OBJECTIVE： To optimize the proteolytic enzymes for enzymolysis technology of degreasing ointment from Periplaneta americana， and to improve the extraction rate and activity of anti-liver fibrosis active part from P. americana. METHODS： Using degreasing ointment of P. americana as control， ninhydrin method and folin-ciocalteu method were used to investigate the hydrolysis degree of trypsin （TR）， pepsin （PE）， alkaline protease （AL）， papain （PA） and neutral protease （NE） to the degreasing ointment. Macroporous resin isolation and purification method was used to investigate the yield of elution part from hydrolyzate， with 50％， 60％， 70％， 95％ ethanol as eluting solvents. Inhibition test in vitro of rat hepatic stellate cells HSC-T6 was performed， and anti-liver fibrosis activity of elution part from hydrolyzate was investigated. RESULTS： The hydrolysis degree of PA and NE were 14.15％ and 15.70％， showing strong enzymatic hydrolysis ability. The yield of 95％ ethanol elution part from PA， NE and AL hydrolyzate were （0.73±0.04）％，（0.65±0.01）％ and（0.64±0.05）％， improving 30.36％， 16.07％， 14.29％ compared with degreasing ointment without enzyme. Results of inhibition test in vitro showed that inhibitory rate of 50％， 60％， 70％ ethanol elution parts isolated and  purified from hydrolyzate had a low inhibition rate or a growth-promoting effect on HSC-T6 cells. Inhibition rates of 95％ ethanol elution parts to HSC-T6 cells were all more than 20％. IC50 of 95％ ethanol elution part isolated and purified from PA and NE hydrolyzate for 24-72 h were 94.5-112.3 and 117.1-120.0 μg/mL， which were lower than that （116.1-123.0 μg/mL） of degreasing ointment without enzyme. CONCLUSIONS： PA is the best hydrolyzate for enzymolysis technology of active parts against liver fibrosis in degreasing ointment from P. americana， followed by NE and AL； PE and TR， which have poor effect， are not suitable for the enzymatic hydrolysis technology.

Pure red cell aplasia (PRCA) is a well-recognized complication of ABO major mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT), with a reported incidence of 10%-20% (Zhidong et al., 2012; Busca et al., 2018). It is clinically characterized by anemia, reticulocytopenia, and the absence of erythroblasts in a normal-appearing bone marrow biopsy (Shahan and Hildebrandt, 2015). The mechanism for PRCA has been presumed to be persistence of recipient isoagglutinins, produced by residual host B lymphocytes or plasma cells, which can interfere with the engraftment of donor erythroid cells (Zhidong et al., 2012). Several risk factors of PRCA at presentation are known, such as presence of anti-A isoagglutinins before transplantation, reduced intensity conditioning, absence of acute graft-versus-host disease (GVHD), sibling donors, and cyclosporin A (CsA) as GVHD prophylaxis (Hirokawa et al., 2013). PRCA is not considered to be a barrier to HSCT, as some patients can recover spontaneously or benefit from various approaches including high-dose steroids, erythropoietin (EPO), plasma exchange, immunoadsorption, donor lymphocyte infusion (DLI), treatment with rituximab, bortezomib, or daratumumab, and tapering or discontinuation of immunosuppression (Hirokawa et al., 2013; Bathini et al., 2019). However, there are still some patients who fail to respond even to aggressive treatment; they become red cell transfusion-dependent and iron-overloaded, and their life quality is impaired.