[Therapeutic effect of Heirong Kidney-Tonifying Granule on busulfan-induced dyszoospermia in model mice].

OBJECTIVE: To explore the therapeutic effect of Heirong Kidney-Tonifying Granule (HKTG) on busulfan-induced dyszoospermia in mice, and its mechanism in regulating testicular spermatogenesis. METHODS: Forty-eight male mice were randomly divided into six groups of an equal number: blank control (BC), negative control (NC), HKTG-1, HKTG-2, HKTG-3 and HKTG-4. The model of dyszoospermia was established in the latter five groups by intraperitoneal injection of busulfan at 40 mg/kg and, 30 days after modeling, the mice in the BC and NC groups were given gavage of normal saline, and those in the latter four groups treated with HKTG + pilose antler at 400 mg/kg/d, HKTG + pilose antler at 800 mg/kg/d, HKTG + black ants at 400 mg/kg/d and HKTG + black ants at 800 mg/kg/d, respectively, all for 5 consecutive weeks. The mean body weight of the mice was recorded daily, and their testes weighed after treatment. The microstructure of the testis tissue was detected by HE staining, and the localization and expression of spermatogenesis markers in the testis were determined by immunofluorescence staining. RESULTS: The mice in the BC and NC groups showed no statistically significant difference from those in the HKTG groups in the body weight and daily body weight gain (P > 0.05). Compared with the NC mice, the animals in the HKTG-1 group exhibited significantly increased testis weight (P < 0.05), and those in the HKTG-1 and HKTG-1 groups presented a large number of germ cells in the seminiferous tubules, including deformed sperm cells in the lumen, and some seminomatogonia in the seminogenic tubules, but almost no deformed sperm cells. The expressions of the total germ cell marker gene Ddx4, spermatogonial cell marker gene Dazl, spermatic cell marker gene Sycp3 and sperm cell marker gene Tnp1 were significantly upregulated (P < 0.05) while that of the Sertoli cell marker gene Sox9 downregulated (P < 0.05) in the HKTG-1 group. The number of Sertoli cells in the HKTG-1 group was remarkably reduced (P<0.05), corresponding to the increased number of germ cells in the HKTG-1 group. There were no significant changes in the relative expressions of the DDX4, Dazl, Sycp3 and Tnp1 genes, nor in the number of Sertoli cells in the HKTG-3 and HKTG-4 groups. The expressions of meiosis-related genes Meioc, Stra8 and Spo11were markedly upreguated in the HKTG-1 group, indicating significantly improved spermatogenesis in the testis tissue of the mice. CONCLUSION: HKTG improves the function of spermatogenic cells and increases sperm production in the testis tissue of mice by promoting meiosis.

The regioselective glucuronidation of morphine by dimerized human UGT2B7, 1A1, 1A9 and their allelic variants.

Uridine diphosphate-glucuronosyltransferase (UGT) 2B7 is expressed mostly in the human liver, lung and kidney and can transfer endogenous glucuronide group into its substrate and impact the pharmacological effects of several drugs such as estriol, AZT and morphine. UGT2B7 and its allelic variants can dimerize with the homologous enzymes UGT1A1 and UGT1A9, as well as their allelic variants, and then change their enzymatic activities in the process of substrate catalysis. The current study was designed to identify this mechanism using morphine as the substrate of UGT2B7. Single-recombinant allozymes, including UGT2B7*1 (wild type), UGT2B7*71S (A71S, 211G>T), UGT2B7*2 (H268Y, 802C>T), UGT2B7*5 (D398N, 1192G>A), and double-recombinant allozymes formed by the dimerization of UGT1A9*1 (wild type), UGT1A9*2 (C3Y, 8G>A), UGT1A9*3 (M33T, 98T>C), UGT1A9*5 (D256N, 766G>A), UGT1A1 (wild type) with its splice variant UGT1A1b were established and incubated with morphine in vitro. Each sample was analyzed with HPLC-MS/MS. All enzyme kinetic parameters were then measured and analyzed. From the results, the production ratio of its aberrant metabolism and subsequent metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), changes regioselectively. Double-recombinant allozymes exhibit stronger enzymatic activity catalyzing morphine than the single-recombinant alloyzymes. Compared to UGT2B7*1, UGT2B7*2 singles or doubles have lower Km values for M3G and M6G, whereas UGT2B7*5 allozymes perform opposite effects. The double allozymes of UGT1A9*2 or UGT1A9*5 with UGT2B7 tend to produce M6G. Interestingly, the majority of single or double allozymes significantly reduce the ratio of M3G to M6G. The UGT1A9*2-UGT2B7*1 double enzyme has the lowest M3G:M6G ratio, reflecting that more M6G would form in morphine glucuronide metabolism. This study demonstrates that UGT2B7 common SNPs and their dimers with UGT1A1 and UGT1A9 and their allelic variants can regioselectively affect the generation of two metabolites of morphine via altering the CLint ratios of M3G to M6G. These results may predict the effectiveness of morphine antinociception in individualized opioid treatment.

Brain-derived neurotrophic factor involved epigenetic repression of UGT2B7 in colorectal carcinoma: A mechanism to alter morphine glucuronidation in tumor.

Uridine diphosphate-glucuronosyltransferase (UGT) 2B7, as one of significant drug enzymes, is responsible on the glucuronidation of abundant endobiotics or xenobiotics. We here report that it is markedly repressed in the tumor tissues of colorectal carcinoma (CRC) patients. Accordingly, morphine in CRC cells will stimulate the expression of its main metabolic enzyme, UGT2B7 during tolerance generation by activating the positive signals in histone 3, especially for trimethylated lysine 27 (H3K4Me3) and acetylated lysine 4 (H3K27Ac). Further study reveals that brain-derived neutrophilic factor (BDNF), a secretory neurotrophin, enriched in CRC can interact and inhibit UGT2B7 by primarily blocking the positive signals of H3K4Me3 as well as activating H3K27Ac on the promoter region of UGT2B7. Meanwhile, BDNF repression attributes to the sensitizations of main core factors in poly-comb repressive complex (PRC) 1 rather than PRC2 as the reason of the depression of SUZ12 in the later complex. Besides that, the productions of two main morphine glucuronides are both increased in the BDNF deficient or TSA and BIX-01294 treated morphine tolerance-like HCT-116 cells. On the same condition, active metabolite, morphine-6-glucuronide (M6G) was accumulated more than inactive M3G. Our findings imply that enzymatic activity enhancement and substrate regioselective catalysis alteration of UGT2B7 may release morphine tolerance under the cure of tumor-induced pain.

siRNA capsulated brain-targeted nanoparticles specifically knock down OATP2B1 in mice: a mechanism for acute morphine tolerance suppression.

Regulating main brain-uptake transporter of morphine may restrict its tolerance generation, then modify its antinociception. In this study, more than 2 fold higher intracellular uptake concentrations for morphine and morphine-6-glucuronide (M6G) were observed in stable expression cells, HEK293-hOATP2B1 than HEK293-MOCK. Specifically, the Km value of morphine to OATP2B1 (57.58 ± 8.90 µM) is 1.4-time more than that of M6G (80.31 ± 21.75 µM); Cyclosporine A (CsA), an inhibitor of OATP2B1, can inhibit their intracellular accumulations with IC50 = 3.90 ± 0.50 µM for morphine and IC50 = 6.04 ± 0.86 µM for M6G, respectively. To further investigate the role of OATP2B1 in morphine brain transport and tolerance, the novel nanoparticles of DGL-PEG/dermorphin capsulated siRNA (OATP2B1) were applied to deliver siRNA into mouse brain. Along with OATP2B1 depressed, a main reduction was found for each of morphine or M6G in cerebrums or epencephalons of acute morphine tolerance mice. Furthermore, calcium/calmodulin-dependent protein kinase IIα (CaMKIIα) in mouse prefrontal cortex (mPFC) underwent dephosphorylation at Thr286. In conclusion, OATP2B1 downregulation in mouse brain can suppress tolerance via blocking morphine and M6G brain transport. These findings might help to improve the pharmacological effects of morphine.