Preparation, optimization and in vitro-in vivo evaluation of Shunxin sustained release granules

Toward chronopharmaceutical drug delivery patches and biomaterial coatings for the facilitation of wound healing

Implantation of a biomaterial entails a form of injury where the integration of the implant into the host tissue greatly depends on the proper healing of the wound. Wound healing, itself, consists of a number of physiological processes, each occurring within a characteristic time window. A composite, multilayered polymeric drug delivery carrier for adhesion to the wound site and its supply with molecules released at precise time windows at which the stages in the healing process that they target occur is conceptualized here. We also present a simplified version of one such multilayered composite fabricated by a combination of solvent casting and dip coating, comprising the base poly(ε-caprolactone) layer reinforced with hydroxyapatite nanoparticles, poly(glutamic acid) mesolayer and poly-l-lysine surface layer, each loaded with specific small molecules and released at moderately distinct timescales, partially matching the chronology of wound healing. To that end, the base layer proved suitable for the delivery of an anti-inflammatory molecule or an angiogenic agent, the mesolayer appeared appropriate for the delivery of an epithelialization promoter or a granulation factor, and the adhesive surface layer interfacing directly with the site of injury showed promise as a carrier of a vasodilator. The drug release mechanisms were diffusion-driven, suggesting that the drug/carrier interaction is a key determinant of the release kinetics, as important as the nature of the polymer and its hydrolytic degradation rate in the aqueous medium. Morphological and phase composition analyses were performed, along with the cell compatibility ones, demonstrating solid adhesion and proliferation of both transformed and primary fibroblasts on both surfaces of the composite films. The design of the multilayered composite drug delivery carriers presented here is prospective, but requires further upgrades to achieve the ideal of a perfect timing of the sequential drug release kinetics and a perfect resonance with the physiological processes defining the chronology of wound healing.

Shunxin decoction improves diastolic function in rats with heart failure with preserved ejection fraction induced by abdominal aorta constriction through cyclic guanosine monophosphate-dependent protein kinase Signaling Pathway

OBJECTIVE

To determine whether Shunxin decoction improves diastolic function in rats with heart failure with preserved ejection fraction (HFpEF) by regulating the cyclic guanosine monophosphate-dependent protein kinase (cGMP-PKG) signaling pathway.

METHODS

Except for control group 8 and sham surgery group 8, the remaining 32 male Sprague-Dawlay rats were developed into HFpEF rat models using the abdominal aorta constriction method. These rats in the HFpEF model were randomly divided into the model group, the Shunxin high-dose group, the Shunxin low-dose group, and the Qiliqiangxin capsule group. The three groups received high-dose Shunxin decoction, low-dose Shunxin decoction, and Qiliqiangxin capsule by gavage, respectively, for 14 d. After the intervention, the diastolic function of each rat was evaluated by testing E/A, heart index, hematoxylin-eosin staining, Masson, myocardial ultrastructure, and N-terminal pro-brain natriuretic peptide (NT-proBNP). The Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM) software was used to predict targets for which Shunxin decoction acts on the cGMP-PKG pathway. Natriuretic peptide receptor A (NPRA) and guanylate cyclase (GC) were detected by immunohistochemistry, and eNOS, phosphodiesterase 5A (PDE5A), and cGMP-dependent protein kinase 1(PKG I) were determined by Western blotting.

RESULTS

Compared to the model group, the thickness of the interventricular septum at the end of diastole (IVSd) and the thickness of the posterior wall at the end of diastole (PWd) of the Shunxin decoction high-dose group, Shunxin decoction low-dose group, and Qiliqiangxin capsule group were all significantly reduced ( < 0.01). Furthermore, Shunxin decoction high-dose group E/A value was decreased ( < 0.01). Compared to the model group, the expression of NPRA and GC increased in the Shunxin decoction low-dose group and the Qiliqiangxin capsule group ( < 0.01). Compared to the model group, the expressions of eNOS and PKG I increased ( < 0.05) in the Shunxin decoction high-dose group. The expression of PDE5A expression decreased in the myocardium of the Shunxin decoction high-dose group, Shunxin decoction low-dose group, and Qiliqiangxin capsule group compared to the model group ( < 0.01).

CONCLUSIONS

Shunxin decoction can improve diastolic function in rats with HFpEF. It increases the expression of NPRA, GC, and eNOS in the myocardial cell cGMP-PKG signaling pathway, upregulates cGMP expression, decreases PDE5A expression to reduce the cGMP degradation. Thus, the cGMP continually stimulates PKG I, reversing myocardial hypertrophy and improving myocardial compliance in HFpEF rats.