ELISA） was used to detect the expression levels of interferon-γ （IFN-γ）， interleukin-6 （IL-6）， interleukin-1 （IL-1）， and tumor necrosis factor-α （TNF-α） in bronchoalveolar lavage fluid （BALF） and serum （SER）. Hematoxylin-eosin （HE） staining was used to examine pathological changes in lung tissue. Giemsa staining was performed to detect eosinophils， basophils， and neutrophils in BALF. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） was used to detect apoptosis in lung tissue. Western blot and real-time polymerase chain reaction （Real-time PCR） were employed to determine the protein and mRNA expression levels of efferocytosis-related proteins growth arrest-specific gene 6 （GAS6）， milk fat globule-epidermal growth factor 8 （MFG-E8）， and pathway-related proteins Nrf2 and MARCO in lung tissue. ResultsCompared with the blank group， the model group showed reduced food intake， nasal and oral secretions with sputum， and decreased body weight （P<0.01）， decreased peak expiratory flow （PEF） （P<0.01）， increased forced vital capacity （FVC） （P<0.01）， and decreased forced expiratory volume in 0.3 s/forced vital capacity ［FEV0.3/FVC （%）］ （P<0.01）. The expression levels of IFN-γ， IL-6， IL-1， and TNF-α in BALF and SER were increased （P<0.01）. Lung tissue exhibited structural destruction， hyperplasia， inflammatory exudation， increased apoptotic cells， and increased mean optical density （P<0.01）. The protein and mRNA expression levels of GAS6， MFG-E8， and MARCO， as well as Nrf2 mRNA expression， were increased （P<0.01）. Compared with the model group， the LWBQ groups showed increased food intake， reduced nasal and oral secretions with sputum， and increased body weight （P<0.05， P<0.01）. PEF was increased （P<0.01）. FVC was increased in rats treated with low- and medium-dose LWBQ （P<0.01）， and FEV0.3/FVC （%） was increased in rats treated with medium- and high-dose LWBQ （P<0.05， P<0.01）. The expression levels of IFN-γ， IL-6， IL-1， and TNF-α in BALF and SER were decreased （P<0.01）. Lung tissue structure was relatively intact， with improvement in hyperplasia and inflammatory exudation. The number of apoptotic cells in lung tissue was reduced， and mean optical density was decreased （P<0.05， P<0.01）. The protein and mRNA expression levels of efferocytosis-related proteins GAS6 and MFG-E8 and pathway-related proteins Nrf2 and MARCO were increased （P<0.01）. ConclusionLWBQ can alleviate pulmonary and systemic inflammation， improve lung function， and reduce lung tissue damage in rats with COPD characterized by lung-kidney Qi deficiency. The mechanism may be related to enhancement of alveolar macrophage efferocytosis through regulation of the Nrf2/MARCO pathway.

ObjectiveTo investigate the effects and underlying mechanisms of Shenqi Wenfei prescription （SQWF） on chronic obstructive pulmonary disease （COPD）. MethodsA rat model of COPD with lung Qi deficiency was established using lipopolysaccharide （LPS） combined with cigarette smoke. Forty-eight SD rats were randomly divided into a blank group， a model group， low-， medium-， and high-dose SQWF groups （2.835， 5.67， 11.34 g·kg^-1）， and a Yupingfeng group （1.35 g·kg^-1）. Drug administration began on day 29 after modeling and continued for 2 weeks. The general condition of the rats was observed， and the lung function in each group was assessed. Hematoxylin-eosin （HE） staining was used to observe pathological changes in lung tissue. The proportion of inflammatory cells in bronchoalveolar lavage fluid （BALF） was measured. Apoptosis in lung tissue was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL） staining. The release level of lactate dehydrogenase （LDH） in BALF was detected by a microplate assay. Reactive oxygen species （ROS） levels in lung tissue were detected using fluorescent probes. The levels of malondialdehyde （MDA）， total superoxide dismutase （SOD）， and reduced glutathione （GSH） in BALF were measured by biochemical methods. Ultrastructural changes in lung cells were observed via transmission electron microscopy. Double immunofluorescence staining was performed to detect the expression of thioredoxin-interacting protein （TXNIP） and nucleotide-binding oligomerization domain-like receptor protein 3 （NLRP3） in lung tissue. Western blot analysis was used to detect the protein expression of TXNIP， NLRP3， apoptosis-associated speck-like protein containing a CARD （ASC）， cysteinyl aspartate-specific protease-1 （Caspase-1）， Caspase-1 p20， gasdermin D （GSDMD）， GSDMD N-terminal active fragment （GSDMD-N）， interleukin-1β （IL-1β）， and IL-18 in lung tissue. Serum IL-1β and IL-18 levels were measured by ELISA. ResultsCompared with the blank group， the model group showed lassitude， fatigue， tachypnea， and audible phlegm sounds， and lung function significantly declined （P0.01）. Pulmonary emphysema and inflammatory cell infiltration were obvious. The level of inflammatory cells in BALF increased significantly （P0.05）. The number of TUNEL-positive cells increased （P0.01）. Levels of LDH， ROS， and MDA in BALF increased significantly （P0.01）， while GSH and SOD activities decreased significantly （P0.01）. Lung tissue cells showed irregular morphology， swollen mitochondria， disrupted cell membranes， and abundant vesicles， i.e.， pyroptotic bodies. Protein levels of TXNIP， NLRP3， ASC， Caspase-1， Caspase-1 p20， GSDMD， GSDMD-N， IL-1β， and IL-18 in lung tissue were significantly elevated （P0.01）， and serum IL-1β and IL-18 levels also increased significantly （P0.01）. Compared with the model group， each medication group showed alleviation of qi deficiency symptoms and improved lung function （P0.01）. Pulmonary emphysema and inflammatory cell infiltration were reduced. Inflammatory cell levels decreased （P0.05）. The number of TUNEL-positive cells decreased significantly （P0.01）. Levels of LDH， ROS， and MDA decreased significantly （P0.05）， while GSH and SOD activities significantly increased （P0.01）. Morphological and structural damage in lung tissue was improved to varying degrees. Protein levels of TXNIP， NLRP3， ASC， Caspase-1， Caspase-1 p20， GSDMD， GSDMD-N， IL-1β， and IL-18 in lung tissue significantly decreased （P0.01）， and serum IL-1β and IL-18 levels also decreased significantly （P0.05）. ConclusionSQWF can improve lung function and alleviate inflammatory responses in COPD rats. Its mechanism may be related to regulating the ROS/TXNIP/NLRP3 pathway and inhibiting pyroptosis.

ObjectiveTo investigate the effects and underlying mechanisms of Shenqi Wenfei prescription （SQWF） on chronic obstructive pulmonary disease （COPD）. MethodsA rat model of COPD with lung Qi deficiency was established using lipopolysaccharide （LPS） combined with cigarette smoke. Forty-eight SD rats were randomly divided into a blank group， a model group， low-， medium-， and high-dose SQWF groups （2.835， 5.67， 11.34 g·kg^-1）， and a Yupingfeng group （1.35 g·kg^-1）. Drug administration began on day 29 after modeling and continued for 2 weeks. The general condition of the rats was observed， and the lung function in each group was assessed. Hematoxylin-eosin （HE） staining was used to observe pathological changes in lung tissue. The proportion of inflammatory cells in bronchoalveolar lavage fluid （BALF） was measured. Apoptosis in lung tissue was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL） staining. The release level of lactate dehydrogenase （LDH） in BALF was detected by a microplate assay. Reactive oxygen species （ROS） levels in lung tissue were detected using fluorescent probes. The levels of malondialdehyde （MDA）， total superoxide dismutase （SOD）， and reduced glutathione （GSH） in BALF were measured by biochemical methods. Ultrastructural changes in lung cells were observed via transmission electron microscopy. Double immunofluorescence staining was performed to detect the expression of thioredoxin-interacting protein （TXNIP） and nucleotide-binding oligomerization domain-like receptor protein 3 （NLRP3） in lung tissue. Western blot analysis was used to detect the protein expression of TXNIP， NLRP3， apoptosis-associated speck-like protein containing a CARD （ASC）， cysteinyl aspartate-specific protease-1 （Caspase-1）， Caspase-1 p20， gasdermin D （GSDMD）， GSDMD N-terminal active fragment （GSDMD-N）， interleukin-1β （IL-1β）， and IL-18 in lung tissue. Serum IL-1β and IL-18 levels were measured by ELISA. ResultsCompared with the blank group， the model group showed lassitude， fatigue， tachypnea， and audible phlegm sounds， and lung function significantly declined （P0.01）. Pulmonary emphysema and inflammatory cell infiltration were obvious. The level of inflammatory cells in BALF increased significantly （P0.05）. The number of TUNEL-positive cells increased （P0.01）. Levels of LDH， ROS， and MDA in BALF increased significantly （P0.01）， while GSH and SOD activities decreased significantly （P0.01）. Lung tissue cells showed irregular morphology， swollen mitochondria， disrupted cell membranes， and abundant vesicles， i.e.， pyroptotic bodies. Protein levels of TXNIP， NLRP3， ASC， Caspase-1， Caspase-1 p20， GSDMD， GSDMD-N， IL-1β， and IL-18 in lung tissue were significantly elevated （P0.01）， and serum IL-1β and IL-18 levels also increased significantly （P0.01）. Compared with the model group， each medication group showed alleviation of qi deficiency symptoms and improved lung function （P0.01）. Pulmonary emphysema and inflammatory cell infiltration were reduced. Inflammatory cell levels decreased （P0.05）. The number of TUNEL-positive cells decreased significantly （P0.01）. Levels of LDH， ROS， and MDA decreased significantly （P0.05）， while GSH and SOD activities significantly increased （P0.01）. Morphological and structural damage in lung tissue was improved to varying degrees. Protein levels of TXNIP， NLRP3， ASC， Caspase-1， Caspase-1 p20， GSDMD， GSDMD-N， IL-1β， and IL-18 in lung tissue significantly decreased （P0.01）， and serum IL-1β and IL-18 levels also decreased significantly （P0.05）. ConclusionSQWF can improve lung function and alleviate inflammatory responses in COPD rats. Its mechanism may be related to regulating the ROS/TXNIP/NLRP3 pathway and inhibiting pyroptosis.

This article systematically summarized the clinical experience of Professor Han Mingxiang,a national TCM master,in treating chronic obstructive pulmonary disease(COPD)from the perspective of the"qi monism"theory,proposing an innovative"three stages,three strategies"diagnostic and treatment approach.Under the guidance of"qi monism",Professor Han believes that the core pathological mechanisms of COPD progress are through three successive stages:dysfunction in the ascent and descent of qi,deficiency of yang qi,and prolapse of the great qi,all of which stem from the disruption of the dynamic balance of qi.In response to this chain of qi imbalance,Professor Han develops three strategies:"strengthening the foundation","illuminating the central yang",and"lifting and correcting",which aim to regulate qi flow,support yang qi,and coordinate the three energizers in a phased manner.This approach seeks to achieve dynamic restoration and holistic balance of qi,with prescriptions carefully aligned with the dynamic balance and pathological changes of qi,yielding distinctive therapeutic effects.

Objective To explore the mechanism of Pingchuanning Formula(PCN)for inhibiting airway inflammation in rats with asthmatic cold syndrome.Methods A total of 105 SD rats were randomized equally into 7 groups,including a control group,an asthmatic cold syndrome model group,3 PCN treatment groups at high,medium and low doses,a Guilong Kechuanning(GLCKN)treatment group,and a dexamethasone(DEX)treatment group.In all but the control rats,asthma cold syndrome models were established and daily gavage of saline,PCN,GLCKN or DEX was administered 29 days after the start of modeling.The changes in general condition,lung function and lung histopathology of the rats were observed,and inflammatory factors in the alveolar lavage fluid(BALF),oxidative stress,lung tissue ultrastructure,cytokine levels,and expressions of the genes related to the HMGB1/Beclin-1 axis and autophagy were analyzed.Results The rat models had obvious manifestations of asthmatic cold syndrome with significantly decreased body mass,food intake,and water intake,reduced FEV0.3,FVC,and FEV0.3/FVC,obvious inflammatory cell infiltration in the lung tissue,and increased alveolar inflammation score and counts of neutrophils,eosinophils,lymphocytes,macrophages,and leukocytes in the BALF.The rat models also had significantly increased MDA level and decreased SOD level and exhibited obvious ultrastructural changes in the lung tissues,where the expressions of HMGB1,Beclin-1,ATG5,TNF-α,IL-6,IL-1β,and IL-13 and the LC3II/I ratio were increased,while the levels of Bcl-2 and IFN-γ were decreased.PCN treatment significantly improved these pathological changes in the rat models,and its therapeutic effect was better than that of GLKCN and similar to that of DEX.Conclusion PCN can effectively alleviate airway inflammation in rat models of asthmatic cold syndrome possibly by modulating the HMGB1/Beclin-1 signaling axis to suppress cell autophagy,thereby attenuating airway inflammatory damages.

Objective To explore the mechanism of Shenqi Buzhong(SQBZ)Formula for alleviating mitochondrial dysfunction in a rat model of chronic obstructive pulmonary disease(COPD)in light of the AMPK/SIRT1/PGC-1α pathway.Methods Fifty male SD rat models of COPD,established by intratracheal lipopolysaccharide(LPS)instillation,exposure to cigarette smoke,and gavage of Senna leaf infusion,were randomized into 5 groups(n=10)for treatment with saline(model group),SQBZ Formula at low,moderate and high doses(3.08,6.16 and 12.32 g/kg,respectively),or aminophylline(0.024 g/kg)by gavage for 4 weeks,with another 10 untreated rats as the control group.Pulmonary function of the rats were tested,and pathologies and ultrastructural changes of the lung tissues were examined using HE staining and transmission electron microscopy.The levels of SOD,ATP,MDA,and mitochondrial membrane potential in the lungs were detected using WST-1,colorimetric assay,TBA,and JC-1 methods.Flow cytometry was used to analyze ROS level in the lung tissues,and the protein expression levels of P-AMPKα,AMPKα,SIRTI,and PGC-1α were detected using Western blotting.Results The rat models of COPD showed significantly decreased lung function,severe histopathological injuries of the lungs,decreased pulmonary levels of SOD activity,ATP and mitochondrial membrane potential,increased levels of MDA and ROS,and decreased pulmonary expressions of P-AMPKα,SIRTI,and PGC-1α proteins.All these changes were significantly alleviated by treatment with SQBZ Formula and aminophylline,and the efficacy was comparable between high-dose SQBZ Formula group and aminophylline group.Conclusion SQBZ Formula ameliorates mitochondrial dysfunction in COPD rats possibly by activating the AMPK/SIRT1/PGC-1α pathway.

Objective To investigate the therapeutic mechanism of Sangma Zhike Formula(SMZKF)for relieving cough sensitivity and airway inflammation in rats with postinfectious cough(PIC).Methods Male SD rat models were established by cigarette smoke exposure with intranasal LPS instillation and capsaicin aerosol inhalation.From day 19 following the start of PIC modeling,the rats received daily treatment with saline(model group),low-,medium-,and high-dose SMZKF,and compound methoxyphenamine(ASM)via gavage for 10 consecutive days(n=8).The assessments included behavioral changes,cough sensitivity(latency and frequency),lung histopathology,inflammatory cell counts and cytokine/mediator levels in the bronchoalveolar lavage fluid(BALF),oxidative stress markers in the lung tissue,and expressions of proteins related with cough hypersensitivity and pyroptosis.Results The rat models of PIC exhibited reduced mental alertness,accelerated respiration,and pronounced symptoms such as coughing,sneezing,and facial scratching with significantly shortened cough latency and increased 5-min cough frequency.Histopathological analysis revealed collapsed alveolar structures,thickened alveolar septa,and extensive inflammatory cell infiltration in the bronchi and peribronchial regions,accompanied by elevated bronchial and alveolar inflammation scores of the rat models.In the BALF,inflammatory cell counts and the levels of IL-1β,TNF-α,IL-6,COX-2,PGE-2,and TXA-2 were all markedly elevated,and the pulmonary oxidative stress markers(ROS and MDA)and myeloperoxidase(MPO)activity were also significantly increased.The pulmonary expressions of cough hypersensitivity-related proteins(TRPV1,SP,CGRP,and NK1R)and pyroptosis-associated markers(P-NF-κB,NLRP3,ACS,cleaved caspase-1,cleaved IL-1β,and GSDMD-N)were significantly upregulated in the model group.SMZKF interventions significantly ameliorated these pathological changes in the rat models,and high-dose SMZKF produced a similar therapeutic efficacy to that of ASM.Conclusion SMZKF alleviates cough sensitivity and airway inflammation in PIC rats possibly by inhibiting TRPV1-mediated SP/NK1R signaling and the NLRP3/caspase-1/GSDMD pyroptosis pathway.

ObjectiveTo investigate the improvement effect of Qibai Pingfei capsules on pulmonary vascular remodeling in rats at different stages of chronic obstructive pulmonary disease （COPD） and to analyze its possible mechanism of action. MethodsMale Sprague-Dawley （SD） rats were randomly divided into a normal group， an early COPD model group， an advanced COPD model group， an early-intervention high-dose group， a late-intervention high-dose group， an early-intervention low-dose group， a late-intervention low-dose group， an early-intervention pyrrolidine dithiocarbamate （PDTC） group， and a late-intervention PDTC group， with 15 rats in each group. A rat model of early COPD was constructed by using cigarette smoke combined with airway infusion using lipopolysaccharide（LPS）， and a rat model of advanced COPD was constructed by using airway infusion with LPS， cigarette smoke， and hypoxia. All groups except the normal group were given LPS airway drops on days 1 and 14 of the experiment， smoked for 1 h per day， and administered the drug once a day for 40 weeks from day 15 onward. In the high- and low-dose groups， rats were given 1 g·kg^-1 and 250 mg·kg^-1 Qibai Pingfei capsules， respectively by gavage， and in PDTC groups， rats were given 100 mg·kg^-1 of PDTC by intraperitoneal injection. The advanced COPD model group underwent 6 h of hypoxia per day in weeks 5-6. Lung function and mean pulmonary artery pressure were tested in rats. Morphologic changes in lung tissues were detected by hematoxylin-eosin（HE）staining. Collagen deposition in lung tissues was examined by Masson staining， and the levels of inflammatory factors including interleukin-1β（IL-1β）， interleukin-6（IL-6）， and tumor necrosis factor-α（TNF-α）in lung tissues were detected by enzyme-linked immunosorbent assay （ELISA）. The number of inflammatory cells in the alveolar lavage fluid of rats in each group was detected by Giemsa staining， and the protein expression of Toll-like receptor 4（TLR4）， myeloid differentiation factor 88（MyD88）， nuclear factor-κB（NF-κB）， TNF-α， vascular endothelial-cadherin（VE-cadherin）， α-smooth muscle actin（α-SMA）， and platelet endothelial cell adhesion molecule-1（CD31） was detected by Western blot in the lung tissues of rats. ResultsCompared with the normal group， the model group showed significantly decreased forced expiratory volume in 0.3 s （FEV_0.3）， forced vital capacity （FVC）， and FEV_0.3/FVC ratio related to lung function （P<0.05）， thickening of pulmonary vasculature， increased collagen deposition in the lungs， and enhanced mean pulmonary arterial pressure and expression levels of IL-6， IL-1β， and TNF-α （P<0.05）. Additionally， the model group also exhibited increased numbers of macrophages， lymphocytes， and neutrophils （P<0.05）， significantly higher protein expression of TLR4， MyD88， NF-κB， TNF-α， and α-SMA （P<0.05）， and significantly lower protein expression of VE-cadherin and CD31 （P<0.05）. Lung function was significantly improved in the Qibai Pingfei capsules groups compared with the model group （P<0.05）， with mean pulmonary arterial pressure reduced and pulmonary vascular thickening and collagen deposition in the lungs ameliorated. The Qibai Pingfei capsules groups also showed reduced expression levels of IL-6， IL-1β， and TNF-α （P<0.05） and decreased numbers of macrophages， lymphocytes， and neutrophils （P<0.05）， as well as reduced protein expression of TLR4， MyD88， NF-κB， TNF-α， and α-SMA （P<0.05） and elevated protein expression of VE-cadherin and CD31 （P<0.05） in rat lung tissues. ConclusionQibai Pingfei capsules inhibits inflammatory response and endothelial-to-mesenchymal transition probably by regulating the TLR4/NF-κB signaling pathway， thus improving pulmonary vascular remodeling in COPD model rats and showing therapeutic effects in the early stage of COPD.

This paper summarizes Professor HAN Mingxiang's clinical experience in treating chronic obstructive pulmonary disease （COPD）. He believes that the key pathomechanism of COPD in the acute exacerbation stage is the invasion of external pathogens triggering latent illness， while lung qi deficiency is the primary mechanism in the stable stage. The core pathological factors throughout disease progression are deficiency， phlegm， and blood stasis. Treatment emphasizes a staged and syndrome-based approach. During the acute exacerbation stage， for wind-cold invading the lung syndrome， the self-formulated Sanzi Wenfei Decoction （三子温肺汤） is used to relieve the exterior， dispel cold， warm the lung， and resolve phlegm. For phlegm-dampness obstructing the lung syndrome， Huatan Jiangqi Fomulation （化痰降气方） is prescribed to warm the lung， transform phlegm， descend qi， and calm wheezing. For phlegm-heat obstructing the lung syndrome， Qingfei Huatan Fomulation （清肺化痰方） is applied to clear heat， resolve phlegm， moisten the lung， and stop coughing. For phlegm and blood stasis interlocking syndrome， Qibai Pingfei Fomulation （芪白平肺方） is used to tonify qi， resolve phlegm， and activate blood circulation to remove stasis. During the stable stage， for lung qi deficiency syndrome， Shenqi Wenfei Decoction （参芪温肺汤） is employed to warm the lung， tonify qi， resolve phlegm， and eliminate turbidity. For lung-spleen qi deficiency syndrome， Shenqi Buzhong Decoction （参芪补中汤） is utilized to strengthen the spleen， tonify qi， and reinforce metal （lung） from earth （spleen）. For lung-kidney deficiency syndrome， Shenqi Tiaoshen Fomulation （参芪调肾方） is prescribed to tonify the lung， warm yang， and regulate kidney function to calm wheezing. These strategies provide insights into the traditional Chinese medicine treatment of COPD.

Time rhythm and the immune system play crucial roles in the pathogenesis of allergic rhinitis.Traditional Chinese medicine(TCM)believes that the circulation of qi and blood in lung meridian follows the principle of"yang during the day,yin at night",which has a defensive function to protect the body from external pathogens.Qi stagnation in lung meridian and impaired qi and blood circulation can lead to the invasion of external pathogens,exacerbating allergic reactions,especially during the active period of the lung meridian,when the immune system is most sensitive to allergens.Based on this,this paper proposes the concept of"bidirectional regulation among meridian,time rhythm,and immune system",and in combination with TCM theory of midnight-noon and ebb-flow doctrine,analyzes the fluctuations of allergic rhinitis symptoms and the temporal changes of meridian qi and blood,and reveals the rhythmic relationship between meridian activity and immune response.This paper combines existing clinical and experimental studies to support this hypothesis,integrating the time dimension into traditional TCM syndrome differentiation and treatment,offering a more individualized treatment approach.This concept not only provides novel scientific evidence for TCM treatment of allergic rhinitis,but also offers theoretical support for optimizing treatment timing and intervention strategies.