Worcester Elaine, Evan Andrew, Bledsoe Sharon, Lyon Mark, Chuang Mark, Orvieto Marcello, Gerber Glenn, Coe Fredric
Nephrology Section/MC 5100, Univ. of Chicago, 5841 South Maryland Ave., Chicago, IL 60637, USA.
Am J Physiol Renal Physiol. 2006 Nov;291(5):F1061-9. doi: 10.1152/ajprenal.00033.2006.
Rats with small bowel resection fed a high-oxalate diet develop extensive deposition of calcium oxalate (CaOx) and calcium phosphate crystals in the kidney after 4 mo. To explore the earliest sites of renal crystal deposition, rats received either small bowel resection or transection and were then fed either standard chow or a high-oxalate diet; perfusion-fixed renal tissue from five rats in each group was examined by light microscopy at 2, 4, 8, and 12 wk. Rats fed the high-oxalate diet developed birefringent microcrystals at the brush border of proximal tubule cells, with or without cell damage; the lesion was most common in rats with both resection and a high-oxalate diet (10/19 with the lesion) and was significantly correlated with urine oxalate excretion (P < 0.001). Rats with bowel resection fed normal chow had mild hyperoxaluria but high urine CaOx supersaturation; four of these rats developed birefringent crystal deposition with tubule plugging in inner medullary collecting ducts (IMCD). Two rats fed a high-oxalate diet also developed this lesion, which was correlated with CaOx supersaturation, but not oxalate excretion. Tissue was examined under oil immersion, and tiny birefringent crystals were noted on the apical surface of IMCD cells only in animals with IMCD crystal plugging. In one animal, IMCD crystals were both birefringent and nonbirefringent, suggesting a mix of CaOx and calcium phosphate. Overall, these animals demonstrate two distinct sites and mechanisms of renal crystal deposition and may help elucidate renal lesions seen in humans with enteric hyperoxaluria and stones.
接受小肠切除术后喂食高草酸盐饮食的大鼠在4个月后，肾脏中会出现大量草酸钙（CaOx）和磷酸钙晶体沉积。为了探究肾脏晶体沉积的最早部位，对大鼠进行小肠切除或横断手术，然后分别喂食标准饲料或高草酸盐饮食；每组五只大鼠的灌注固定肾脏组织在2周、4周、8周和12周时进行光学显微镜检查。喂食高草酸盐饮食的大鼠在近端小管细胞的刷状缘出现双折射微晶，伴有或不伴有细胞损伤；这种病变在同时进行切除手术并喂食高草酸盐饮食的大鼠中最为常见（10/19有此病变），且与尿草酸盐排泄显著相关（P < 0.001）。接受小肠切除手术并喂食正常饲料的大鼠有轻度高草酸尿症，但尿CaOx过饱和度高；其中四只大鼠在内髓集合管（IMCD）出现双折射晶体沉积并伴有小管堵塞。两只喂食高草酸盐饮食的大鼠也出现了这种病变，其与CaOx过饱和度相关，但与草酸盐排泄无关。在油镜下检查组织时，仅在有IMCD晶体堵塞的动物的IMCD细胞顶端表面发现微小的双折射晶体。在一只动物中，IMCD晶体既有双折射的也有非双折射的，提示存在CaOx和磷酸钙的混合物。总体而言，这些动物展示了肾脏晶体沉积的两个不同部位和机制，可能有助于阐明在患有肠道高草酸尿症和结石的人类中所见的肾脏病变。
