目的测量常用实验动物内耳前庭感觉区的实际面积和量化分析前庭各个感觉区的毛细胞总数或密度。方法①制作CBA/CaJ小鼠、裸鼠、SD大鼠、豚鼠、南美栗鼠、新西兰白兔和非洲黑长尾猴的球囊斑铺片和椭圆囊斑铺片及壶腹嵴铺片,所有铺片样品...目的测量常用实验动物内耳前庭感觉区的实际面积和量化分析前庭各个感觉区的毛细胞总数或密度。方法①制作CBA/CaJ小鼠、裸鼠、SD大鼠、豚鼠、南美栗鼠、新西兰白兔和非洲黑长尾猴的球囊斑铺片和椭圆囊斑铺片及壶腹嵴铺片,所有铺片样品来自每种受试动物的6个颞骨,在放大100倍的光学显微镜下拍摄2个囊斑铺片的整体照片;②应用Image J软件的图像测量程序,测量了上述7种常用实验动物球囊斑和椭圆囊斑的实际面积;③用网格将球囊斑铺片和椭圆囊斑铺片照片上的前庭感觉区划分为一个个方块区域。在放大400倍的光学显微镜下准确计数每个方格内的毛细胞数量,然后将每个方格的毛细胞计数结果相加以获得每种受试动物球囊斑和椭圆囊斑上的毛细胞总数;④应用前庭小视野定量观察技术计算出前庭各个感觉区小视野范围内的毛细胞密度。结果①从小鼠、裸鼠、大鼠、豚鼠、南美栗鼠、白兔到猴的球囊斑面积依次为(0.193±0.009)、(0.216±0.008)、(0.323±0.010)、(0.528±0.035)、(0.687±0.065)、(1.237±0.075)、(1.371±0.032)mm 2;椭圆囊斑的面积依次为(0.193±0.020)、(0.208±0.013)、(0.321±0.011)、(0.526±0.034)、(0.795±0.017)、(1.224±0.082)、(1.388±0.048)mm 2;②从小鼠、裸鼠、大鼠、豚鼠、南美栗鼠、白兔到猴的球囊斑毛细胞的总数依次为(2476.3±64.4)、(2389.8±47.8)、(3135.3±191.6)、(4882.2±208.7)、(6128.5±242.9)、(10572.2±464.4)、(10992.7±397.4)个;椭圆囊斑毛细胞的总数依次为(2491.4±54.8)、(2368.0±46.1)、(3218.8±82.9)、(4925.3±271.1)、(7794.0±386.1)、(11347.4±435.7)、(11114.5±410.6)个;③从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的球囊斑微纹区和周边区的毛细胞密度(毛细胞数量/0.03 mm 2)依次为101.0±5.79(微纹区)/120.8±4.15(周边区),95.5±3.91(微纹区)/109.2±5.26(周边区),78.4±6.54(微纹区)/94.8±4.38(周边区),60.0±4.74(微纹区)/84.6±2.61(周边区),57.2±3.83(微纹区)/80.0±3.54(周边区),53.8±4.21(微纹区)/68.0±4.18(周边区)。从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的椭圆囊斑微纹区和周边区的毛细胞密度(毛细胞数量/0.03 mm 2)依次为103.8±5.02(微纹区)/119.2±3.70(周边区),91.2±2.49(微纹区)/106.4±4.16(周边区),74.1±3.54(微纹区)/90.8±3.56(周边区),60.4±4.98(微纹区)/81.6±2.07(周边区),57.8±1.92(微纹区)/77.8±3.70(周边区),54.0±2.74(微纹区)/66.4±2.51(周边区)。从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的壶腹嵴毛细胞密度(毛细胞数量/0.03 mm 2)依次为112.4±6.38,105.5±3.51,95.2±3.42,84.0±7.16,78.2±2.86,70.8±2.39。可见由于体型较小动物毛细胞的细胞体比体型较大动物毛细胞的细胞体小,因而体型较小动物的前庭毛细胞密度高于体型较大动物的前庭毛细胞密度。另外,每种实验动物球囊斑和椭圆囊斑微纹区的毛细胞密度相似,周边区的毛细胞密度也大致相同,但是同种实验动物囊斑微纹区的毛细胞密度却低于周边区的毛细胞密度。此外,壶腹嵴毛细胞的密度与球囊斑和椭圆囊斑周边区的毛细胞密度几乎相同。鉴于某些损害因素往往具有选择性破坏囊斑微纹区毛细胞的表现,因此囊斑微纹区的毛细胞密度应该与囊斑周边区的毛细胞密度区分开来进行统计,必要时甚至需要把Ⅰ型毛细胞和Ⅱ型毛细胞也区分开来分别予以病理学改变的定量评估。结论本研究采用的前庭测量方法和获得的前庭各个感觉区的测量数据和毛细胞总数及毛细胞密度,为前庭病理学研究的定量分析提供了有益的参考经验和必要的参考数据。展开更多
Carboplatin, a second-generation platinum chemotherapeutic drug, is considerably less ototoxic than cisplatin. While common laboratory species such as mice, guinea pigs and rats are highly resistant to carboplatin oto...Carboplatin, a second-generation platinum chemotherapeutic drug, is considerably less ototoxic than cisplatin. While common laboratory species such as mice, guinea pigs and rats are highly resistant to carboplatin ototoxicity, the chinchilla stands out as highly susceptible. Moreover, carboplatin causes an unusual gradient of cell death in chinchillas. Moderate doses selectively damage type I spiral ganglion neurons (SGN) and inner hair cells (IHC) and the lesion tends to be relatively uniform along the length of the cochlea. Higher doses eventually damage outer hair cells (OHC), but the lesion follows the traditional gradient in which damage is more severe in the base than the apex. While carboplatin ototoxicity has been well documented in adult animals in vivo, little is known about its in vitro toxicity. To elucidate the ototoxic effects of carboplatin in vitro, we prepared cochlear and vestibular organotypic cultures from postnatal day 3 rats and adult chinchillas. Chinchilla cochlear and vestibular cultures were treated with carboplatin concentrations ranging from 50 μM to 10 mM for 48 h. Consistent with in vivo data, carboplatin selectively damaged IHC at low concentrations (50-100 μM). Surprisingly, IHC loss decreased at higher doses and IHC were intact at doses exceeding 500 μM. The mechanisms underlying this nonlinear response are unclear but could be related to a decrease in carboplatin uptake via active transport mechanisms (e.g., copper). Unlike the cochlea, the carboplatin dose-response function increased with dose with the highest dose destroying all chinchilla vestibular hair cells. Cochlear hair cells and auditory nerve fibers in rat cochlear organotypic cultures were unaffected by carboplatin concentrations <10 μM; however, the damage in OHC were more severe than IHC once the dose reached 100 μM. A dose at 500 μM destroyed all the cochlear hair cells, but hair cell loss decreased at high concentrations and nearly all the cochlear hair cells were present at the highest dose, 5 mM. Unlike the nonlinear dose-response seen with cochlear hair cells, rat auditory nerve fiber and spiral ganglion losses increased with doses above 50 μM with the highest dose destroying virtually all SGN. The remarkable species differences seen in vitro suggest that chinchilla IHC and type I SGN posse some unique biological mechanism that makes them especially vulnerable to carboplatin toxicity.展开更多
Oxaliplatin, an anticancer drug commonly used to treat colorectal cancer and other tumors, has a number of serious side effects, most notably neuropathy and ototoxicity. To gain insights into its ototoxic profile, oxa...Oxaliplatin, an anticancer drug commonly used to treat colorectal cancer and other tumors, has a number of serious side effects, most notably neuropathy and ototoxicity. To gain insights into its ototoxic profile, oxaliplatin was applied to rat cochlear organ cultures. Consistent with it neurotoxic propensity, oxaliplatin selectively damaged nerve fibers at a very low dose 1 μM. In contrast, the dose required to damage hair cells and spiral ganglion neurons was 50 fold higher (50 μM). Oxailiplatin-induced cochlear lesions initial-ly increased with dose, but unexpectedly decreased at very high doses. This non-linear dose response could be related to depressed oxaliplatin uptake via active transport mechanisms. Previous studies have demon-strated that axonal degeneration involves biologically active processes which can be greatly attenuated by nicotinamide adenine dinucleotide (NAD+). To determine if NAD+would protect spiral ganglion axons and the hair cells from oxaliplatin damage, cochlear cultures were treated with oxaliplatin alone at doses of 10 μM or 50 μM respectively as controls or combined with 20 mM NAD+. Treatment with 10 μM oxaliplatin for 48 hours resulted in minor damage to auditory nerve fibers, but spared cochlear hair cells. However, when cochlear cultures were treated with 10 μM oxaliplatin plus 20 mM NAD+, most auditory nerve fibers were intact. 50 μM oxaliplatin destroyed most of spiral ganglion neurons and cochlear hair cells with apop-totic characteristics of cell fragmentations. However, 50 μM oxaliplatin plus 20 mM NAD+treatment great-ly reduced neuronal degenerations and hair cell missing. The results suggested that NAD+provides signifi-cant protection against oxaliplatin-induced neurotoxicity and ototoxicity, which may be due to its actions of antioxidant, antiapoptosis, and energy supply.展开更多
文摘目的测量常用实验动物内耳前庭感觉区的实际面积和量化分析前庭各个感觉区的毛细胞总数或密度。方法①制作CBA/CaJ小鼠、裸鼠、SD大鼠、豚鼠、南美栗鼠、新西兰白兔和非洲黑长尾猴的球囊斑铺片和椭圆囊斑铺片及壶腹嵴铺片,所有铺片样品来自每种受试动物的6个颞骨,在放大100倍的光学显微镜下拍摄2个囊斑铺片的整体照片;②应用Image J软件的图像测量程序,测量了上述7种常用实验动物球囊斑和椭圆囊斑的实际面积;③用网格将球囊斑铺片和椭圆囊斑铺片照片上的前庭感觉区划分为一个个方块区域。在放大400倍的光学显微镜下准确计数每个方格内的毛细胞数量,然后将每个方格的毛细胞计数结果相加以获得每种受试动物球囊斑和椭圆囊斑上的毛细胞总数;④应用前庭小视野定量观察技术计算出前庭各个感觉区小视野范围内的毛细胞密度。结果①从小鼠、裸鼠、大鼠、豚鼠、南美栗鼠、白兔到猴的球囊斑面积依次为(0.193±0.009)、(0.216±0.008)、(0.323±0.010)、(0.528±0.035)、(0.687±0.065)、(1.237±0.075)、(1.371±0.032)mm 2;椭圆囊斑的面积依次为(0.193±0.020)、(0.208±0.013)、(0.321±0.011)、(0.526±0.034)、(0.795±0.017)、(1.224±0.082)、(1.388±0.048)mm 2;②从小鼠、裸鼠、大鼠、豚鼠、南美栗鼠、白兔到猴的球囊斑毛细胞的总数依次为(2476.3±64.4)、(2389.8±47.8)、(3135.3±191.6)、(4882.2±208.7)、(6128.5±242.9)、(10572.2±464.4)、(10992.7±397.4)个;椭圆囊斑毛细胞的总数依次为(2491.4±54.8)、(2368.0±46.1)、(3218.8±82.9)、(4925.3±271.1)、(7794.0±386.1)、(11347.4±435.7)、(11114.5±410.6)个;③从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的球囊斑微纹区和周边区的毛细胞密度(毛细胞数量/0.03 mm 2)依次为101.0±5.79(微纹区)/120.8±4.15(周边区),95.5±3.91(微纹区)/109.2±5.26(周边区),78.4±6.54(微纹区)/94.8±4.38(周边区),60.0±4.74(微纹区)/84.6±2.61(周边区),57.2±3.83(微纹区)/80.0±3.54(周边区),53.8±4.21(微纹区)/68.0±4.18(周边区)。从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的椭圆囊斑微纹区和周边区的毛细胞密度(毛细胞数量/0.03 mm 2)依次为103.8±5.02(微纹区)/119.2±3.70(周边区),91.2±2.49(微纹区)/106.4±4.16(周边区),74.1±3.54(微纹区)/90.8±3.56(周边区),60.4±4.98(微纹区)/81.6±2.07(周边区),57.8±1.92(微纹区)/77.8±3.70(周边区),54.0±2.74(微纹区)/66.4±2.51(周边区)。从小鼠、大鼠、豚鼠、南美栗鼠、白兔和猴的壶腹嵴毛细胞密度(毛细胞数量/0.03 mm 2)依次为112.4±6.38,105.5±3.51,95.2±3.42,84.0±7.16,78.2±2.86,70.8±2.39。可见由于体型较小动物毛细胞的细胞体比体型较大动物毛细胞的细胞体小,因而体型较小动物的前庭毛细胞密度高于体型较大动物的前庭毛细胞密度。另外,每种实验动物球囊斑和椭圆囊斑微纹区的毛细胞密度相似,周边区的毛细胞密度也大致相同,但是同种实验动物囊斑微纹区的毛细胞密度却低于周边区的毛细胞密度。此外,壶腹嵴毛细胞的密度与球囊斑和椭圆囊斑周边区的毛细胞密度几乎相同。鉴于某些损害因素往往具有选择性破坏囊斑微纹区毛细胞的表现,因此囊斑微纹区的毛细胞密度应该与囊斑周边区的毛细胞密度区分开来进行统计,必要时甚至需要把Ⅰ型毛细胞和Ⅱ型毛细胞也区分开来分别予以病理学改变的定量评估。结论本研究采用的前庭测量方法和获得的前庭各个感觉区的测量数据和毛细胞总数及毛细胞密度,为前庭病理学研究的定量分析提供了有益的参考经验和必要的参考数据。
文摘Carboplatin, a second-generation platinum chemotherapeutic drug, is considerably less ototoxic than cisplatin. While common laboratory species such as mice, guinea pigs and rats are highly resistant to carboplatin ototoxicity, the chinchilla stands out as highly susceptible. Moreover, carboplatin causes an unusual gradient of cell death in chinchillas. Moderate doses selectively damage type I spiral ganglion neurons (SGN) and inner hair cells (IHC) and the lesion tends to be relatively uniform along the length of the cochlea. Higher doses eventually damage outer hair cells (OHC), but the lesion follows the traditional gradient in which damage is more severe in the base than the apex. While carboplatin ototoxicity has been well documented in adult animals in vivo, little is known about its in vitro toxicity. To elucidate the ototoxic effects of carboplatin in vitro, we prepared cochlear and vestibular organotypic cultures from postnatal day 3 rats and adult chinchillas. Chinchilla cochlear and vestibular cultures were treated with carboplatin concentrations ranging from 50 μM to 10 mM for 48 h. Consistent with in vivo data, carboplatin selectively damaged IHC at low concentrations (50-100 μM). Surprisingly, IHC loss decreased at higher doses and IHC were intact at doses exceeding 500 μM. The mechanisms underlying this nonlinear response are unclear but could be related to a decrease in carboplatin uptake via active transport mechanisms (e.g., copper). Unlike the cochlea, the carboplatin dose-response function increased with dose with the highest dose destroying all chinchilla vestibular hair cells. Cochlear hair cells and auditory nerve fibers in rat cochlear organotypic cultures were unaffected by carboplatin concentrations <10 μM; however, the damage in OHC were more severe than IHC once the dose reached 100 μM. A dose at 500 μM destroyed all the cochlear hair cells, but hair cell loss decreased at high concentrations and nearly all the cochlear hair cells were present at the highest dose, 5 mM. Unlike the nonlinear dose-response seen with cochlear hair cells, rat auditory nerve fiber and spiral ganglion losses increased with doses above 50 μM with the highest dose destroying virtually all SGN. The remarkable species differences seen in vitro suggest that chinchilla IHC and type I SGN posse some unique biological mechanism that makes them especially vulnerable to carboplatin toxicity.
文摘Oxaliplatin, an anticancer drug commonly used to treat colorectal cancer and other tumors, has a number of serious side effects, most notably neuropathy and ototoxicity. To gain insights into its ototoxic profile, oxaliplatin was applied to rat cochlear organ cultures. Consistent with it neurotoxic propensity, oxaliplatin selectively damaged nerve fibers at a very low dose 1 μM. In contrast, the dose required to damage hair cells and spiral ganglion neurons was 50 fold higher (50 μM). Oxailiplatin-induced cochlear lesions initial-ly increased with dose, but unexpectedly decreased at very high doses. This non-linear dose response could be related to depressed oxaliplatin uptake via active transport mechanisms. Previous studies have demon-strated that axonal degeneration involves biologically active processes which can be greatly attenuated by nicotinamide adenine dinucleotide (NAD+). To determine if NAD+would protect spiral ganglion axons and the hair cells from oxaliplatin damage, cochlear cultures were treated with oxaliplatin alone at doses of 10 μM or 50 μM respectively as controls or combined with 20 mM NAD+. Treatment with 10 μM oxaliplatin for 48 hours resulted in minor damage to auditory nerve fibers, but spared cochlear hair cells. However, when cochlear cultures were treated with 10 μM oxaliplatin plus 20 mM NAD+, most auditory nerve fibers were intact. 50 μM oxaliplatin destroyed most of spiral ganglion neurons and cochlear hair cells with apop-totic characteristics of cell fragmentations. However, 50 μM oxaliplatin plus 20 mM NAD+treatment great-ly reduced neuronal degenerations and hair cell missing. The results suggested that NAD+provides signifi-cant protection against oxaliplatin-induced neurotoxicity and ototoxicity, which may be due to its actions of antioxidant, antiapoptosis, and energy supply.
