Xiaochaihutang attenuates liver fibrosis in rats through activation of Nrf2 pathway

OBJECTIVE Oxidative sress is one of the key factor responsible for occurrence and development of hepatic fibrosis,a common consequence of chronic liver injury of multiple etiology.Nuclear factor erythroid 2-related factor 2(Nrf2)serves as a major regulator of a celular defense system against oxidative stress.Xiaochaihutang(XCHT),a compound of seven botanical extracts used for liver diseases traditionally in East Asia.However,few studies have investigated its anti-hepatic fibrosis effects and pathophysiological mechanism of action.The present study was designed to confirm the anti-hepatic fibrosis effects and explore its potential mechanism of action by investigating the intervention of Nrf2 pathway.METHODS Liver fibrosis was induced by repeated injection of Carbon tetrachloride(CCl4) over a period of 9 weeks.Starting from the 6 th week,the animals in treatment groups were given the appropriate dose of XCHT granules and silybin.Biochemical parameters,histological changes of the liver and alpha-smooth muscle actin(α-SMA) were determined.The expressions of Nrf2,Keap1,Nqo1,HO-1,Gclc and Gclm were assessed by RT-PCR and Western blot.RESULTS CCl4 caused a significant fibrosis damage in the rat liver and the liver functions and fibrosis degree were significantly improved by XCHT(5 g·kg^(-1) and 10 g·kg^(-1)).XCHT(5 g·kg^(-1) and 10 g·kg^(-1)) treatment significantly decreased the number of cells labeled with α-SMA antibodies.Moreover,XCHT(5 g·kg^(-1) and 10 g·kg^(-1))significantly increase Nqo1,HO-1,Gclc and Gclm expressions in the liver.CONCLUSION T hese studies establish XCHT is a potentially useful therapeutic agent for treatment of hepatic fibrosis and it might be via regulation of Nrf2 pathway in rats against oxidative stress,making further efforts to inhibiting the activated HSCs.Activation or up-regulation of Nrf2 pathway may be an alternative treatment strategy for liver fibrosis.

An improved arctangent algorithm based on phase-locked loop for heterodyne detection system

We present an ameliorated arctangent algorithm based on phase-locked loop for digital Doppler signal processing,utilized within the heterodyne detection system. We define the error gain factor given by the approximation of Taylor expansion by means of a comparison of the measured values and true values. Exact expressions are derived for the amplitude error of two in-phase & quadrature signals and the frequency error of the acousto-optic modulator. Numerical simulation results and experimental results make it clear that the dynamic instability of the intermediate frequency signals leads to cumulative errors, which will spiral upward. An improved arctangent algorithm for the heterodyne detection is proposed to eliminate the cumulative errors and harmonic components. Depending on the narrow-band filter, our experiments were performed to realize the detectable displacement of 20 nm at a detection distance of 20 m. The aim of this paper is the demonstration of the optimized arctangent algorithm as a powerful approach to the demodulation algorithm, which will advance the signal-to-noise ratio and measurement accuracy of the heterodyne detection system.