Mechanism of DaiTongXiao in the treatment of gouty arthritis through the NLRP3 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: DaiTongXiao (DTX) is a traditional Chinese Dai folk formulation utilized for gouty arthritis treatment, with substantial evidence supporting its anti-inflammatory properties. The NLRP3 inflammasome disorder is tightly linked to the development of many inflammatory diseases. AIM OF THE STUDY: To elucidate the therapeutic efficacy of DTX in gouty arthritis and reveal its potential underlying mechanism. MATERIALS AND METHODS: The primary active constituents in DTX were determined through ultraviolet spectrophotometry and gas chromatography. Rats underwent induction with monosodium urate (MSU), followed by treatment of J774A.1 cells with adenosine triphosphate (ATP) activation and lipopolysaccharide (LPS) induction and the subsequent culture in Dulbecco's modified Eagle's medium. The degree of foot joint swelling in rats was assessed, and ankle joints were evaluated through H&E staining. Enzyme-linked immunosorbent assay was performed to measure the levels of interleukin (IL)-1ß, IL-6, IL-8, and tumor necrosis factor (TNF)-α in both serum and cells. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to determine the relative mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 macrophages. The expression of NLRP3, ASC, Caspase-1, and NF-κB was examined by western blotting. RESULTS: DTX could alleviate MSU-induced joint swelling in rats, as evidenced by a reduction in joint inflammation. Moreover, DTX effectively enhanced the survival rate of J774A.1 cells following LPS induction and ATP activation. Furthermore, DTX significantly reduced IL-1ß, IL-6, IL-8, and TNF-α levels in both cell culture medium and rat serum. RT-PCR results revealed that DTX notably downregulated the mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 cells. Additionally, DTX downregulated NLRP3, ASC, NF-κB, and Caspase-1 expression in the joint tissue. CONCLUSIONS: DTX exerts a significant anti-gouty arthritis effect, with its mechanism being tightly linked to the NLRP3 inflammatory signaling pathway. This pathway may be modulated by inhibiting IL-1ß differentiation and maturation by downregulating NLRP3, ASC, Caspase-1, and NF-κB protein expression. This, in turn, leads to a reduction in the release of IL-6, IL-8, and TNF-α, ultimately impeding gouty arthritis progression.

Experimental study of the types of cavitation by air seeding using light microscopy.

Recently, three types of cavitation: (i) expanding gradually; (ii) expanding-exploding, becoming a long-shaped bubble-lengthening by degrees; (iii) suddenly exploding and fully filling the conduit instantly, were proposed. Directed by this theory, experiments were performed using light microscopy to study the natural drying processes of xylem sections of Platycladus orientalis (L.) Franco. Three different phenomena of gas filling process in conduits were captured by replaying recorded videos. The first phenomenon is that a bubble emerging in a conduit expands and elongates gradually to fill the conduit. The second phenomenon is that a bubble emerging in a conduit expands gradually, and then suddenly becomes long-shaped, and extends continuously. The third phenomenon is that a bubble instantly fully fills a conduit. This paper suggests in these experiments that after losing the bulk water of a section, as the water stress of that section became more severe, the water pressures of different conduits of the section were not necessarily the same, and as time went on, the water pressures decreased constantly. Considering some practical factors, the three phenomena captured in our experiment are explained by our theory.

Three types of cavitation caused by air seeding.

There are different opinions of the dynamics of an air bubble entering a xylem conduit. In this paper, we present a thorough mechanical analysis and conclude that there are three types of cavitation caused by air seeding. After an air seed enters a conduit at high xylem pressure P'(1), along with the drop of the water potential, it will expand gradually to a long-shaped bubble and extend continually. This is the first type of air seeding, or the type of expanding gradually. When the xylem pressure is moderate, right after an air seed enters a conduit, it will expand first. Then, as soon as the pressure reaches a threshold the bubble will blow up to form a bubble in long shape, accompanied by acoustic (or ultra-acoustic) emission. It will extend further as xylem pressure decreases continually. This is the second type of air seeding, or the type of expanding-exploding, becoming a long-shaped bubble-lengthening by degrees. In the range of P'(1) ≤ - 3P(o) (P(o) is atmospheric pressure), soon after an air seed is sucked into a conduit it will explode immediately and the conduit will be full of the gas of the bubble instantly. This is the third type of air seeding, or the type of sudden exploding and filling conduit instantly. The third type is the frequent event in daily life of plant.

A careful physical analysis of gas bubble dynamics in xylem.

Many studies have confirmed that cavitation in xylem is caused by air bubbles. Recently Shen et al. (Tree Physiol. 22 (2002) R655), analysed the expansion of a pre-existent bubble in xylem and one formed by air seeding. The present paper makes a further analysis of bubble expansion by the equilibrium criterion of the Helmholtz function. It has been proved that when xylem pressure P'l decreases to a special value P'l* from a value higher than, or equal to, or lower than -Po (Po is atmospheric pressure), an air bubble in xylem can grow up steadily, corresponding to minimums of the Helmholtz function F(r). As soon as P'l is lower than P'l*, since F(r) will be a decreasing function when P'l < P'l*, resulting in non-equilibrium of the bubble, it will break inducing a cavitation event. The analysis is consistent with the results of mechanism. Given P'l > or = -3Po, if an air bubble could enter a conduit, it would be in a stable equilibrium. When P'l < -3Po an air bubble entering a conduit will be in an unstable equilibrium. As the water further vaporizes, it will break at once. This is the case to which the former published formula P'l = -2sigma/rp is applicable.

Thermodynymic analysis of the mechanism of deep supercooling of tissue water in winter-hardy plants.

The temperature at which ice grows through narrow, hydrophilic capillary is known to be depressed. Further, the nucleation temperature near a hydrophilic surface varies with the size, geometry and the properties of a particle. In this paper we show how these two effects are additive for the water that freezes on the wall of a capillary without the presence of pre-existing ice. The combined effect is a substantial lowering of nucleation temperature that could, if this analysis is correct, have important cryobiological consequences.

Physical analysis of the process of cavitation in xylem sap.

Recent studies have confirmed that cavitation in xylem is caused by air bubbles. We analyzed expansion of a preexistent bubble adhering to a crack in a conduit wall and a bubble formed by the passage of air through a pore of a pit membrane, a process known as air seeding. We consider that there are two equilibrium states for a very small air bubble in the xylem: one is temporarily stable with a bubble radius r1 at point s1 on the curve P(r) relating pressure within the bubble (P) with bubble radius (r); the other is unstable with a bubble radius r2 at point s2 on Pr (where r1 < r2). In each equilibrium state, the bubble collapse pressure (2sigma/r, where sigma is surface tension of water) is balanced by the pressure difference across its surface. In the case of a bubble from a crack in a conduit wall, which is initially at point s1, expansion will occur steadily as water potential decreases. The bubble will burst only if the xylem pressure drops below a threshold value. A formula giving the threshold pressure for bubble bursting is proposed. In the case of an air seed entering a xylem conduit through a pore in a pit membrane, its initial radius may be r2 (i.e., the radius of the pore by which the air seed entered the vessel) at point s2 on Pr. Because the bubble is in an unstable equilibrium when entering the conduit, it can either expand or contract to point s1. As water vaporizes into the air bubble at s2, P rises until it exceeds the gas pressure that keeps the bubble in equilibrium, at which point the bubble will burst and induce a cavitation event in accordance with the air-seeding hypothesis. However, other possible perturbations could make the air-seeded bubble contract to s1, in which case the bubble will burst at a threshold pressure proposed for a bubble expanding from a crack in a conduit wall. For this reason some cavitation events may take place at a xylem threshold pressure (Pl'*) other than that determined by the formula, Plp'* = -2sigma/rp, proposed by Sperry and Tyree (1988), which is applicable only to air-seeded bubbles at s2. The more general formula we propose for calculating the threshold pressure for bubble breaking is consistent with the results of published experiments.