Analgesic nephropathy in Fischer 344 rats: comparative effects of chronic treatment with either aspirin or paracetamol.

This study has compared the relative nephrotoxicity of chronic treatment with aspirin or paracetamol in an animal model. Changes in renal structure and urinary concentrating ability were examined in female Fischer 344 rats after continuous treatment with either aspirin (120-230 mg/kg body wt/day), or paracetamol (140-210 mg/kg body wt/day), and were compared with age-matched untreated control rats. Renal morphological changes were examined after 40-83 weeks of analgesic treatment, using light and electron microscopy. Aspirin caused renal papillary necrosis and a decrease in urinary concentrating ability, whereas paracetamol alone did not cause significant renal damage. Aspirin produced damage to the interstitial cells and matrix, particularly in the mid-papillary region, followed by changes to the thin limbs of the loop of Henle and medullary capillary endothelium. These structural changes were similar to those described previously, when continuous treatment with combined aspirin and paracetamol was studied in the same animal model.     

Irreversible damage to the medullary interstitium in experimental analgesic nephropathy in F344 rats

Renal papillary necrosis (RPN) and a decreased urinary concentrating ability developed during continuous long-term treatment with aspirin and paracetamol in female Fischer 344 rats. Renal structure and concentrating ability were examined after a recovery period of up to 18 weeks, when no analgesics were given, to investigate whether the analgesic-induced changes were reversible. There was no evidence of repair to the damaged medullary interstitial matrix, or proliferation of remaining undamaged type 1 medullary interstitial cells after the recovery period following analgesic treatment. The recovery of urinary concentrating ability was related to the length of analgesic treatment and the extent of the resulting inner medullary structural damage. During the early stages of analgesic treatment, the changes in urinary concentrating ability were reversible, but after prolonged analgesic treatment, maximum urinary concentrating ability failed to recover. This study shows that prolonged analgesic treatment in Fischer 344 rats causes progressive and irreversible damage to the interstitial matrix and type 1 interstitial cells leading to RPN. The associated urinary concentrating defect is reversible only during the early stages of structural damage to the inner medulla.     

Lesions of the renal papilla induced by paracetamol

The acute nephrotoxic effects of paracetamol in the uninephrectomized homozygous Gunn rat are different from those of aspirin. Both compounds induce renal papillary necrosis but paracetamol produces accumulation of non-cellular material in the interstitial space, less damage to interstitial cells, more damage to tubular epithelium, and more severe necrosis of proximal convoluted tubules. In both cortex and papilla only a small fraction of the cells at risk are affected. It is concluded that the findings are consistent with a synergistic nephrotoxic effect between the two compounds, but that the lesions are not sufficiently severe for the natural history of analgesic nephropathy to be wholly explicable by such synergism.     

Early pathophysiological features in canine renal papillary necrosis induced by nefiracetam

To ascertain the early pathophysiological features in canine renal papillary necrosis (RPN) caused by the neurotransmission enhancer nefiracetam, male beagle dogs were orally administered nefiracetam at 300 mg/kg/day for 4 to 7 weeks in comparison with ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), at 50 mg/kg/day for 5 weeks. During the dosing period, the animals were periodically subjected to laboratory tests, light-microscopic, immunohistochemical, and electron-microscopic examinations and/or cyclooxygenase (COX)-2 mRNA analysis. In laboratory tests, a decrease in urinary osmotic pressure and increases in urine volume and urinary lactate dehydrogenase (LDH) level were early biomarkers for detecting RPN. Light-microscopically, nefiracetam revealed epithelial swelling and degeneration in the papillary ducts in week 7, while ibuprofen displayed degeneration and necrosis in the papillary interstitium in week 5. In immunohistochemical staining with COX-2 antibody, nefiracetam elicited a positive reaction within interstitial cells around the affected epithelial cells in the papillary ducts (upper papilla) in week 7, and ibuprofen positively reacted within interstitial cells adjacent to the degenerative and/or necrotic lesions in week 5. Ultrastructurally, nefiracetam exhibited reductions of intracellular interdigitation and infoldings of epithelial cells in the papillary ducts, whereas ibuprofen showed no changes in the identical portions. Thus, the early morphological change in the papilla brought about by nefiracetam was quite different from that elicited by ibuprofen. By the renal papillary COX-2 mRNA expression analysis, nefiracetam exceedingly decreased its expression in week 4, but markedly increased it in week 7, suggesting an induction of COX-2 mRNA by renal papillary lesions. These results demonstrate that the epithelial cell in the papillary ducts is the primary target site for the onset of RPN evoked by nefiracetam.     

Evaluation of analgesic efficacy,gastrotoxicity and nephrotoxicity of fixed-dose combinations of nonselective,preferential and selective cyclooxgenase inhibitors with paracetamol in rats

Nonsteroidal anti-inflammatory drugs (NSAIDs) are combined with paracetamol (PCM) with a view to enhance analgesic efficacy and reduce gastric toxicity. However, there are reports of enhanced nephrotoxicity with nonselective NSAID with PCM combinations. The present study investigated the analgesic efficacy, gastrotoxicity and nephrotoxicity of nonselective, preferential and selective cyclooxgenase inhibitors and their combination with PCM in rats.Graded doses of ibuprofen, meloxicam and celecoxib alone and their combination with fixed dose of PCM were administered to the rats by gavage for 14 days. The results showed that PCM potentiated the analgesic effect of all three classes of NSAIDs significantly as evidenced by increase in tail-flick latency in radiant heat method. Dose-dependent gastromucosal damage was produced by all the drugs, which was augmented significantly with PCM in the form of decreased total carbohydrate/protein ratio of mucin and increased gastric ulcer index. It was further confirmed by histopathology of rat’s stomach. The renal histopathology was conducted to evaluate inflammation, tubular damage, papillary necrosis, and interstitial changes. Increased nephrotoxicity was observed with all NSAIDs in dose-dependent manner and in combination with PCM.Our study revealed the augmented analgesia as well as enhanced gastrotoxicity and nephrotoxicity with all three major NSAIDs classes when combined with PCM. These findings highlighted the need for large pharmacoepidemiological studies to evaluate the magnitude of gastrotoxicity and nephrotoxicity in population who are on long-term treatment with NSAID combinations.     

Renal cortical accumulation of hyaluronan in adult rats exposed neonatally to angiotensin-converting enzyme inhibition.

Neonatal inhibition of the renin-angiotensin system [angiotensin-converting enzyme (ACE) inhibition] in the rat results in long-term abnormal renal morphology and function, including interstitial inflammation and fibrosis. Hyaluronan (hyaluronic acid, HA) has pathological implications in inflammatory diseases and renal ischaemia-reperfusion injury. The present study aimed at determining if renal cortical HA in the adult rat is correlated to the abnormal morphology and function in rats treated neonatally with the ACE inhibitor enalapril. In adult control rats (23 weeks old), the cortical HA content was very low [about 5 microg g(-1) dry weight (d.w.)] and about 1% of the papillary HA content. In rats treated neonatally with enalapril (days 3-13), the cortical HA level was 15 times that in control rats already at 21 days after birth, and it persisted at this level during adulthood (at 23 weeks). At 13 weeks the enalapril-treated animals showed markedly reduced ability (-53%) to concentrate urine during 24-h thirst provocation. At 21 days as well as at 23 weeks the enalapril-treated kidneys displayed morphological changes, such as papillary atrophy, dilation of the tubules and cellular infiltration of the cortical tissue. Histochemical staining confirmed the HA quantification assay and revealed a patchy staining for HA located in the same regions as the infiltrating cells. In conclusion, neonatal treatment with the ACE inhibitor enalapril results in renal morphological and functional abnormalities during adulthood. Cortical HA levels are already seriously elevated at day 21 and coexist with infiltrating cells. Besides the known effects of angiotensin II in development, the accumulation of HA in these kidneys may be involved in the genesis of at least the cortical abnormalities in enalapril-treated animals because of the proinflammatory effects and water-binding properties of HA.     

The induction of renal papillary necrosis in Gunn rats by analgesics and analgesic mixtures.

Homozygous members of the mutant Gunn strain of Wistar rats genetically lack the enzyme uridine diphosphate glucuronyl transferase. "High" and "low" dose gavage feeding for 18-34 days of an analgesic mixture containing aspirin, phenacetin and caffeine (APC) confirmed the previously reported susceptibility of these animals to analgesic induced renal papillary necrosis. Heterozygotes do not share the gross enzyme deficiency of homozygotes and, when treated with APC under identical conditions, failed to develop renal papillary necrosis. Groups of homozygotes were dosed by gavage with aspirin, phenacetin and paracetamol for 4 weeks. Renal papillary necrosis was produced by all 3 drugs, the lowest frequency of lesions occurring with phenacetin. It is postulated that the enzyme deficiency of homozygous Gunn rats influences the metabolism of analgesics to favour the excretion of nephrotoxic metabolites. The renal papillary necrosis appearing in these experiments is essentially an acute lesion, differing both in natural history and morphology from the renal papillary necrosis of analgesic nephropathy, suggesting that the pathogeneses of the experimental and human lesions differ.     

Protective effects of Chlorpromazine and Verapamil against cadmium-induced kidney damage in vivo

Overexposure to cadmium (Cd) can induce kidney damage, which was related to the oxidative damage and disturb intracellular Ca²⁺ homeostasis. Chlorpromazine (CPZ), targeting calmodulin (CaM), and the Ca²⁺ channel blocker Verapamil (Ver) are involved in intracellular Ca²⁺ homeostasis processes. The aim of the study was to investigate the kidney damage caused by Cd administrated for 6 weeks and to evaluate the effects of pre-treatment with either chlorpromazine or verapamil on Cd-induced kidney damage. Thirty-two Wistar rats were divided randomly into 4 groups by weight, i.e., control group, Cd-treated group, and CPZ or Ver pre-treated group. The Cd-treated group rats were subcutaneously (s.c.) injected with 7 μmol CdCl₂/kg body weight/day. The CPZ and Ver pre-treated group rats were intraperitoneally (i.p.) injected with 5 mg CPZ/kg body weight/day, 4 mg Ver/kg body weight/day, respectively, 1 h before the s.c. administration of 7 μmol CdCl₂/kg body weight/day. The control group rats were injected s.c. with saline at the same time. The volume of injection was 2 ml/kg body weight, 5 times per week, for up to 6 weeks. After 6 weeks, Cd concentrations in the renal cortex and urine were significantly higher in Cd-treated group than that in controls. Cd concentrations of the urine in CPZ and Ver pre-treated groups were significantly lower than that in Cd-treated group, but there were no significant changes in the renal cortex. Compared with the controls, urinary NAG, ALP activities, and the levels of GSH, MDA, and the activities of PKC, Na⁺–K⁺-ATPase, and Ca²⁺-ATPase in rats from the Cd-treated group were significantly increased. SOD activity was suppressed by Cd. Urinary NAG activity and the level of GSH and the activities of PKC and Ca²⁺-ATPase in both CPZ and Ver pre-treated groups were significantly lower than that in Cd-treated rats. The present results showed that Cd-induced kidney damage was related to the oxidative damage and disturb intracellular Ca²⁺ homeostasis. Both CPZ and Ver possess some ability to prevent cadmium-induced kidney damage via antioxidative action and by maintaining calcium homeostasis.     

Nephrotoxic tubular and interstitial lesions: morphology and classification

Nephrotoxic renal injury, and especially drug nephrotoxicity is now a common cause of acute renal failure. The most common patterns of renal injury produced by nephrotoxins, tubular damage, and interstitial nephritis, are discussed here. Toxic agents which are primarily tubular toxins include certain antibiotics, cisplatinum, anesthetics, and radiocontrast agents. In tubules injured by toxins, alterations range from subtle ultrastructural abnormalities to extensive tubular necrosis. Mechanisms of tubular injury include direct tubular cell toxicity, and alterations in intrarenal blood flow producing secondary tubular damage. Other commonly used therapeutic agents, including the penicillins, other antibiotics, and non-steroidal anti-inflammatory agents, produce renal dysfunction by inducing interstitial nephritis. Long-term analgesic abuse is associated with a particularly striking interstitial damage with frank papillary necrosis. Criteria for differentiating primary tubular injury with inflammation and primary interstitial nephritis with tubular injury are discussed. Individual commonly-used therapeutic agents are considered in some detail, with discussion of both clinical and morphological aspects of drug nephrotoxicity.     

Lipid emulsion reduces subacute toxicity of amphotericin B: a histopathological study.

In previous work acute toxic effects of amphotericin B (AB) were reduced in both in vitro and in vivo tests when AB was associated with a triglyceride-rich emulsion (AB-emulsion). The present paper compares the severity of the histopathological alterations as determined by morphometry produced in the target tissues (kidneys, liver, and lungs) by AB-emulsion with those produced by the conventional formulation AB-deoxycholate (DOC) following subacute AB treatment. No morphological alterations were seen in the spleen and heart following both AB-DOC and AB-emulsion treatment. Although the alterations in the liver, kidneys and lungs are basically the same for both formulations, the intensity of the changes varies considerably. AB-emulsion always caused statistically decreased severity of morphologic alterations, compared to AB-DOC by stereological measurements, for the three treatment regimes of AB-administration. These three treatment regimens consisted of 1 mg AB/kg of body weight every 48 hours for 20 days, 2 mg AB/kg of body weight every 48 hours for 12 days, and 2 mg AB/kg of body weight for 4 consecutive days. Thus, these regimens consisted of total doses varying from 8-12 mg/kg of body weight. Specifically, these morphological changes included proximal and distal tubular edema, inflammation and tubular cell degeneration in the kidney and a moderate inflammation of the portal region in the liver. Vacuolization of hepatocytes only occurred for AB-DOC treatment. In addition, acute interstitial inflammation was observed in the lungs prior to interstitial and alveolar edema. The intensity of the histopathological damage increase with the dose and with the reduction in the time interval between AB administrations. Abnormal serum biochemical parameters were observed for serum urea which was higher for both treated AB-groups, as compared to control, and for iron which was lower for the AB-DOC group. In conclusion, the decreased severity of the morphological alterations in the kidneys, liver, and lungs following subacute treatment with AB-emulsion, as compared to AB-DOC formulation, confirms our previous results consisting of acute toxic effects induced by in vitro and in vivo tests with AB-emulsion treatment.     

骨调素和巨噬细胞集落刺激因子在糖尿病大鼠肾组织中的表达及霉酚酸酯的干预作用

目的： 研究骨调素(OPN)和巨噬细胞集落刺激因子（M-CSF)在糖尿病大鼠肾组织中的表达及免疫抑制剂霉酚酸酯（MMF）的干预作用，旨在探讨MMF对糖尿病肾病(DN)的保护作用及机制。方法: Wistar大鼠行右肾切除术2周后,随机分为右肾切除对照组(NC)、糖尿病组(DM)、霉酚酸酯治疗组(DM+MMF)。腹腔注射链脲佐菌素(STZ,65 mg/kg ) 诱发糖尿病模型,MMF15 mg·kg^-1·d^-1灌胃。检测各组8周末的左肾重/体重比值、24 h尿蛋白（Upro）、血糖(BG) 、血肌酐( Scr)，观察肾脏形态学变化，免疫组化检测肾组织中OPN、M-CSF及CD68表达，荧光实时定量PCR测定肾组织中OPN mRNA表达。结果: 与对照组相比，DM组大鼠血糖、Upro、肾重/体重比值均显著上升(P<0.01);肾间质纤维化面积扩大(P<0.01);肾组织内OPN、M-CSF、CD68表达及OPN mRNA的表达均显著上调(P<0.01)。MMF干预后，上述指标除血糖外均被明显抑制(P<0.05或P<0.01)。结论: MMF减少糖尿病大鼠肾组织中OPN、M-CSF、CD68及OPN mRNA的表达，降低蛋白尿，预防肾损伤。MMF明显抑制DN肾小管－间质损害，可能与其抑制巨噬细胞的趋化与增殖有关。     

Mechanisms of impaired urinary concentrating ability in adult rats treated neonatally with enalapril

Neonatal angiotensin-converting enzyme inhibition or angiotensin II type-1 receptor blockade induces irreversible renal histological abnormalities and an impaired urinary concentrating ability in the rat. The aim of the present study was to determine the pathophysiological mechanisms underlying the defect in urine concentration in adult rats treated neonatally with enalapril. Male Wistar rats received daily intraperitoneal injections of enalapril (10 mg kg(-1)) or saline vehicle from 3 to 24 days of age. Assessments of fluid handling and maximal urine osmolality (Uosm(max)), renal function and tubular free water reabsorption (T(c)H2O) under pentobarbital anaesthesia, renal tissue solute concentrations, renal aquaporin-2 (AQP2) expression, and kidney histology, were performed in 12-16-week-old rats. Uosm(max) (1488 +/- 109 vs. 2858 +/- 116 mosm kg(-1), P < 0.05) and maximal T(c)H2O were reduced in enalapril- vs. vehicle-treated rats after administration of 1-desamino-8-D-arginine vasopressin. Neonatally enalapril-treated rats showed marked papillary atrophy, a decrease in medullary tissue solute concentrations, and a reduction in AQP2 expression specifically in the inner medulla. Glomerular filtration rate, renal plasma flow and urinary excretion rates of sodium, potassium and chloride did not differ between groups. In conclusion, adult rats treated neonatally with enalapril showed a urinary concentrating defect of renal origin which primarily could be explained by the papillary atrophy. However, an impaired ability to generate medullary interstitial hypertonicity, and a decrease in inner medullary AQP2 expression, also seem to contribute to this defect.     

2-Bromoethanamine nephrotoxicity in the nude mouse: an atypical targetting for the renal cortex

Male MF1-nu/nu/Ola/Hsd nude mice, maintained in a gnotobiotic environment, were dosed i.p. with either 50, 100 or 200 mg/kg 2-bromoethanamine (BEA) hydrobromide to induce a model papillary necrosis. Renal histological changes were examined in semithin glycolmethacrylate resin sections at 24, 48 and 72 h after BEA treatment. The sequence of medullary changes included pyknosis of interstitial cell nuclei, increased staining of the interstitial mucopolysaccharide matrix, platelets adhering to capillary endothelium, necrosis of collecting duct epithelial cells and denudation of the covering epithelium of the papilla. This was similar to that previously described in the Wistar rat, but the time course was extended. There was also a concomitant and extensive cortical necrosis of the P2 and P3 segments of the proximal tubule, which was evident prior to the onset of renal papillary necrosis at the higher doses of BEA. Nude mice show an atypical response to BEA compared to several mouse and rat strains, the hamster and pig, that suggests unique characteristics in this athymic murine mutant.     

Intratubular calcium phosphate deposition in acute analgesic nephropathy in rabbits.

Earlier chronic studies using both animal and human autopsy material have suggested that the initial lesion of analgesic nephropathy is papillary necrosis with secondary cortical interstitial nephritis. The present study was designed to define ultrastructural changes in renal tubules exposed to high levels of analgesics. Female New Zealand White rabbits were given 5-7 g APC and sacrificed after periods of 6 to 36 hours. As early as 6 hours after treatment, hydroxyapatite crystallite aggregates were seen impacted in Segment III (straight segment) of the proximal tubule at the cortico-medullary junction. Ultrastructural changes included selective calcification of the brush border, mitochondrial calcification, and peroxisomal changes. It was concluded, on the basis of ultrastructural changes, that calcification of altered tubular cells may be an initial event in analgesic nephropathy.     

Renal cortical accumulation of hyaluronan in adult rats exposed neonatally to angiotensin‐converting enzyme inhibition

Neonatal inhibition of the renin–angiotensin system [angiotensin‐converting enzyme (ACE) inhibition] in the rat results in long‐term abnormal renal morphology and function, including interstitial inflammation and fibrosis. Hyaluronan (hyaluronic acid, HA) has pathological implications in inflammatory diseases and renal ischaemia‐reperfusion injury. The present study aimed at determining if renal cortical HA in the adult rat is correlated to the abnormal morphology and function in rats treated neonatally with the ACE inhibitor enalapril. In adult control rats (23 weeks old), the cortical HA content was very low [about 5 μg g^–1 dry weight (d.w.)] and about 1% of the papillary HA content. In rats treated neonatally with enalapril (days 3–13), the cortical HA level was 15 times that in control rats already at 21 days after birth, and it persisted at this level during adulthood (at 23 weeks). At 13 weeks the enalapril‐treated animals showed markedly reduced ability (–53%) to concentrate urine during 24‐h thirst provocation. At 21 days as well as at 23 weeks the enalapril‐treated kidneys displayed morphological changes, such as papillary atrophy, dilation of the tubules and cellular infiltration of the cortical tissue. Histochemical staining confirmed the HA quantification assay and revealed a patchy staining for HA located in the same regions as the infiltrating cells. In conclusion, neonatal treatment with the ACE inhibitor enalapril results in renal morphological and functional abnormalities during adulthood. Cortical HA levels are already seriously elevated at day 21 and coexist with infiltrating cells. Besides the known effects of angiotensin II in development, the accumulation of HA in these kidneys may be involved in the genesis of at least the cortical abnormalities in enalapril‐treated animals because of the proinflammatory effects and water‐binding properties of HA.     

大黄蟅虫超微粉剂对大鼠肾间质纤维化的影响

目的比较大黄蟅虫传统丸剂与超微粉剂对肾间质纤维化大鼠模型的药效作用。方法实验动物分为假手术组、模型组、传统丸剂组（0．54g／kg／d）、超微粉剂组（0．27g／kg／d）4组。采用单侧输尿管结扎的方法复制大鼠肾间质纤维化模型,用大黄蟅虫传统丸剂与超微粉剂进行干预,观察不同剂型对肾间质纤维化大鼠肾功能指标、血清纤维化指标、病理组织变化的影响。结果与假手术组相比,模型组血清肌酐（Cr）、尿素氮（Urea）、透明质酸（HA）、层黏蛋白（LN）、Ⅳ型胶原（IV—C）、Ⅲ型前胶原（PCⅢ）显著升高（P〈0．01）,肾间质纤维化明显。与模型组相比,大黄蟅虫传统丸剂组与超微粉剂组血清Cr、Urea、HA、LN、PCⅢ、Ⅳ—C降低（P〈0．01）,肾小管损害和肾间质纤维化程度减轻。与传统丸剂组相比,超微粉剂组血清Cr、Urea较低（P〈0．05）,其余指标差异无统计学意义。结论大黄蟅虫传统丸剂与超微粉剂对实验性肾间质纤维化都有较好的防治作用,能降低肾间质纤维化程度。改善肾功能;在改善肾功能方面,超微粉剂型优于传统丸剂型。复方“大黄蟅虫”药材超微粉碎后减少药量的同时有助于提高药效,有利于剂型现代化。     

Chronic renal lesions in the uninephrectomized Gunn rat after analgesic mixtures

Chronic cortical and medullary damage have been produced in uninephrectomized homozygous Gunn rats by single doses of the analgesics aspirin, paracetamol and phenazone, and by analgesic mixtures. The lesions are more severe than those of other experimental models of analgesic nephropathy, and the appearances of the cortical lesions suggest that they are ultimately due to the effects of papillary necrosis rather than to acute tubular necrosis observed in acute experiments with this model. The presence of an acute inflammatory reaction in both cortex and medulla in a number of animals one month after administration of analgesics indicates the possibility that the observed chronic renal damage may result from the intervention of additional complicating factors rather than from a single direct effect of analgesics.     

The possibility of scar formation due to intrarenal reflux in analgesic nephropathy

Summary Using an autopsy case of a 59-year-old man with analgesic nephropathy, papillary necrosis, and nephrolithiasis, it is shown that analgesic nephropathy may be complicated by damage resulting from intrarenal urine reflux. The morphologic alterations characteristic of intrarenal and/or pyelointerstitial reflux are caused by high intrapelvic pressure values during episodes of renal colic. Bacterially infected and possibly also sterile urine is then forced into the interstitium, directly within the papillary defect or indirectly via the tubular system after rupture of the tubule. The result is a severe interstitial process with inflammation, destruction, and scarring.     

Inner-medullary organic osmolytes and inorganic electrolytes in K depletion

The renal concentrating defect typical for chronic K depletion has been ascribed to malfunction of renomedullary cells caused by inadequate accumulation of organic osmolytes. A reduction in intracellular ionic strength, which is believed to influence decisively the accumulation of organic osmolytes, has been held responsible for insufficient osmolyte accumulation. To test this hypothesis, intra- and extracellular Na, Cl and K concentrations, the major determinants of ionic strength, were measured in the papilla by electron microprobe analysis and organic osmolytes (glycerophosphorylcholine, betaine, sorbitol, myo-inositol, free amino acids) in inner-medullary tissue by HPLC in antidiuretic rats kept on either a control (normal-K) or a K-deplete (low-K) diet and in euhydrated rats with free access to water and control diet. K depletion was associated with a reduced urine concentrating ability. Papillary interstitial ionic strength (sum of Na, Cl and K) in antidiuretic low-K rats was significantly reduced compared with antidiuretic normal-K rats (688+/-19 vs. 971+/-61 mmol/kg wet wt) but was similar to that in euhydrated normal-K rats (643+/-35 mmol/kg wet wt). The lower interstitial ionic strength in antidiuretic low-K and euhydrated normal-K rats was associated with a lower total content of organic osmolytes in the inner medulla (365+/-14 and 381+/-20, respectively, vs. 465+/-11 mmol/kg protein in antidiuretic normal-K rats). Intracellular ionic strength (sum of Na, Cl and K) of papillary collecting duct cells, however, was similar in antidiuretic normal-K and euhydrated normal-K rats (171+/-5 and 179+/-11 mmol/kg wet wt) but lower in antidiuretic low-K rats (138+/-9 mmol/kg wet wt). These results do not support the view that, in the steady state of osmotic adaptation of renomedullary cells in situ, intracellular ionic strength is the decisive factor for maintaining high levels of organic osmolytes. During chronic K depletion, reduced osmolyte accumulation by renomedullary cells may be the consequence, rather than the cause, of lower medullary interstitial tonicity.     

单侧输尿管梗阻肾间质纤维化模型大鼠与川芎嗪的干预

背景：肾间质纤维化与组织基质金属蛋白酶2和金属蛋白酶组织抑制因子2表达失衡有关。 目的：建立单侧输尿管梗阻肾纤维化模型,观察川芎嗪治疗后肾间质病理变化及肾组织组织基质金属蛋白酶2和金属蛋白酶组织抑制因子2的表达变化。 方法：24只雌性SD大鼠分为3组,除假手术组外,模型组及川芎嗪组均在无菌条件下行左侧输尿管结扎建立单侧输尿管梗阻模型,川芎嗪组于术前1 d开始灌胃给药,40 mg/(kg•d),1次/d,连续2周。术后14 d处死各组大鼠,留取梗阻侧肾组织行苏木精-伊红染色和Masson染色以观察肾组织病理改变,免疫组化和反转录-聚合酶链反应方法检测肾组织基质金属蛋白酶2、金属蛋白酶组织抑制因子2的表达水平。 结果与结论：川芎嗪组可明显减轻肾小管的扩张和萎缩,减轻肾间质纤维组织增生及炎性细胞浸润。与假手术组相比,模型组基质金属蛋白酶2、金属蛋白酶组织抑制因子2蛋白和mRNA基因表达均明显增加(P < 0.01);川芎嗪组上述物质表达较模型组明显减少(P < 0.01)。提示川芎嗪通过下调基质金属蛋白酶2、金属蛋白酶组织抑制因子2的表达,从而改善单侧输尿管梗阻大鼠的肾间质纤维化。